sábado, 30 de agosto de 2008

Death and Time Traveling Speculations on the science and fiction of dying to get to the future

Death and Time Traveling Speculations on the science and fiction of dying to get to the future

by Jim Walker
Rewritten: 25 Aug. 2001
Additions: 22 Dec. 2005

How would you like to visit other worlds, the stars and planets on the other side of the galaxy? Or how would you like to live in the future, say several thousand years from now? The impenetrable light-speed barrier and the brief life span of humans appears to prevent any entity from achieving these goals. In spite of the life span and light-speed barrier, I will describe, not only how one might get to the stars and to the future, but that one can travel there, not by traveling close to light speed, not at the speed of light, but much quicker. Instantly. Instantly.
Before you commit this idea to pseudoscience, what I will describe does not violate any known laws of physics. Nor will I appeal to scientific speculations on superliminal loopholes, anti-gravity, wormholes, tachyons, quantum tunneling, curved space, etc. I will, however, resort to a thought experiment using fiction as a method to explain the concept.
Time travel occurs in such a facile and straightforward manner that nature has already done it for millions of years. Natural time travel occurs so simply that we tend to overlook it because of its seeming banality. Science fiction authors have expounded on this in its mechanical manifestation for many years, but always in the wrong context. In Sci-Fi terminology it goes by the term "suspended animation." If you can stop and preserve your information carriers (the molecules, genes, and cells of your body) and restore them to full function at a later time then, in effect, time travel occurs. Regrettably Sci-Fi authors regulate suspended animation simply as a means to preserve human bodies rather than promoting its time jumping properties. In science fiction, the spaceship always gets the credit for the journey but the suspended animation device never receives full due its time & distance travel capacity. To break this impasse requires a shift of perspective, a paradigm shift, to use Thomas Kuhn's phrasing.
Even with the simplicity of the physics involved, unfortunately, the technology does not yet exist to achieve practical time travel for large biological life forms like humans. In spite of this temporary limitation, the technology already exists for preserving small living things such as cells, embryos, and even small animals. In this respect, one can show that, in principle, suspending a large living being falls well within the range of foreseeable technology. To demonstrate just how time travel works requires the use of a thought experiment. Once you undergo this thought experiment, you will understand that instant time travel, indeed, can work, albeit, only in forward time.

Science and science fiction's description of space travel
In science fiction the authors always regulate the spaceship as the sole device for traveling in distance and time regardless of how its crew undergo suspended animation. Among the best known spaceships that used suspended animation chambers include the U.S.S. Discovery (from the movie, "2001, A Space Odyssey"), and the Nostromo (in "Alien").
Other Sci-Fi stories use Faster-Than-Light spaceships such as Star Trek's Enterprise which uses warp-drives. In the movie, Star Wars, the Millennium Falcon used hyperdrives to achieve Faster Than Light (FTL) velocities through hyperspace. The Guild Heighliner in Frank Herbert's "Dune" can "fold" two spacetime points together and transport itself without moving.
In science & technology, aerospace engineers usually attempt to design spacecraft capable of achieving the fastest possible velocity through space. In the 60s, for example, Robert Bussard of the TRW Corporation proposed using interstellar hydrogen atoms as fuel for a ramjet. An enormous scoop would collect and funnel the hydrogen into a nuclear reaction motor. The faster it goes, the more hydrogen it collects and the more efficient it becomes. The British Interplanetary Society came up with a Project Daedalus to design a craft using thermonuclear reactions to achieve velocities of about 10 to 16 percent of the speed of light. At these velocities it would take approximately 40 years to reach a star 6 light-years away. [Herbert]
Needless to say, all of these sub-light-velocity spacecraft lack the capability to travel galactic distances within the life spans of their passengers. Even if scientists figure out how to travel at light speed velocities, consider the vast impracticability of it. Even at warp factor 8 (the maximum velocity of the first Star Trek Enterprise), it would take 195 years to cross our Milky Way galaxy, which has a diameter of around 100,000 light years. (Warp factor 8 equals 512 times light speed. Warp factor 1 equals the speed of light , the total velocity equals the cube of the warp factor.) Clearly, light speed travel, even at warp speeds, (even if achieved) would deem abysmally insufficient as a usable form of galactic space travel.
Science and science fiction's concept of time travel
Perhaps the most renown story of time travel comes from H.G. Well's 1894 classic, "The Time Machine." Most time travel stories describe both backward and forward time travel. One of my favorite stories come from the movie Somewhere in Time (1980), even though it doesn't involve a machine. Unfortunately, none of these stories describe a convincing mechanism for actually achieving time travel, and many don't attempt an explanation at all. Of those that do, they borrow from the speculations of scientists. We also have to disregard the paradoxical inconsistencies and the violations of causality (for example, what happens if the time traveler kills his father before the time traveler's birth, etc.).
When physicists hypothesis and speculate on time travel, it comes simply to that. Speculation. In their attempts to propose a method of time travel, they can only resort to the most hypothetical aspects of relativity or quantum theory such as time compression light-speed travel, FTL, superluminal loopholes or quantum tunneling. Although, point particles such as electrons can achieve a kind of time jump (quantum tunneling), but when the hypothesis gets applied to macro objects the size of living beings, the concept falls apart. Regardless of the attractiveness of their speculations, the problem lies in the inability to design a machine, in principle, to satisfy their hypothesis. Indeed, it may turn out that superluminal loopholes and wormholes have no validity whatsoever (most scientific ideas do not pan out). Our method of time travel avoids all the trappings of these hypothetical guesses.

Nature's time travelers

Examples of nature's time travelers
Nature and natural selection have utilized time travel via suspended animation for millions of years, all without using quantum loopholes. Seeds provide the most common example of natural suspension. Some seeds like those from Lotus plants last as long as 2000 years and can still germinate. Spores, and microbes have remained suspended for hundreds, and in some cases, millions of years before they come to life. Bacterial spores have lasted for 25-40 million years discovered in a bee preserved in amber. In 2000, scientists revived bacteria that had lain in suspended animation for 250 million years encased in salt crystals deep in the earth. [see article]
Brine shrimp give another excellent example of nature's time travelers that you can test out for yourself. You can actually buy dried brine shrimp eggs from most pet stores (aquarium owners use brine shrimp to feed their fish). Brine shrimp eggs come in a can or packet and you can store them for long periods of time. In the can, they look like dried brown powder. Just sprinkle them into purified water and stir gently for about one minute and they will hatch. Instant life!
Insects such as periodical cicadas suspend their lives while in the nymph stage. They emerge after 13 or 17 years, literally time-jumping past the life span of possible predators. According to Lloyd and Dybas, in any particular area, all life cycles remain synchronized, with the result that each area experiences a cicada plague every 13 or 17 years. This presumably results in predators being swamped in plague years and starved in intervening years. Lloyd and Dybas suggest that the long life cycle results in an 'evolutionary race through time.' Interestingly, the time periods always come in prime number sequences (17 or 13) because a predator with a shorter life cycle might synchronize with the cicadas every second or every third time around! [Dawkins]
In another example of natural time travel, some species of frogs can go through the winter with one-half of their body's liquid turned into ice. In this frozen state, they can go without breathing, eating or even without a heartbeat. In the spring, they thaw out and live out their lives. [Health, Mar.1987]
Unfortunately humans have yet to achieve time travel but some think that Keith Richards of the Rolling Stones might have something to do with it. Actually he doesn't time travel at all; he just looks aged beyond his time.

Suspended biological animation in the laboratory
For years scientists have suspended various life forms by the process of freezing. Live blood cells have remained suspended for as long as ten years by protecting them in low concentrations of glycerol (to prevent crystallization and destruction of the cell walls). The blood gets frozen in liquid nitrogen at around -150 C. Thawing the blood takes about ten minutes [Technical Manual of the American Association of Blood Banks].
According to reports, the first successful animation of a mammal occurred in 1951 by a Yugoslavian biologist who froze hamsters for several hours. In the 80s, the biologist Paul Segall claimed to have suspended two dogs by replacing their blood with a cryoprotectant (an antifreeze), and brought them back to life after 20 minutes of suspension. The dog's hearts had stopped beating and by all standards, had died and then came back to life [Health, Mar. 1987] Today, various cells, tissue, sperm and even human embryos get commonly stored in cryogenic suspension for years.
Although no one has yet suspended life forms as large as a human being and brought them back to life, nothing in physics prevents this, at least in principle. The difficulty in suspending a large body mass comes with freezing tissue cells deep within the body at the same time as all the other cells and without destroying them by crystallization. Fortunately there does exist, promising new techniques that may produce practicable freeze suspension methods. Some of these methods use a form of magnetic cooling.

Magnetic time suspension
At Los Alamos National Laboratory, researchers have developed a new type of cryogenic refrigerator, a magnetic unit that uses the magnetocaloric effect (MCE). The magnetic refrigerator has many advantages over conventional gas-liquid refrigerators. Because they use a magnetic field to cool a refrigerant, magnetic refrigerators don't carry the energy-draining baggage of conventional machines. Magnetic refrigerators can operate at up to four times the efficiencies of conventional coolers and have very few moving parts. Magnetic refrigerators also have a higher cooling capacity per unit volume than gas-liquid freezers because of the density of the magnetic material. As development continues superconducting magnets should yield even more efficient and powerful refrigerators. [Chemical Week, Sep. 4, 1985]. [Also check out these sites: 1, 2, 3, 4, 5]
If for one moment you doubt the ability of energy fields to suspend objects in time, consider the experiments of Lene Vestergaard Hau, professor of Applied Physics at Harvard University where he successfully froze atoms to the point of suspending the energy of light that relays to and from them. By using a magnetic field to trap sodium atoms, and using coupling lasers, Hau and his team have frozen atoms to within a millionth of a degree of absolute zero. The information that produces and transmits the light actually gets stored within the atoms and thus he has effectively stopped and restarted light within a test chamber. ["Frozen Light," Scientific American, Jul. 2001]. If you can suspend the movements of matter and energy, you have essentially stopped their time. (Note, that although I accept the idea of freezing atoms, I feel suspicious of their terminology of freezing light. Light may not exist between events at all. See "Does Light Exist?")
I will use magnetic suspension technology to illustrate a thought experiment (below), but first we need to understand a little bit about the nature of time and space.

The interconnection of time and space
"Henceforth, space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an independent reality."
-Hermann Minkowski
Scientists think of time as a measured movement of some external object or simply the period of an event. For example, one earth year represents the period of duration of our planet moving once around the sun. A day represents the period of one planetary rotation about its axis, etc. Virtually all expressions of time represent some form of measured events.
One of the most interesting consequences of Einstein's relativity theory comes with the realization that you cannot separate space from time. The four-dimensional continuum consists of the familiar three spatial dimensions and the temporal or time dimension which, together, physicists call spacetime. Actually Einstein didn't come up with the idea of 4-dimensional spacetime but rather it came from Minkowski's geometric formulation of the theory of Special Relativity, where later Einstein incorporated the spacetime continuum into his general theory of relativity.
To better understand the meaning of dimensions, think of them as the coordinates necessary to find an object in space. To locate, say, an airborne aircraft, you would need to know 3 coordinate dimensions: the longitude, latitude, and the altitude above sea level. But you would also need to know the time at which to find the aircraft at those dimensions. Therefore you also need time to locate objects in space. Physicists think in terms of spacetime rather than space and time because when you alter space, you invariably alter time, and vise-versa. Thus space and time have no more independence of each other than the three dimensions of space [Russell]. This bears importance for understanding time travel because when you travel in distance, you travel in time; when you travel in time, you travel in distance. One cannot avoid this interconnection. Unfortunately, the direction of travel goes only one way in our experiment. Once you commit yourself to the future, you cannot come back. Sorry.
An intriguing aspect of time travel comes with the realization that if you go very fast, time appears to slow down. Relativity theory predicts that as a material object approaches the speed of light, three things happen: mass appears to increase toward infinity; one of the spatial dimensions shortens toward zero; and time slows to a stop [see light-speed chart]. This presents us with the light-speed barrier, for to accelerate an object to the speed of light would take an infinite amount of energy and would result in a infinite mass, a loss of a dimension, and stopped time. Needless to say, light-speed travel presents vast difficulties, not only in expense but in efficiency.
However, if you do the opposite of going fast, you get the benefit of not only traveling in spacetime, but the cost of building a time-machine becomes considerably lower. By suspending and stopping every cell in your body though some process of controlled dormancy you would, in effect, drastically alter time from your perspective. Of course when you stop all your life processes, you would essentially have killed yourself, at least temporarily. Ironic as it may seem, by dying, you can extend your life into the future and achieve instant spacetime travel. To illustrate just how this works requires a thought experiment.

A spacetime travel thought experiment
"Sleek. Fast. Handles like a dream. Delivers the ultimate performance. From 0 to 800,000 years in 1.2 seconds."
-from the 2001 movie trailer, The Time Machine
Imagine for the moment that a group of physicists and engineers have developed an efficient biological suspension chamber that can hold a single human being. For the purpose of this thought experiment, imagine that the chamber uses magnetic field technology where superconducting magnets can literally halt the vibrations of every atom within its chamber. Instead of freezing a refrigerant (as present MCE units do), imagine the human body itself, as the refrigerant! If a human happens to sit in the chamber with the magnetic field turned on, every cell in the body would undergo virtually instantaneous super-cooled freezing which avoids the problems of cell crystallization produced by slow gas-fluid freezers. Computers control all operations, from turning on the magnetic field and holding the body in suspension. When arriving at its time destination, the computers shut down the magnetic field which instantly returns every atomic structure of the body back to its previous state, thus avoiding the difficulties of slow-thawing.
Because the chamber has automatic computer control capability, this allows a single person to operate the time-machine from a simple instrument panel without assistance from anyone else. Fortunately you had the funds available to purchase the first model and you get to serve as the test pilot.
Your spacetime-chamber looks like this:

(Click on picture for details)

Now imagine yourself as the pilot of this craft. In spite of it being bolted to the floor and the realization that this machine will halt every atom in your body, you will shortly embark on a journey of millions of miles and into the future. Instantly. Remember, nothing here violates any known law of physics.
You climb into the chamber and clamp the side door shut. Before you appears an instrument panel:

The controls appear simple. You see a digital clock with the present time showing. Below that you see a "stop time" clock where you can enter the time period you wish to appear in. You dial in a timer to set the count down cycle. If, during the count down you wish to halt the procedure, you can simply hit the "cancel" button.
Let's say you entered the chamber on Oct. 15th, 2001 and you wish to suspend yourself for one year. You set your destination or stop time one year ahead to Oct. 15th, 2002. To give yourself a little time to settle yourself before your journey, you program the count-down timer for 10 seconds. When you feel ready, you press the "GO" button and wait for your travel to begin. The process starts automatically. The computers take control and prepares to turn on the magnetic field. The timer begins its count down: ten, nine, eight, seven... Your anxiety rises. Six, five, four, three... You feel your heart pounding. Here we go! Two, one, zero...
Something went wrong. Nothing happened. Strangely the present-time clock reads the year 2002 and you feel frustrated. You climb out of the chamber and check out the equipment. Nothing seems wrong. You go to the nearest newsstand and to your amazement, all the newspapers have 2002 dates. You realize that, indeed, the time machine worked! [Click on the instrument panel above for details]
Not only have you jumped into the future by one year but you have traveled a distance of 584 million miles, the distance of the orbit of the earth around the sun! And you did it instantly. (And this doesn't count the distance you traveled around each revolution of the earth.) The interconnection of space and time yields that traveling in time means traveling in distance. If you had set the clock to 50 years ahead, you would have traveled 50 times around the sun and when you woke up, everyone around you would have aged 50 years (or died) and you wouldn't have aged at all.
But why wouldn't you feel anything? Because while undergoing time-suspension you would have no feelings to feel with. You would have died. Your body would have lain in a deceased state for an entire year, halted in the present like a movie in freeze frame. The zero on the count-down timer would appear as the last and next thing you saw after a year of suspension. The interval between the start and stop, to you, would seem instantaneous. It doesn't matter if the interval consists of a second, a year, or a million years; as long as all body functions get stored and revived as before, the time period would appear instantaneous from the perspective of the time traveler. Relativity theory posits that no frame of reference gives precedence over any other frame of reference. Your reference appears just as valid as any other. So from your point of view, you would have jumped ahead one year with the added bonus that you wouldn't have aged at all. For those outside the chamber, you would simply have appeared dead for one standard earth year.
You might find it fun to contemplate what you could do with such a time machine. If I had the fortunate opportunity to own such a device, I think I would install it in an undisclosed location, perhaps in a cave to protect it from the environment and from unscrupulous people. A nearby stream or river could supply the necessary energy to drive a small electrical turbine to supply power for the computers and the magnetic field. I wouldn't tell anyone about it. At first, I would time-jump in weekly stages. Visiting family and friends over the weekends could prove interesting, especially if you don't tell them your secret of staying young after so many years. When your friends have reached old age, you would still appear young. After everyone you know had died, you might want to take longer time jumps, perhaps months or years into the future. Unfortunately these time jumps can only go one way; you can't go back in time. But if you feel unhappy in a certain time period, you can continue time-jumping until you reach a more favorable time. If a dangerous period occurs, say a war or worldwide depression, you could literally jump around it into a more settled future. Have fun, make new friends, perhaps stay for awhile. Money should present no problem. Investing in an interest bearing account for many years without touching it would yield a nice nest egg. You wouldn't have to work! Storing away collectables would turn into valuable antiques. Even cheap nostalgic items like toys, coins, and pop icons should dramatically increase their value after hundreds of years. You might even reach celebrity status if nothing more than for your considerable historical knowledge of your time period. And if you could explore the future on earth, imagine what you could do with a time machine installed in a starship to explore the universe?
For a QuickTime teaser of the Dreamworks movie "The Time Machine," click here.

A better way to travel though spacetime
Our thought experiment served to explain the simplicity of spacetime travel by jumping only one year into the future, as an example. Yet, imagine the possibilities of such a machine in space, between the stars, where the natural coldness of space could substitute for the magnetic freezer during long interstellar voyages. (A time-suspended spaceship might utilize a magnetic field to first put human occupants into suspension, then once achieved, it could use the near-absolute-temperature of space to continue the process with virtually no energy input.) All of the energy to run the computers, sensors, and propulsion engines (or light sails) etc., it could get by using photon collectors to store the energy from starlight.
Instead of designing inefficient propulsion engines such a thermonuclear thrusters or anti-matter drives in an attempt to approach light speeds, designers could utilize low energy systems such as ion engines, or photon sails to capture electromagnetic energy. Gravitational sling shot techniques could serve to travel from planet to planet or from star to star while using low power propulsion units for course corrections.
It doesn't matter how long it takes the ship gets there because the time-traveler uses a different time frame reference. The ship exists in universal standard time; the time-traveler's mind and personality, however, doesn't exist at all during the voyage because he or she would remain in a death state until awakened. The time-traveler exists only during conscious states from the time-traveler's own frame of measurement. If something went wrong with the spaceship during the voyage, say, the computers broke down and kept the time-traveler suspended forever, or if an asteroid collided with the ship and blew it to smithereens then we would essentially have to consider our poor space traveler, dead. Forever. Which brings up the next question.

Death, what does it mean?
By all criteria of life as a functioning entity that grows, breeds, feels or thinks, death must then mean its opposite. Death means the termination of life. A life form that does not move, breath, eat, feel, think, or have any bodily function, whether by natural cause, bullet, fire, or frozen suspension, we must consider no longer living. Likewise we must also consider the time-traveler in our thought experiment as having undergone death. Whether the time traveler gets revived or not makes no difference. A nonfunctional life form that no longer has brain waves or consciousness, means death by any biological standard.
Regardless of how obvious this may appear to the materialist, death does not mean ultimate death for many believers, especially the religious. Death to them means a kind of metamorphosis, a transformation into another form. Hindus believe in reincarnations, Christians and Muslims believe in deathless souls that live in eternal hell or heaven (I prefer to call them the undead. Hey, if they can call fetuses, the unborn, then I get to call them the undead. For fairness sake, you know.). The concept of suspended animation should present interesting questions for the theologian or spiritualist because if, indeed, a life spirit world exists beyond biological life, or if souls can live in heaven or hell, limbo or purgatory, or see God, Zeus, ghosts, or Jesus, then just such a time-chamber should present an excellent instrument to answer these questions. If the tunnel-of-light visions in near-death experiences actually pan out then one could simply explore the tunnel by taking a time-suspension journey into death. One could actually investigate where the tunnel leads. Can one really float above their body and observe from another astral dimension? Can one's soul inhabit another animal, or meet with Jesus, or talk with God or see your deceased relatives, or spend eternity meeting the trillions of the undead? (What a horrible thought to think that some other entity has control over your life or that you have to spend the rest of eternity with your relatives, but I digress.)
Of course I have no knowledge about the supernatural but I will bet their lives that none of these spiritual things occur. If the supernaturalists prove right, however, a time-suspension machine would still benefit both believer and unbeliever. For if a godly spirit world exists, believers could explore the supernatural realm, and the poor atheists, who would most certainly go straight to hell, could escape by coming back to our familiar and wonderful sin-filled material world. Whoopee!
The unique thing about suspended animation involves, not only controlling time, but controlling one's life and death and when and where to do it. An experienced time-traveler would have no fear of death for the simple reason that he or she would have undergone it many times. Here we would have the realization of a form of designed reincarnation. Hindus would, no doubt, yawn with the obvious.
Unfortunately for Catholics and many Protestants, to put oneself in such a suspended state means that one has to willingly die, even if temporarily. This amounts to nothing less than a form of suicide which, according to Christian doctrine, means committing a mortal sin. Ironically this would leave the majority of the heavenly explorers to the unbelievers who would have more knowledge about the undead than the religious (if, indeed, the undead realm exists).
No doubt eternal death may still result if your body gets destroyed, but this still leaves an unknown and yet unanswered aspect of possible outcomes. Consider the following proposition:
If something proves possible and if matter-energy-spacetime occurs infinitely and forever, then that something will eventually occur.
Since we know we exist, we know its possibility (at least a probability of 1). Therefore, we need to find out more about infinity. If in any sense this proposition proves correct, the vast time it takes to get to the next possibility would appear instantaneous from the time frame of the entity. But imagine if we have control over our own existence and the time periods we live in, we would in effect, have made the proposition viable.
Considering that scientists continue to improve the ability to record DNA and through magnetic suspension techniques can store energy states, not only should it deem possible to store copies of bodies, but along with it, brains and the emerging property from them-- minds. In the future I suspect that only the person who believes in the spirit world will fear death.
Note: To those who's death will come near, you have nothing to fear. Although dying can produce temporary pain, the Great Sleep comes sweet and forever. No more pain or aching memories, a halt, a stop in time; no scary heavens, no eternal hell. Death erases fear along with everything else. Time passes as if in a time machine, not knowing if the infinity of time will restore life as before, entirely new, or forever and ever traveling in that silent chamber through empty space.

The problem with humans
In spite of my description of human time travel I did this mainly because people love to read about themselves. I pulled a fast on you and I sincerely apologize but I seriously doubt that human beings, at least the 21st century specie, will ever undergo such form of space travel for the simple reason that most people feel too connected to earth's environment to have any real interest in far reaching explorations. Why? Because in spite of our nature to explore other places, most people want to return home to tell the story. Tooling about the solar system describes one thing; leaving the home planet forever describes another. Note that virtually all the spaceships designed for extended voyages past our solar system begin with the premise that they must return to the home planet. This home bound thinking effectively limits the possibilities for practical space travel. Trade-offs must occur and the most dramatic sacrifice comes with the realization that to effectively explore the far reaches of other star systems, one must forever abandon the concept of getting back to the home planet.
Another problem with humans will occur when biologists figure out how to extend the life span of humans. If you couple this with moral laws against contraception, the belief in the fruitful multiplying of people (Gen. 1:22), while ignoring the evidence for increasing pollution and green-house effects, you have the makings of a very crowded and defiled planet. For a terrestrial species to survive and evolve, death appears necessary only when living in an environment with a finite amount of space. But in the vastness of space, eternal death has no necessity. Unfortunately humans have their genes adapted for earth's environment and not for the vacuum of space.
In the 70s, Gerald O'Neill proposed building permanent earth-like structures in space to hold colonies of people. [O'Neill] These artificial planets would not take them to the stars, nor can they compare with the diversity of earth's abundance. Indeed they might serve as useful space rigs, floating hotels, or perhaps temporary homes for asteroid miners. At best they might serve as a replacement planet if we manage to destroy planet earth. Regardless of how close they resemble the earth, they would only have achieved duplicating a home planet and we go back where we started, with a finite amount of space and a requirement for death, or severe population control. If humans can't control a planet, why in the world would we expect them to control an artificial one?
Homo sapiens evolved out of the earth as air breathing, carbon based life forms that require water and the consumption of other DNA based life forms to stay alive. To live in space requires bringing along vast quantities of earth stuff-- food, air, and the ability to eliminate waste products. In spite of genetic engineering, so far, no one has figured out how to make artificial food exempt from genetic material. The necessity of food requires storing or growing or raising genetic based life forms, and in space, this presents a problem. Consider that a suspended animation chamber might adequately service a human being, but the space-ship engineer would also have to make room for many more life forms: the very food products for which a human would need to consume in order to survive.
We would have to confront the realities: living in space means boredom and humans just do not have the biological equipment suited for permanent space voyages. The spaceship designer must consider a vastly different life-form more suited to live in space. In effect this means designing the ship as the life-form and it must forever abandon the earth along with all its cherished beliefs. (I didn't say this would prove easy, only that it would not violate any known physics.)
So forget everything above about the human designed suspended chamber; that served as a step to get you to the next stage. Now that you've got the concept of spacetime travel you can apply it to a better adapted form of life.

Designing a space traveler (Cyber sapiens)
What we need involves putting human evolution into the control of ourselves rather than leaving it up entirely to the contingencies of natural selection. Considering the barriers of religion and the moral henchmen against modifying life, this could take longer to overcome than developing the technology for space travel. Regardless, we need a life form that can adapt itself to space. Instead of living from earth stuff, it would evolve and adapt to the environment of space. Here again this involves nothing extraordinary in physics or biology even though the technology does not yet exit to do so. To design a space-being we might start by taking the natural human qualities such as our thinking and feeling capabilities but with the added ability to live off of another energy source. Instead of biological wetware, digital codes might replace the hormones, cells and neurons of the brain. Instead of living off of genetic material, a cybernetic life form could, in principle, live from the energy of light. Plants do this by their very nature. Computers can operate from solar cells. Whether this form evolves from recombinant DNA techniques, cybernetics, or a combination of scientific techniques, I haven't the slightest idea. The point here aims to illustrate that for an efficiently designed life-form, it should have the ability to live off of starlight, and that nothing here, in principle, violates any known physical laws.
Interestingly, identifying this new life-form would quantum leap all known biological classifications. Not only would this life-form not fit within any specie, genus, family, order, class, or phylum, but it would not even fit within any kingdom! In fact it would not fit within any biological classification system at all. The classification of life would have to split between biological and non-biological life, DNA based and non-DNA based. This new non-biological life would also benefit from having come almost* entirely designed by intelligent beings (whereas biological life evolved entirely through natural selection). The jump from Homo sapien to Cyber sapien would represent a new kingdom of life. Of course evolution will still act on non-biological life, but it will include artificial selection and memes, along with natural selection.
* I say "almost" entirely designed by intelligent beings (us) because blind evolution still works within intelligent life. For example, human language, even though practiced by conscious intelligent beings, did not get designed by humans through conscious design. Who, for example, designed the French language? No one person or a group of people decided to invent French. It simply evolved out of Latin from multicultural people who spoke in different accents across a period of time (and something to think about for creationists who demand transitional fossil evidence, French evolved from Latin [as do all languages], would also have to include transitional languages, not spoken today). Regardless of how much intelligence one has, no being can predict the future with certainty, and blind evolution acts across time through the unpredictably of natural events.
"Death is only a special case of the Second Law."
- Rudolf Clausius [Broda]
In spite of the relative coldness and vacuum of space there exist all kinds of dust particles, gas and high energy cosmic particles flying about. If given only a few years, perhaps even a few hundred years, our space traveler could survive without much of a problem. However the intent of our spaceship aims to live and explore the galaxy in jumps of thousands or millions of years. The accumulated effects of all the cosmic particles, heat, gravitational tidal waves, and who-knows-what over time would eventually lead to a slow disintegration of our spaceship due to the Second Law of Thermodynamics, sometimes referred to as entropy. Rudolf Clausius invented the term in 1865 but it came from Ludwig Boltzmann who gave it the meaning of a measure of disorder or randomness in a closed system. Entropy also results in the arrow of time, since everything eventually degrades over the forward direction of time. In other words, eggs easily break but to put Humpty Dumpty back together again, through chance, violates the Second Law of Thermodynamics. (Actually it doesn't strictly violate the Second Law, but only makes it numerically and impractically improbable.) Even ordered systems such as biological life undergo random destruction over time due to thermal wear (and I don't mean the Fruit-of-the-Loom kind). Sunlight can damage DNA and cause skin cancer; random oxidants can destroy cells. Every life form eventually succumbs to accumulated damage. We all age and then die. The same goes with our spaceship. Eventually it will accumulate tiny crater hits from cosmic particles, a molecule at a time. Imagine our space traveler waking up after thousands of light years only to discover that his ship has become pockmarked with miniature craters. Just a second ago it looked clean and sleek, now it looks like a disintegrated hunk of space debris. Atomic particles can also decay spontaneously over long periods of time. If enough atoms decay in, say, a critical piece of brain circuitry, it might adversely affect the life of our spaceship (this problem would magnify itself in biological death states to the point of possibly preventing them from ever achieving long term storages, thus giving yet another reason why humans don't make good space travelers.) Clearly, allowing our spaceship to decay won't do and we would need to address this problem. Since the unconscious state of our spaceship will undergo many years of suspension, some method of continual examination and restoring of the integrity of the spaceship must occur. Not only the outside hull, but also the insides must keep its functional ability. Our spaceship would also require "eyes" to detect dangerous large objects like stray pieces of dark matter that might collide with the ship.
The spaceship and the space-traveler would, in effect, become synonymous. The ship itself would consist of the body and space as the environment. A human body contains unconscious biological functions (blood filtering, blood pumping, programmed instincts, etc.) and nature's biological robots, the symbiont organisms that help digest our food (for example, E. coli, metabolizing in human guts) and beneficial bacteria to help our immune system . Likewise, our space traveler would also require full autonomy, perhaps using symbiont robots and computer immune-system programs to maintain its existence though space. If something breaks, the spaceship must repair itself. It might head for an asteroid and mine its minerals to build and replace nonfunctional parts. Replacing brain circuits and performing software backups could prevent the damaging effects due to entropy. Instead of using cryogenic refrigerators to freeze biological cells, the conscious part of its cybernetic brain would simply shut down its circuits for long voyages. Considering the speed of today's advanced superconducting transistors and Josephson junctions, switching all circuits on and off should take only a few microseconds. The ability to switch its circuits in such a manner allows this life form to conserve energy and to choose when and where it will exist during its conscious state. From this switching ability emerges a particularly important concept that allows control of velocity through spacetime (explained below).
Our space traveler would utilize computer controlled navigation while it remained in its unconscious shut down state. If some form of, say, dark matter appeared in its path, radar would detect it and the computers would direct its engines to steer around it. In case of an emergency, the computer would wake our space traveler so it could make important decisions.

The propulsion system
Instead of using nuclear explosions, hydrogen-oxygen burning, or some other high energy propulsion method, our spacetime traveler would require a low energy system that could utilize the energy of light from the stars. In this sense the spaceship would serve as a true starship.
One idea that engineers have proposed for moving a spacecraft amounts to using solar sails. A solar sail can capture the energy from a star as long as the spacecraft remained near a sun to utilize its energy (light quanta impart a small momentum on matter, so you'd need a lot of light to produce a usable force). For solar system travel, simple sails would suffice. However, for travel between the stars, a sail alone would not work well because the starlight energy from all directions would cancel out. Some designers have contemplated using lasers to shine on the sail, but this would require a solar system based laser to aim its energy at the sail as it progressed on its journey. We wish to avoid any home-based system because, remember, our spacetime traveler will not return and we want him to live self-sufficiently and with the ability to explore the galaxy. If our spacetime traveler used a sail for interstellar flight, it would need one that reflects photon energy on one side but invisible to starlight from the other. In principle this might work similar to a radiometer which has its rotor blades painted white on one side and black on the other (although a radiometer does not strictly run off light, but rather the photoelectric effect where light heats up the black side and knocks out electrons from its surface. The momentum of electrons leaving the surface propels the rotor, not light directly).
Another method might use an efficient ion engine. Although ion engines have low power, and therefore can only produce very slow accelerations, our spacetime traveler can use all the time necessary to get to where he wants. Unfortunately ion engines require chemicals and this creates storage and entropy problems for engines intended for continuous use.
Perhaps the best way to travel between the stars involves using no interstellar propulsion system at all. In the early 60s, Michael Minovitch pioneered the use of gravitational assist techniques that spacecraft use today for accelerating within our solar system such as the Cassini, Voyager, and Galileo spacecraft [see Gravity Assist Maneuvers]. Future spacetime travelers might use gravitational slingshots as a means to get to other gravitational masses outside our solar system. Stars and massive planets make wonderful gravitational sources. This gives another advantage for cybernetic life forms because to get a good gravitational sling, the starship would need to pass close to a planet or star. Human based spaceships would have to protect its delicate passengers from gravitational tidal forces or heat. A ship protecting a crystal-based cybernetic life form could withstand much higher forces and temperatures. After the slingshot, the starship would coast to the next target star or planet. By using a series of many slingshots our spacetime traveler could literally steer its way through the galaxy. If our traveler used a black-hole orbiting a star for a slingshot source, he could achieve very high velocities, perhaps enough to even reach other galaxies.
During the cold emptiness of space between stars, the starship might require short bursts of energy for quick maneuvering to avoid dark matter or stray comets. For this, it could use a more conventional fuel based propulsion system, perhaps hydrogen burning thrusters. However, this would use a minimal amount of fuel which it could replenish by gathering hydrogen from Jupiter-like planets or collecting stray hydrogen atoms along the way. Hydrogen appears as the most common element in the universe so this shouldn't present a problem.
Another problem looms in slowing the starship down to manageable velocities in order to get to its destination. Since this also requires energy, our starship would need a way to slow down without carrying enormous amounts of fuel. Sails might offer one solution again, but in reverse, as a kind of solar parachute. While approaching its destination, it might steer a course along the perimeter of several solar systems while deploying a solar parachute. This would create only a small deceleration but by using several solar sources, it could eventually slow down to approach orbital velocity to its destination planet or star. However it could also use gravitational assistance to decelerate by flying in front of a body in its orbit. The spacecraft Galileo did just this when it arrived at Jupiter, passing close in front of Jupiter's moon Io in its orbit, where it decelerated, helping it achieve Jupiter orbit insertion and saving propellant. [See Interplanetary Trajectories]
Regardless of what form of interstellar propulsion, deceleration or slingshot system gets used, again, nothing here violates any known laws of physics.

Duty Cycle time travel
Perhaps the most fascinating way to travel though spacetime involves using duty cycles. Although natural biological life-forms cannot take advantage of duty-cycle time traveling, it will apply itself best to cybernetic forms of life. The term "duty cycle" comes from electrical engineering terminology. (No, it does not mean Howdy Doody's bicycle.) A duty cycle represents a periodic ratio of on and off states. Usually duty cycles get represented as square waves or rectangular pulses. If you've ever operated your microwave oven at 50% power, or adjusted the thermostat on your air-conditioner, you'd realize that they operate by turning on for a period of time and off for a period of time. Microwaves, stepper motors, power drills, as well as many computer controlled devices use duty cycle power controls. An example graph of a 50% duty cycle showing 5 on-states looks like the following:
Now that you understand duty cycles, imagine a cybernetic space-traveler that controls its own duty cycle to match the aims of its voyage. Since it utilizes electrical circuits, sensors, and software for its intelligence, it can switch its "brain" on and off almost instantly. The on-state part of the duty cycle represents the conscious state and the off-state as the time suspended (death) state similar to our human based thought experiment.
Important to the concept, you should understand that the off-state part of the duty cycle would remain off for extremely long periods of time, perhaps hundreds or thousands of years, while each on-state may last only a second or a fraction of a second. However, since only the on-states get perceived, conscious time would appear seamless to the time-traveler. The duty cycle from the perspective of an outside observer for the spacetime voyager might look like this:
With duty cycle time traveling, the experience of traveling through space becomes dramatically transformed. Imagine our space traveler controlling a duty-cycle "throttle" that can accelerate and decelerate similar to driving a Formula-one race car through an Italian road course or a spaceship entering hyper space. If you've ever seen the first Star Wars movie, you know the virtual feeling of flashing past the stars. Our duty-cycle time traveler should experience a similar kind of exhilaration (except that the stars would not appear as streaks, but would pass by like tiny lights in the dark in Star Trek fashion).

The starship, Millennium Falcon, entering hyperspace in the first StarWars movie
Imagine flying through the galaxy the way an airplane soars through clouds. Interestingly G-forces would have no effect on our space-traveler because his awareness (on-states) would appear between stars while the starship travels in constant (non-accelerating) standard universal time. (Actually you wouldn't feel acceleration even while using a gravitational sling shot because you would freefall toward the gravitational source, similar to the acceleration of a sky diver falling toward earth.)
One light year represents the distance traveled at light-speed in a vacuum for a period of one year. This calculates to a distance of approximately 5.88 trillion miles. But to the space voyager, the conscious period would feel continuous and he would have no awareness of the off-states. Our spacetime traveler would experience a period of 5 seconds of consciousness like this:
So in 5 seconds our voyager would have traveled a distance of 4 light years or over 23 trillion miles!
In these illustrations I have given each conscious state a period of one second. Actually it would more likely fall far shorter. A human brain processes visual stimuli within about 50 msec [Dennett]; an advanced computer could switch in microseconds. Since it would power on for only a few microseconds every light year or so, the power consumption would prove exceedingly low.
If you still have a problem understanding this, imagine a camera in a spaceship taking a snapshot of the universe at a distance of every light year or so. After you've taken a thousand snapshots (covering 1,000 light years) and assembled each snapshot into a movie film, you'd have about 30 seconds of film showing a voyage through the universe (motion-picture frames display between 24 and 30 frames per second). If our time traveler set his duty cycle at this rate, it would take only a few days (from his time frame) to reach the other side of the galaxy! Of course our time traveler could get there instantly if he set the duty cycle to one cycle (off when you begin the journey and on when you arrive).
A spacetime traveler could also accelerate or decelerate by adjusting the duty cycle to match "throttle" and "brake: inputs:
The down side of this kind of space travel, but only from an earth based perspective, comes with the realization that planetary civilizations would rise and fall within a few cycles of the journey. The term "home" would have no meaning for such a being except in the context of the starship's body itself. Since our space traveler controls its spacetime, it exists when and where it wants. Homo-sapiens control only three dimensions, but our evolved time traveler would also control of the fourth dimension-- time.
The following illustration gives one idea of how an early evolved starship might look:

(Click on picture for details)
If the time warp and superliminal wormhole ideas of science prove impossible, then perhaps suspended animation might serve as the only practical way to travel long distances through space. If this serves the case then such beings may have already evolved to take advantage of this. If so, how could they keep in touch with each other?

A spacetime traveler would have a difficult time surviving alone in space, especially considering the unknowns it would encounter. It would appear no more reasonable to expect a spaceship to survive anymore than a single member of an animal specie surviving on a terrestrial planet. Since our spaceship would possess intelligence and awareness, it should have the qualities of all known intelligent mammals-- a social structure. All mammals live within some social group to help them survive so we might apply the same to our spacetime specie. Several spacetime travelers would have an advantage for survival because they could cover more area, explore more star systems, and accumulate more data and knowledge. But to convey this information to each other requires a way to communicate.
The most obvious method of transmission would consist of the fastest known kind of communication: electromagnetic radiation. Our travelers might use radio, microwave, light, or perhaps high energy gamma rays. But even at light-speed velocities, they would have a problem with communicating unless they stuck close together. Consider that it takes 10 minutes for signals to reach Jupiter from Earth, imagine the years it would take to reach even the nearby stars. What they would need amounts to a faster way to communicate. Again, duty cycles come to the rescue. Duty cycle communication. Faster than light. Instantaneous.
Consider two spaceships separated by a distance of 25,000 light years. We'll call them spaceship Evanova and spaceship Zardoz. Let's say Evanova decides to communicate something to her boyfriend, Zardoz, and so sends out a signal to him. (Yes of course, sex in space!) But right after Evanova transmits, she shuts herself down and goes into a death state. In the meantime the signal would take 25,000 earth years to reach Zardoz. Also in the meantime, Zardoz slumbers in his own shutdown death state. When the signal finally arrives, his onboard computers detect the signal and wakes him up. Zardoz reads the message and sends out a reply to Evanova, and then goes back to sleep (just like a man, eh?). From the perspective of Evanova and Zardoz, they have communicated to each other instantly. In spite of the delay between transmissions, robots and computers could monitor and handle emergency situations while our travelers undergo their off-states. The time-shifted communications should present little problem as algorithms already exist for internet communications that could apply for our spacetime travelers. Computers and software routinely shut themselves off and re-route and receive time delayed information, collated and presented at the appropriate time. Of course our advanced life forms would have to establish and maintain protocols and standards.
Imagine multiple spaceships and intergalactic server buoys sending messages to each other via duty-cycle transmissions. A galaxy network. Each spaceship would experience instant communication with each other while they watched the galaxy slowly spinning around them. Indeed, if you have the power to duty-cycle your life, you could virtually control the spin rate of the galaxy! Relativity theory posits that no frame of reference gives precedence over any other frame of reference.

Transmitting cargo (another form of communication)
Uniquely, not only would a duty-cycle spaceship have the ability to literally time jump at lightyear distances and communicate instantly to other spaceships, but they could also transport cargo to each, again, by utilizing the same method of duty cycles. Just like Evanova and Zardoz communicating a radio message across the galaxy, Evanova could actually transport herself and her cargo to Zardoz. Realistically, transporting material cargo also means transporting information and may actually prove a more efficient way of communication than electromagnetic signaling. Why? Because radio and light transmission loses bit information as the distance increases (the cone of light increases). This means you would need an extremely powerful transmitter just to send simple messages over long distances. Not very efficient. Sending cargo, on the other hand, means sending matter and matter remains compact over long distances, unlike radio communication. You can put a lot of information into atomic structures (think of microchips, brains, and DNA). The downside, of course, means a lot slower transmission method, but this applies only for limited planetary life forms; our time travelers would not have this handicap.
Let's say Evanova finds something interesting, perhaps a few tons of platinum on an asteroid near the Crab Nebula, and decides to give it to Zardoz as a present. After mining the metal, Evanova would tell the computers to navigate toward Zardoz, a thousand lightyears away. Even though it may take millions of earth years to reach Zardoz, from both their perspectives the transportation time would seem instantaneous.
If intelligent life has already evolved to live in space in some manner describe above, then it would present an interesting problem to figure out how we might find such beings. There might exist literally millions or perhaps trillions of thriving space beings living, communicating, and sharing with each other the way social terrestrial beings do on earth. But because they have shifted into a different time frame from terrestrial beings, their communication would appear very slow to us. How in the world could we detect such beings if they exist?

SETI and the search for extraterrestrial life
SETI, the organization for the Search for Extraterrestrial Intelligence devotes itself to finding intelligent life on terrestrial planets. Recently they have embarked on the hunt for high energy light flashes from extraterrestrial beings with the assumption that other beings might use powerful but brief pulses as a kind of light beacon for contacting other life forms. [see news article] However, I submit that if, indeed, life forms capable of such transmissions exist, they may not come from planetary beings at all but rather from evolved interstellar beings traveling and living in spacetime.
Frank Tipler has argued that if extraterrestrial beings exist, our galaxy would have such an enormous number of Von Neumann machine proxies that we could not have missed them [Physics Today, March 1982, p. 26]. This might very well hold for terrestrial beings, but if planet life evolved to live in space, perhaps the spacetime environment demands that such beings must live in extended time periods (duty cycles), and if so, we may very well have missed them. If high energy flashes from intelligent beings exist, such beacons could serve as useful navigation lighthouses for establishing data points for adjusting time cycles and dimensional locations. Discovering and encoding their transmissions may prove difficult if not impossible. A duty-cycle life form would probably not send out its signals in a continuous period of time but rather in short bursts separated by hundreds or thousands of years, perhaps to match its own duty cycles. They may also choose to send their signals cryptographically to keep others from listening in, perhaps cicada-like in prime number sequences. If each pulse represented a bit (or a packet of bits with only enough information for decoding a single bit) and each packet got sent out at random intervals spanning millions of years, it would virtually isolate them from terrestrial beings. Then, again, interstellar life may not transmit by electromagnetic means at all, but rather by sending out matter capsules which could hold vast amounts of information in a more efficient manner. It would come from them to decide to contact us, not the other way around.
Considering that one of SETI's criteria for evaluating signals requires confirmation of more than one signal, this could prove impossible to confirm. Because of the vast expanse of spacetime, the nature of interstellar beings would rarely show themselves to terrestrial beings that live in the constraint of planetary standard time.
Many SETI debates have talked about the possibility that aliens might hold hostility toward other planetary life. Some say we should not try to contact them but only to listen for them. Violence and hostility may very well hold true for terrestrial beings who compete for territory, food, and valuables on a planet with finite resources or who own superstitious beliefs. But does this reasonably hold for beings who might live in the environment of space? If such interstellar beings exist, they would have little need to compete for territory or food for they would live in the vast limitless universe. Obviously a universe provides enough room and material resources for everyone. I can't imagine what reason they would have for need of war or violence. The nature of the scale of the universe and the lightyear distances between stars might very well mold the ethics of such interstellar beings to a benign and peaceful form of existence. What would they need to compete for? The animals on the Galapagos Islands comes to mind here. After many years of evolution without competition, many of the animals on the Galapagos Islands have evolved as non violent creatures and without fear of predators. In fact, the expanse of the universe may very well bar violent terrestrial beings from reaching other inhabited planets at all; perhaps only evolved space travelers could make such journeys. If they decided to live in space, the very nature of the universe might very well force them to evolve in a propitious manner. Certainly an evolved space-being would have high intelligence and no doubt would have an awareness of terrestrial inhabitants. If such beings found earth and examined our life, they would probably not feel impressed. Why would an advanced intelligent being want to communicate or have an interest with earthlings who kill each other over supernatural beliefs, who have an excessive interest in themselves, and where some of them actually love to watch Pro wrestling?

From machine life to star life
"I would almost conjecture that a fixed slow-motion camera occupies their cranial space, and that they gauge all their movements by this markedly different clock upon the world."
-Stephen Jay Gould [Gould]
From here on, only speculations can fuel our imaginations. The results of self-evolution would explode with possibilities. At no time before on earth's history would a life form have the capacity to evolve with such rapidity. The step-by-step process from biological life to cybernetic replicants; making use of Einstein's theory of relativity to modify life-cycles to achieve spacetime travel; all these advances do not violate any known laws of nature. If intelligent terrestrial life has evolved past planetary disasters, biological threats, and supernatural beliefs, the universe would appear open wide for them. Once in space, their future progeny would appear like no other specie on earth. They would appear as dark matter to 21st century humans. Their long term duty cycles might explain why we haven't found them or ever will find them. However, there might occur volumes in the universe where they might roam more than in any other volume.
An evolving life form in space might take advantages of certain places within the galaxy. It would need materials, fuel, and energy to sustain itself-- its food. Perhaps the prime area for gathering such materials might occur in the place where all the atomic elements reside. Supernova halos might serve as an excellent source for harvesting the elements since novas create the heavy elements and throw them out along with the lighter elements. They might even take advantage of using an isolated black-hole as a massive gravitational slingshot to propel them to other galaxies. They might utilize stray star systems between galaxies as oasis points to gather energy for the long intergalactic voyages. So if the possibility exists for us to find them (if they so decide to send out signals to terrestrial beings), perhaps we might best find them at their feeding grounds. If we cannot find individual life forms, perhaps a multitude of them leave a detectable signature. If, indeed, these space creatures exit in the millions, perhaps we could scan areas looking for blinks in the sky (like camera flashes in a football stadium). Looking closer at Nova halos, black holes, and isolated stars between galaxies might reveal these flash signatures where they might tend to communicate with each other in shorter intervals.. These brief flashes would appear to us as random so we probably could not decipher them, but at least we might have some knowledge of interstellar life.
Their duty-cycle lives would play out as though a slow-motion camera occupied their brains. The conjecture in Gould's quote above applied to the common earth sloth, not to interstellar beings, but nothing known in nature prevents such creatures from taking advantage of time-shifting either on earth or elsewhere in the universe.
Imagine cold dead ships gliding silently through space. Rarely seen by planetary beings, they live in periods of microseconds separated by years of unconscious suspension. But to them, they live in different time dimensions, experiencing a thriving life, exploring different worlds, collecting knowledge of the universe and communicating with each other instantly. Instead of genes, they transfer memes (actual meme machines) and they could self-evolve with a rapidity never before seen by natural selection, and perhaps with the ability to evolve until the heat death of the universe.

An evolved spaceform
(Click on picture for details)

The meek shall inherit the earth
According to Psalm 37:11 the meek shall inherit the earth. Considering the boundless belief of the religious, this may very well prove a self-fulfilling prophesy. With the earth's population growing, pollution rising, the greenhouse effect compounding, and the chance of nuclear or biological war increasing, our planet may not serve as a livable planet in the near future. Sadly, many people believe that the world will end by God's hand, as foretold in the story of Revelation, for the sake of an alleged restored paradise [see note 3]. A society that contains such dangerous beliefs just might very well carry it out to make certain the "prophesy" comes true. However, if humans can develop the technology in time before we annihilate ourselves, perhaps we would have a chance at escaping the mess we've created. But to live in spacetime without terrestrial support means throwing away cherished beliefs, traditions, and human customs. It would require self-evolution by transforming our bodies and minds to adapt in space. The first travelers may consist of robots, exploring the solar system and beyond with the ability to fly and navigate without the aid of the earth. Actually this has already begun with NASA's Deep Space One, where a spacecraft uses ion engines and its own autonomous navigation system (Autonav). The next stage might aim to reach the nearest stars, sending back information about celestial bodies, mining distant asteroids and the gasses of heavy planets. This would give us an incentive to evolve the spacecraft further, perhaps including our own neurological makeup into cybernetic neural networks to make it more "human." These stages of evolution would literally transform the human species into another form and for yet unforeseen functions. I think many people would choose to undertake this risk, but not everyone would. So the meek may very well inherit the earth but those who decide to leave will inherit the universe.
Broda, Englebert., "Ludwig Boltzmann: Man- Physicist- Philosopher," Ox Bow Press, 1983
Dawkins, Richard, "The Extended Phenotype," Oxford University Press, 1982 paperback [see page 64-65 for a description of periodical cicadas]
Dennett, Daniel C., "Consciousness Explained," Little, Brown and Co., 1991 [See Chapter 6 on How the Brain Represents Time, p. 144-153]
Gould, Setphen Jay, " Leonardo's Mountain of Clams and the Diet of Worms," Harmony Books, 1998 [See chapter 20, "Can We Truly Know Sloth and Rapacity?"]
O'Neill, Gerald, "The High Frontier. Human Colonies in Space," Bantom, 1978
Russell, Bertrand, "The ABC of Relativity," The New American Library, 1958
Herbert, Nick, "Faster Than Light: Superliminal Loopholes In Physics," New American Library, 1988
Technical Manual of the American Association of Blood Banks, American Association of Blood Banks, 1977
1) Death and Time Traveling developed from an earlier paper , "On Death and Time Traveling," submitted to GEnie (General Electric Information service) in early 1987 and later published in Search magazine (summer 1987).
2) This article deals with forward only time travel. There does, however, exist the possibility for backward time travel without violating any known laws of physics or violating causality but this will take another article for explanation.
3) If for one moment you doubt the seriousness of many religious people who actually want the world to end, check out these scary sites: 1, 2, 3, 4, 5, 6, 7. These provide just a few samples; literally hundreds of such sites exit on the net.
Copyright ® 2001 Jim Walker. All rights reserved
An E-Prime document

Por que a história humana se desenvolveu de maneira diferente em diferentes continentes nos últimos 13.000 anos?

Jared Diamond, palestra na University of California, Los Angeles, 1997
Tradução: Pedro Lourenço Gomes
Atribuí a mim mesmo a modesta tarefa de tentar explicar o amplo padrão da história humana, em todos os continentes, durante os últimos 13.000 anos. Por que a história tomou cursos evolutivos tão diferentes para os povos de diferentes continentes? Este problema me fascina há muito tempo, mas agora está maduro para uma nova síntese por causa dos recentes avanços em muitos campos aparentemente distantes da história, que incluem a biologia molecular, a genética vegetal e animal e a biogeografia, a arqueologia, e a linguística.

Como todos sabemos, os eurasianos, especialmente os povos da Europa e da Ásia Oriental, espalharam-se por todo o globo, dominando o mundo moderno quanto a riqueza e poder. Outros povos, incluindo a maioria dos africanos, sobreviveram e se desligaram da dominação européia, mas continuam na retaguarda quanto a riqueza e poder. Outros povos ainda, incluindo os habitantes originais da Austrália, das Américas, do sul da África, não são mais senhores de sua própria terra e foram dizimados, subjugados ou exterminados pelos colonizadores europeus. Por que a história se desenvolveu desse modo, ao invés de modo reverso? Por que não foram os americanos nativos, os africanos e os aborígenes australianos aqueles que conquistaram ou exterminaram os europeus e asiáticos?

Esta grande questão pode ser um pouco adiantada. Por volta de 1500 A.D., o ano aproximado em que a expansão marítima européia estava apenas começando, os povos dos diferentes continentes já diferiam grandemente em tecnologia e organização política. Grande parte da Eurásia e do norte da África estava ocupada na época por estados e impérios da Idade do Ferro, alguns dos quais à beira da industrialização. Dois povos nativos americanos, os incas e os astecas, governavam impérios com ferramentas de pedra e estavam começando a experimentar o bronze. Partes da África subsahariana estavam divididas em pequenos estados ou tribos (chiefdoms) indígenas da Idade do Ferro. Mas todos os povos da Austrália, da Nova Guiné e das ilhas do Pacífico, e muitos povos das Américas e da África subsahariana ainda viviam como fazendeiros ou mesmo ainda como caçadores/coletores com ferramentas de pedra.

Obviamente, estas diferenças referentes ao ano de 1500 A.D. foram a causa imediata das desigualdades do mundo moderno. Impérios com ferramentas de ferro conquistaram ou exterminaram tribos com ferramentas de pedra. Mas como o mundo se desenvolveu para chegar ao que era em 1500 A.D.?

Esta questão também pode ser empurrada um pouco para trás com facilidade, com a ajuda de histórias escritas e descobertas arqueológicas. Até o final da última Idade do Gelo, mais ou menos em 11.000 A.C., todos os humanos de todos os continentes ainda viviam como caçadores/coletores da Idade da Pedra. Taxas diferentes de desenvolvimento em diferentes continentes, de 11.000 A.C. até 1500 A.D., foram aquilo que produziu as desigualdades do ano de 1500 A.D. Enquanto os aborígenes australianos e muitos povos nativos americanos permaneciam como caçadores/coletores da Idade da Pedra, a maioria dos povos eurasianos e muitos povos das Américas e da África subsahariana gradualmente desenvolveram a agricultura, a pecuária, a metalurgia e uma organização política complexa. Partes da Eurásia, e uma pequena área das Américas também desenvolveram a escrita indígena. Mas cada um destes novos desenvolvimentos apareceu antes na Eurásia do que em qualquer outro lugar.

Assim, podemos finalmente refazer nossa pergunta sobre a evolução das desigualdades do mundo moderno como se segue. Por que o desenvolvimento humano prosseguiu a taxas tão diferentes em diferentes continentes nos últimos 13.000 anos? Estas taxas diferentes constituem o mais amplo padrão histórico, o maior problema não resolvido da história, e são meu assunto agora.

Os historiadores tendem a evitar esse assunto como se fosse uma praga por causa de suas implicações aparentemente racistas. Muitas pessoas, mesmo a maior parte das pessoas, supõem que a resposta envolva diferenças biológicas em QI médio entre as populações do mundo, a despeito do fato de que não há evidências da existência de tais diferenças de QI. Até mesmo perguntar por que povos diferentes têm histórias diferentes parece malévolo para alguns de nós, porque parece estar justificando o que ocorreu na história. De fato, nós estudamos as injustiças da história pela mesma razão por que estudamos genocídios, e pela mesma razão por que psicólogos estudam as mentes de assassinos e estupradores: não para justificar a história, o genocídio, o assassinato e o estupro, mas ao invés disso para entender como estes males vêm a ocorrer e então usar esta compreensão para evitar que ocorram novamente. No caso do cheiro de racismo ainda deixá-lo pouco à vontade para explorar este assunto, apenas reflita sobre a razão básica de porque tantas pessoas aceitam explicações racistas do amplo padrão da história: nós não temos ums explicação alternativa convincente. Até que tenhamos, as pessoas continuarão a gravitar logo de início à volta de teorias racistas. Isto nos deixa com uma grande lacuna moral, que constitui a mais forte razão para se tratar deste assunto.

Vamos prosseguir continente por continente. Como nossa primeira comparação continental, vamos pensar sobre a colisão do Velho Mundo e do Novo Mundo que começou com a viagem de Colombo em 1492 A.D., porque os fatores adjacentes envolvidos no resultado são bem conhecidos. Agora vou lhe dar um resumo e uma interpretação das histórias da América do Norte, da América do Sul, da Europa e Ásia a partir de minha perspectiva como biogeógrafo e biólogo evolutivo - tudo isto em dez minutos; dois minutos por continente. Lá vamos:

Muitos de nós conhecem bem as histórias de como algumas centenas de espanhóis sob Cortés e Pizarro derrubaram os impérios inca e asteca. As populações de cada um desses impérios chegavam a dezenas de milhões. Também estamos familiarizados com os horríveis detalhes de como outros europeus conquistaram outras partes do Novo Mundo. O resultado é que os europeus vieram a colonizar e dominar a maior parte do Novo Mundo, enquanto a população de nativos americanos declinava drasticamente a partir de seu nível no ano de 1492 A.D. Por que isto ocorreu dessa maneira? Por que não ocorreu que os imperadores Montezuma ou Atahuallpa levassem os astecas ou os incas a conquistar a Europa?

As razões adjacentes são óbvias. Os europeus invasores tinham espadas de aço, canhões e cavalos, enquanto os nativos americanos tinham tinham apenas armas de pedra e de madeira, e nenhum animal que pudesse ser cavalgado. Aquelas vantagens militares permitiram repetidamente que tropas de algumas dúzias de espanhóis montados derrotassem exércitos dos nativos que chegavam aos milhares.

Entretanto, espadas de aço, canhões e cavalos não eram os únicos fatores adjacentes por trás da conquista européia do Novo Mundo. As doenças infecciosas introduzidas com os europeus, como varíola e sarampo, espalharam-se de uma tribo indígena para outra, chegando bem na frente dos próprios europeus, e mataram estimados 95% da população nativa do Novo Mundo. Estas doenças eram endêmicas na Europa, e os europeus tinham tido tempo de desenvolver resistência tanto genética quanto imune a elas, mas inicialmente os nativos não tinham tal resistência. O papel desempenhado pelas doenças infecciosas na conquista européia do Novo Mundo foi repetido em muitas outras partes do mundo, incluindo a Austrália Aborígene, o sul da África e muitas ilhas do Pacífico.

Finalmente, há ainda outro conjunto de fatores adjacentes a serem considerados. Como é que Pizarro e Cortés chegaram ao Novo Mundo, afinal, antes que os conquistadores astecas e incas pudessem alcançar a Europa? Este resultado dependeu em parte da tecnologia, sob a forma de barcos oceânicos. Os europeus tinham tais barcos, enquanto astecas e incas não tinham. Além disso, aqueles navios europeus eram sustentados pela organização política centralizada que permitiu que a Espanha e outros países europeus construíssem e equipassem estes barcos. Igualmente crucial foi o papel da escrita européia, ao permitir a rápida disseminação de informações detalhadas precisas, incluindo mapas, orientações de navegação e relatos de exploradores anteriores, para a Europa, motivando exploradores posteriores.

Até agora identificamos uma série de fatores adjacentes por trás da colonização européia do Novo Mundo: a saber, barcos, organização política e a imprensa, que trouxeram os europeus ao Novo Mundo; os germes europeus que mataram a maioria dos nativos antes que conseguissem chegar ao campo de batalha, e canhões, espadas de aço e cavalos, que deram aos europeus uma grande vantagem neste campo de batalha. Agora, vamos tentar esticar um pouco mais a cadeia de causalidade. Por que estas vantagens adjacentes estavam com o Velho Mundo, e não com o Novo Mundo? Teoricamente os nativos americanos poderiam ter sido aqueles a desenvolver espadas de aço e canhões primeiro, a desenvolver barcos oceânicos e impérios e a imprensa primeiro, a estar montados em animais domésticos mais aterrorizantes do que cavalos, ou transportar germes piores do que o da varíola.

A parte mais fácil de ser respondida desta pergunta trata das razões pelas quais a Eurásia desenvolveu os piores germes. É notável como os nativos americanos não desenvolveram doenças epidêmicas devastadoras para darem aos europeus em troca das muitas doenças epidêmicas devastadoras que receberam do Velho Mundo. Existem duas razões diretas para este grosseiro desequilíbrio. Primeiro, a maior parte das doenças epidêmicas conhecidas só podem se sustentar em grandes e densas populações humanas concentradas em aldeias e cidades, que surgiram muito antes no Velho Mundo do que no Novo Mundo. Segundo, estudos recentes sobre micróbios feitos por biólogos moleculares demonstraram que a maioria das doenças epidêmicas humanas se desenvolveram de doenças epidêmicas similares das densas populações de animais domésticos do Velho Mundo, com as quais estávamos em estreito contato. Por exemplo, o sarampo e a tuberculose se desenvolveram de doenças do nosso gado, a gripe de uma doença dos porcos, e a varíola possivelmente de uma doença dos camelos. As Américas tinham poucas espécies nativas de animais domesticados das quais os humanos pudessem adquirir tais doenças.

Agora vamos puxar de volta a cadeia de raciocínio mais um pouco. Por que havia muito mais espécies de animais domesticados na Eurásia do que nas Américas? As Américas abrigam quase mil espécies de mamíferos nativos selvagens, de modo que inicialmente você pode supor que as Américas oferecessem bastante material inicial para a domesticação.

De fato, apenas uma pequena fração de espécies de mamíferos selvagens foram domesticadas com sucesso, porque a domesticação exige que um animal selvagem preencha diversos pré-requisitos: o animal tem que ter uma dieta que os humanos possam fornecer; uma rápida taxa de crescimento; boa vontade de se reproduzir em cativeiro; uma disposição maleável, uma estrutura social que envolva comportamento submisso para com animais dominantes e humanos; e a ausência de uma tendência a entrar em pânico quando posto dentro de cercados. Há milhares de anos os seres humanos domesticaram todas as possíveis espécies grandes de mamíferos selvagens que preenchiam todos estes critérios e valiam a pena ser domesticadas, com o resultado de que não houve adições de valor de animais domésticos em épocas recentes, a despeito dos esforços da ciência moderna.

A Eurásia acabou tendo a maioria das espécies animais domesticadas em parte porque é a maior massa terrestre do mundo e a que mais oferecia espécies selvagens para um começo. Esta diferença pré-existente foi aumentada há 13.000 anos, ao final da última Idade do Gelo, quando a maior parte das grandes espécies de mamíferos das Américas do Sul e do Norte se tornaram extintas, talvez exterminadas pelos primeiros habitantes que ali chegaram. Como resultado, os nativos americanos herdaram muito menos espécies de grandes mamíferos selvagens do que os eurasianos, ficando apenas com o lhama e a alpaca para domesticação. As diferenças entre os Velho e Novo Mundos em plantas domesticadas, especialmente quanto a cereais de sementes grandes, são qualitativamente similares a estas diferenças de mamíferos domesticados, apesar da diferença não ser tão extrema.

Outra razão para uma diversidade local superior de plantas e animais domesticados na Eurásia do que nas Américas é que o eixo principal da Eurásia é de leste/oeste, ao passo que o eixo principal das Américas é de norte/sul. O eixo leste/oeste da Eurásia significou que as espécies domesticadas em uma parte da Eurásia podiam ser facilmente disseminadas por milhares de milhas na mesma latitude, encontrando a mesma duração do dia e o mesmo clima aos quais já estavam adaptadas. Como resultado, galinhas e frutas cítricas domesticadas no sudeste da Ásia espalharam-se rapidamente para o oeste, para a Europa; os cavalos domesticados na Ucrânia espalharam-se rapidamente para leste, para a China, e os carneiros, bodes, gado, trigo e centeio do Crescente Fértil rapidamente se disseminaram tanto para o leste como para o oeste.

Em contraste, o eixo norte/sul das Américas significou que espécies domesticadas em uma área não podiam se espalhar para muito longe sem encontrar duração de dia e clima aos quais não estavam adaptadas. Como resultado, o peru nunca se afastou de seu local de domesticação no México para os Andes, os lhamas e as alpacas nunca saíram dos Andes para oMéxico, de modo que as civilizações nativas das Américas Central e do Norte permaneceram completamente privadas de animais de carga, e demorou milhares de anos para que o milho que se desenvolveu no clima do México se modificasse em um milho adaptado à curta estação de crescimento e à mutante duração do dia conforme as estações da América do Norte.

As plantas e os animais domesticados da Eurásia eram importantes por diversas outras razões que não deixar o europeus desenvolverem germes mal-comportados. Plantas e animais domesticados produzem mais calorias por cada acre (NT - cada acre americano cobre uns 4.000 m2) do que os habitats selvagens, nos quais a maioria das espécies não são comestíveis para os humanos. Como resultado, as densidades populacionais de fazendeiros e criadores são tipicamente de dez a cem vezes maiores do que as dos caçadores/coletores. Apenas este fato explica porque os fazendeiros e criadores por todo o mundo foram capazes de expulsar os caçadores/coletores das terras apropriadas para a agricultura e a pecuária. Os animais domésticos revolucionaram o transporte terrestre. Também revolucionaram a agricultura, permitindo que um fazendeiro arasse e adubasse muito mais terra do que ele o poderia fazer por seu próprio esforço. Além disso, as sociedades de caçadores/coletores tendem a ser igualitárias e a não ter organização política para além do nível de um bando ou uma tribo, ao passo que os excedentes e o armazenamento de alimentos que a agricultura tornou possíveis permitiu o desenvolvimento de sociedades estratificadas e politicamente centralizadas, com elites governantes. Aqueles excedentes de alimentos também aceleraram o desenvolvimento da tecnologia, sustentando artesãos que não criavam seu próprio alimento e que ao invés podiam se devotar a desenvolver a metalurgia, a escrita, espadas e canhões.

Assim, nós começamos identificando uma série de explicações adjacentes - canhões, germes, etc. - para a conquista das Américas pelos europeus. Estes fatores adjacentes me parecem poder ser devidos em grande parte ao maior número de plantas domesticadas do Velho Mundo, ao maior número de animais domesticados e ao eixo leste/oeste. A cadeia de causalidade é muito direta na explicação das vantagens do Velho Mundo referentes a cavalos e a germes mal-comportados. Mas as plantas e os animais domesticados também levaram mais indiretamente à vantagem da Eurásia em canhões, espadas, barcos oceânicos, organização política e a escrita, todos os quais eram produto das sociedades grandes, densas, sedentárias e estratificadas possibilitadas pela agricultura.

A seguir vamos examinar se este esquema, derivado da colisão dos europeus com os nativos americanos, nos ajuda a entender o padrão mais amplo da história africana, que resumirei em cinco minutos. Vou me concentrar na história da África subsahariana, porque ela estava muito mais isolada da Eurásia pela distância e pelo clima do que a África do Norte, cuja história está estreitamente ligada à história da Eurásia. Vamos lá, novamente:

Assim como perguntamos por que Cortés invadiu o México antes que Montezuma pudesse invadir a Europa, podemos igualmente perguntar porque os europeus colonizaram a África subsahariana antes que os subsaharianos pudessem colonizar a Europa. Os fatores adjacentes foram aqueles mesmos já conhecidos, canhões, aço, barcos oceânicos, organização política e a escrita. Mas novamente podemos indagar por que canhões, barcos e tudo mais acabaram sendo desenvolvidos na Europa e não na África subsahariana. Para quem estuda a evolução humana esta questão é particularmente desconcertante, porque os humanos vinham se desenvolvendo por milhões de anos a mais na África do que na Europa, e mesmo o anatomicamente moderno Homo sapiens só pode ter alcançado a Europa a partir da África nos últimos 50.000 anos. Se o tempo fosse um fator crítico no desenvolvimento das sociedades humanas, a África teria desfrutado de uma enorme vantagem inicial sobre a Europa.

Novamente, este resultado reflete amplamente diferenças biogeográficas na disponibilidade de espécies de animais e plantas selvagens domesticáveis. Tomando os animais domésticos em primeiro lugar, é notável que o único animal domesticado dentro da África subsahariana tenha sido (você adivinhou) uma ave, a galinha d'angola (NT - "Guinea fowl", Numida meleagris). Todos os mamíferos domesticados da África - gado, ovelhas, cabras, cavalos, até mesmo os cachorros - entraram na África subsahariana através do norte, da Eurásia ou da África do Norte. A princípio isto parece espantoso, já que agora pensamos na África como o continente dos grandes mamíferos selvagens. De fato, nenhuma destas espécies dos famosos mamíferos grandes e selvagens da África comprovou ser domesticável. Todas foram desqualificadas por um problema ou outro, como: organização social insatisfatória; comportamento intratável; lenta taxa de crescimento, e etc. Pense só no que o curso da história poderia ter sido se os rinocerontes e hipopótamos africanos tivessem se prestado à domesticação! Se isto tivesse sido possível, uma cavalaria africana montada em rinocerontes ou hipopótamos teria feito picadinho da cavalaria européia montada em cavalos. Mas não pode ocorrer assim.

Ao invés, como mencionei, os rebanhos adotados na África eram espécies eurasianas que vieram do norte. O longo eixo africano, como o das Américas, é norte/sul e não leste/oeste. Aqueles mamíferos domésticos eurasianos se disseminaram para o sul muito lentamente na África, porque tinham que se adaptar a diferentes zonas climáticas e diferentes doenças de animais.

As dificuldades impostas por um eixo norte/sul para a disseminação de espécies domesticadas são ainda mais impressionantes para as plantações africanas do que para seus rebanhos. Lembre-se que os alimentos essenciais do antigo Egito eram colheitas do Crescente Fértil e do Mediterrâneo como trigo e cevada, que exigem chuvas de inverno e variações sazonais da duração dos dias para sua germinação. Estas plantações não podiam se disseminar para o sul além da Etiópia, para além da qual as chuvas vêm no verão e há pouca ou nenhuma variação sazonal da duração dos dias. Ao invés, o desenvolvimento da agricultura no Sub-Sahara teve que esperar a domesticação de espécies vegetais como o sorgo e o painço, adaptadas às chuvas de verão da África Central e a uma duração do dia relativamente constante.

Ironicamente, estas plantações da África Central foram incapazes, pela mesma razão, de se disseminarem para o sul, para a zona mediterrânea (NT - "to spread South to the Mediterranian zone of South Africa". Certamente, Diamond não está se referindo ao Mar Mediterrâneo) da África do Sul, onde mais uma vez as chuvas de inverno e as grandes variações sazonais na duração dos dias prevaleciam. O avanço para o sul dos fazendeiros africanos nativos com as plantações da África Central pararam em Natal, para além da qual as plantações centro-africanas não conseguiam se desenvolver - com enormes consequências para a história recente da África do Sul.

Em suma, um eixo norte/sul e uma escassez de espécies animais e vegetais selvagens adaptáveis à domesticação foram decisivos na história da África, assim como o foram na história nativa americana. Apesar dos nativos africanos domesticarem algumas plantas no Sahel (NT - região da África Ocidental entre o Sudão e o deserto de Sahara, onde chove apenas entre julho e outubro, numa pequena média de 5 a 20 polegadas por ano. Na estação seca sopra o vento harmattan, do Sahara, que cria uma constante névoa de fina poeira. A água permanente é rara e a vida selvagem escassa. O capim cresce apenas em pequenos tufos e a vegetação típica são arbustos com espinhos e pequenas árvores), na Etiópia e na África Ocidental tropical, eles adquiriram animais domésticos de valor apenas mais tarde, vindos do norte. As vantagens resultantes dos europeus em canhões, barcos, organização política e escrita permitiram que os europeus colonizassem a África, e não que os africanos colonizassem a Europa.

Vamos concluir agora nossa turbilhonante passagem em volta do globo devotando cinco minutos ao último continente, a Austrália. Lá vamos nós de novo, pela última vez.

Nos tempos modernos a Austrália era o único continente ainda habitado apenas por caçadores/coletores. Isto faz da Austrália um teste crítico para qualquer teoria sobre diferenças continentais na evolução das sociedades humanas. A Austrália nativa não tinha plantadores ou criadores, nem escrita, nem ferramentas de metal, e nenhuma organização política acima da tribo ou do bando. Estas, é claro, são as razões pelas quais as armas e os germes europeus destruíram a sociedade australiana aborígene. Mas por que todos os nativos australianos permaneceram caçadores/coletores?

Há três razões óbvias. Primeira, até hoje nenhuma espécie animal nativa australiana e apenas uma espécie vegetal (a noz da macadâmia) se mostrou adequada para domesticação. Ainda não existem cangurus domésticos. Segunda, a Austrália é o menor continente, e a maior parte dela só pode sustentar pequenas populações humanas, por causa de pouca chuva e baixa produtividade. Portanto, o número total de caçadores/coletores australianos era de mais ou menos 300.000. Finalmente, a Austrália é o continente mais isolado. Os únicos contatos externos dos aborígenes australianos eram tênues ligações marítimas com habitantes da Nova Guiné e da Indonésia.

Para se ter uma idéia da importância daquele pequeno tamanho populacional e isolamento com relação à velocidade do desenvolvimento na Austrália, considere a ilha australiana da Tasmânia, que teve a mais extraordinária sociedade humana do mundo moderno. A Tasmânia é apenas uma ilha de tamanho modesto, mas era a última extremidade do mais remoto continente, e isto esclarece uma grande questão da evolução de todas as sociedades humanas. A Tasmânia fica 130 milhas a sudeste da Austrália. Quando foi visitada pela primeira vez pelos europeus em 1642, a Tasmânia era ocupada por 4.000 caçadores/coletores relacionados aos australianos do continente, mas com a tecnologia mais simples do que de qualquer população recente da Terra. À diferença dos aborígenes australianos do continente, os tasmanianos não conseguiam fazer fogo; não tinham bumerangues, lanças ou escudos; não tinham armas feitas de ossos, ferramentas de pedra especializadas, e nenhuma ferramenta composta, como uma cabeça de machado montada em um cabo; eles não podiam cortar uma árvore ou escavar uma canoa; não faziam costuras para fabricar roupas, a despeito do frio inverno tasmaniano, onde neva; e, incrivelmente, apesar de viverem na maioria das vezes na costa marítima, os tasmanianos não pegavam ou comiam peixes. Como surgiram estas enormes lacunas na cultura material tasmaniana?

A resposta provém do fato de que a Tasmânia costumava ser ligada à parte sul do continente australiano na época do Pleistoceno em que havia uma nível baixo do mar, até que aquela ponte de terra foi seccionada pelo crescente nível do mar há 10.000 anos. As pessoas andavam até a Tasmânia há dezenas de milhares de anos, quando ainda era parte da Austrália. Uma vez que aquela ponte de terra foi seccionada, entretanto, não houve absolutamente nenhum contato posterior dos tasmanianos com os australianos do continente ou com qualquer outro povo da Terra até a chegada dos europeus em 1642, porque tanto os tasmanianos como os australianos do continente não tinham embarcações capazes de cruzar aquele estreito de 130 milhas entre a Tasmânia e a Austrália. A história tasmaniana é, então, um estudo do isolamento humano sem precedentes, exceto na ficção científica - a saber, isolamento completo de outros seres humanos por 10.000 anos. A Tasmânia tinha a menor e mais isolada população humana do mundo. Se o tamanho da população e seu isolamento tivessem qualquer efeito sobre a acumulação de invenções, esperaríamos ver este efeito na Tasmânia.

Se todas estas tecnologias que mencionei, ausentes da Tasmânia mas presentes no continente australiano à sua frente, foram inventadas pelos australianos nos últimos 10.000 anos, podemos pelo menos concluir com certeza que a pequena população da Tasmânia não as inventou independentemente. De modo surpreendente, os registros arqueológicos demonstram algo mais: em verdade os tasmanianos abandonaram algumas tecnologias que tinham trazido com eles da Austrália, e que persistiram no continente australiano. Por exemplo, ferramentas de ossos e a prática da pesca estavam ambas presentes na Tasmânia na época em que a ponte de terra foi seccionada, e ambas desapareceram da Tasmânia por volta de 1500 A.C. Isto representa a perda de valiosas tecnologias: os peixes poderiam ser defumados para fornecer alimento durante o inverno, e agulhas de ossos poderiam ter sido usadas para costurar roupas quentes.

Que sentido podemos tirar destas perdas culturais?

A única interpretação que faz sentido para mim é a seguinte: primeiro, a tecnologia tem que ser inventada ou adotada. As sociedades humanas variam quanto a muitos fatores independentes que afetam sua abertura para inovações. Daí, quanto maior a população humana e quanto mais sociedades existirem em uma ilha ou em um continente, maior a chance de qualquer dada invenção ser concebida e adotada em algum lugar ali.

Segundo, para todas as sociedades humanas, exceto para aquelas da totalmente isolada Tasmânia, a maior parte das inovações tecnológicas se difundem vindo do exterior, ao invés de serem inventadas localmente, de modo que se espera que a evolução da tecnologia prossiga mais rapidamente em sociedades mais estreitamente ligadas com sociedades externas.

Finalmente, a tecnologia não só tem que ser adotada; ela também tem que ser mantida. Todas as sociedades humanas passam por tendências nas quais elas ou adotam práticas de pouca utilidade ou então abandonam práticas de considerável utilidade. Sempre que tais tabus economicamente sem sentido surgem em uma área com muitas sociedades humanas rivais, apenas algumas sociedades irão adotar o tabu em uma dada época. Outras sociedades reterão a prática útil, e ou sobrepujarão as sociedades que a perderam ou então lá estarão como modelos para que as sociedades com tabus deplorem seu erro e readquiram a prática. Se os tasmanianos tivessem permanecido em contato com os australianos do continente, poderiam ter redescoberto o valor e as técnicas da pesca e da fabricação de ferramentas de ossos que haviam perdido. Mas isto não poderia acontecer no completo isolamento da Tasmânia, onde as perdas culturais se tornaram irreversíveis.

Em resumo, a mensagem das diferenças entre as sociedades da Tasmânia e da Austrália continental parece ser a seguinte: Mantendo-se todos os outros fatores iguais (NT - "All other things being equal", o conhecido ceteris paribus), a taxa de invenção humana é mais rápida, e a taxa de perda cultural é mais lenta, em áreas ocupadas por muitas sociedades rivais que tenham muitos indivíduos e que estejam em contato com sociedades de outros lugares. Se esta interpretação estiver correta, então é provável que tenha uma importância mais ampla. Provavelmente ela fornece parte da explicação de porque os nativos australianos, no menor e mais isolado continente do mundo, permaneceram caçadores/coletores da Idade da pedra, enquanto povos de outros continentes estavam adotando a agricultura e o metal. Também é provável que contribua para as diferenças que já discuti entre os fazendeiros da África subsahariana, os fazendeiros das Américas, muito maiores, e os fazendeiros da ainda maior Eurásia.

Naturalmente, há muitos fatores importantes na história do mundo que não tive tempo de discutir em 40 minutos, e que discuto em meu livro (NT - Guns, germs, and steel: the fates of human societies). Por exemplo, eu disse pouco ou nada sobre a distribuição de plantas domesticadas (três capítulos); sobre a maneira precisa como as complexas instituições políticas e o desenvolvimento da escrita, da tecnologia e da religião organizada dependem da agricultura e da pecuária; sobre as fascinantes razões para as diferenças, na Eurásia, entre a China, a Índia, o Oriente Próximo e a Europa; e sobre os efeitos dos indivíduos e das diferenças culturais, na história, que não estão relacionadas ao meio ambiente. Mas agora é hora de resumir o significado total desta viagem turbilhonante pela história humana, com seus mal-distribuídos germes e armas.

O padrão mais amplo da história - a saber, as diferenças entre as sociedades humanas em diferentes continentes - parece-me ser atribuível a diferenças entre os ambientes continentais, e não a diferenças biológicas entre os próprios povos. Em particular, a disponibilidade de espécies vegetais e animais selvagens adequadas à domesticação, e a facilidade com que estas espécies puderam se disseminar não encontrando climas inadequados, contribuiram decisivamente para as taxas variáveis de crescimento da agricultura e da pecuária, que por sua vez contribuiram decisivamente para o aumento dos números das populações humanas, das densidades populacionais e dos excedentes de alimento, que por sua vez contribuiram decisivamente para o desenvolvimento de doenças infecciosas epidêmicas, a escrita, a tecnologia e a organização política. Além disso, as histórias da Tasmânia e da Austrália nos advertem que as diferentes áreas e os diferentes isolamentos dos continentes, determinando o número de sociedades rivais, podem ter sido outro importante fator no desenvolvimento humano.

Enquanto biólogo que pratica ciência experimental em laboratório, sei que alguns cientistas podem se inclinar a descartar estas interpretações históricas como se fossem uma especulação improvável, porque elas não estão fundamentadas em experimentos replicados em laboratório. A mesma objeção pode ser levantada contra qualquer das ciências históricas, incluindo astronomia, biologia evolutiva, geologia e paleontologia. É claro que a objeção pode ser levantada contra todo o campo da história, e a maior parte do campo das ciências sociais. É por esta razão que não ficamos confortáveis ao considerarmos a história como uma ciência. Ela é classificada como uma ciência social, o que é considerado não muito científico.

Mas lembre-se que a palavra "científico" não se deriva da palavra latina para "experimento replicado em laboratório", mas ao invés, da palavra latina "scientia", para "conhecimento". Em ciência, nós procuramos o conhecimento através de quaisquer metodologias que estejam disponíveis e sejam apropriadas. Existem muitos campos que ninguém hesita em considerar como ciência, mesmo que os experimentos destes campos replicados em laboratório sejam imorais, ilegais ou impossíveis. Nós não podemos manipular algumas estrelas enquanto mantemos as outras estrelas como controles; nós não podemos iniciar e interromper idades de gelo, e não podemos fazer experimentos com projeto e desenvolvimento de dinossauros. Mesmo assim, podemos ainda obter consideráveis conhecimentos nestes campos históricos por outros meios. Então poderíamos certamente ser capazes de entender a história humana, porque a introspecção e as obras escritas preservadas nos dão muito mais conhecimento de como eram os humanos antigos do que como eram os antigos dinossauros. Por esta razão estou otimista quanto ao fato de que eventualmente poderemos chegar a explicações convincentes para estes padrões mais amplos da história humana.