To Frank Tipler, theology must either be nonsense or else become a branch of physical cosmology. Much to his astonishment, he tells us, strong signs of God and the hereafter can be seen in cosmology’s equations. Squeezed together by gravity, in some distant year the universe will be crushed down to a single point. In a crucial sense, all the same, intelligent life will have lasted for ever. And the ‘Omega Point’ to which everything is crushed will be a transcendent, divine culmination of information processing that has become infinite. It will unify an infinite collection of infinitely complex, loving minds, among which will be the infinitely improved minds of you and me.
Tipler is a leading cosmologist. From the possible universes suggested by Einstein’s theory of general relativity, he chooses one which will eventually collapse like a wobbling jelly, its axis of greatest compression changing again and again. Manipulated by our vastly intelligent descendants, the compressions will be maximised. Plenty of energy can then be extracted from them, allowing life to continue ever onwards as the collapse proceeds. (In their efforts to maximise the compressions, our descendants will find nobody to help them. Our failure to detect extraterrestrials is a good indication that they don’t exist, Tipler maintains. If they did, wouldn’t they long ago have spread to the solar system?)
To have any great influence on the wobblings, intelligent life will need to have colonised the entire universe by the day its collapse begins. Although this could be a trillion years in the future, there is no time to lose. Colonisation will have to take place at nine-tenths the speed of light. Technology will soon permit this because only computer-based simulations of humans need be rocketed to remote galaxies. With components tremendously miniaturised, a computer weighing a hundred grams will soon be able to simulate ten thousand living, thinking men and women. At the cost of just a little more weight, one would have everything required for starting up a colony. DNA records could be included, if sentimentalists wanted the colony to become one of flesh-and-blood people rather than simulations.
It may well be, however, that humans will take no part in the colonisation, not even in simulated form. By around the year 2030, Tipler estimates, computers will have intelligences equal to ours. Soon afterwards they will overtake us. They themselves could be the colonists, but they would be our descendants, true persons with a life we had passed on to them.
As the universe continues its collapse, its wobblings will grow ever faster and everything will get violently hot. Life in the form of protoplasm or silicon chips would be vaporised, but new substrates will have been developed. Events will occur at a speed that increases without limit. Here is the key to living for ever in a universe which lasts for a finite number of years only. As measured by the constantly speeding-up tickings (so to speak) of the events themselves, time will stretch onwards infinitely. Living beings could experience infinite sequences of new thoughts, which is what living ‘for ever’ ought to mean.
In order to manipulate the wobblings of the universe, living beings everywhere would have to co-operate, loving one another. Will they? Characteristically, Tipler resorts to the mathematical theory of games and to microeconomics in order to prove that they will. They will be eager to fuse their personalities, with the result that the Omega Point will be just a single person – a person knowing infinitely much. The Omega Point will be infinite in power as well. It will have entire mastery over a universe whose energy has grown without limit, as Einstein’s equations dictate in the case of complete gravitational collapse. The Omega Point will deserve the name ‘God’.
Where do you and I fit into the picture? Well, the beings attempting to keep control of the universe must know all about us, which means forming fully detailed computer simulations of us. And a fully detailed simulation of a dead person, Tipler contends, is the very same person, resurrected. The person’s substrate may have changed to computer-chip silicon or to something able to withstand trillion-degree temperatures, but so what? Structure is what’s important, not stuff: hence Tipler’s idea that highly accurate simulations would serve quite as well as flesh-and-blood colonists. In his eyes, the simulations would be humans in every important respect. With his ‘same structure rather than same stuff’ approach to personal identity, he thinks he can solve Aquinas’s problem of how God can resurrect cannibals as well as their victims.
Having resurrected us, the loving beings of the far future won’t just kill us off: they will invite us to join them. At the moment of resurrection we shall have our earlier defects, for otherwise we’d not be us. But we shall soon become greatly improved, provided we show no reluctance. Loving beings don’t use force, and the reluctant may need long persuasion, or ‘purgatory’. The more eager will quickly enter ‘heaven’. In other words, they will achieve vast growth, both moral and intellectual, ultimately getting the chance to develop infinitely complex minds. But bodily delights will be offered, too, for simulated flesh can feel – and be – every bit as real as real flesh. (Tipler goes so far as to calculate how much you’d be attracted by the beauty or handsomeness of your ideal mate.) And those who like fantasy worlds could be given fantasy galaxies to control. Computers in today’s arcades can roughly simulate oncoming cars: the computers of the far future will have no trouble simulating a galaxy’s every atom.
Infinite progress is very important to Tipler. Anything else would be ugly, he argues, and hence (a step sure to raise many eyebrows) unlikely to be good physics. Freeman Dyson, he notes, has shown how life and thought might continue for ever in an endlessly expanding universe despite the constantly increasing cold, or rather because of it. Dyson explains that as temperatures fell more and more, information processing would require less and less energy. A finite store of energy might thus be used to process infinitely much information! A beautiful idea, at first glance, but to Tipler not beautiful enough. Ugly, in fact, when looked at closely. Dyson’s information processing would necessarily occur in separated regions, each finite in complexity. It would therefore have to repeat itself again and again – think of the monkey who, having at last typed the encyclopedia, is fated to type it again and again at long intervals. To Tipler this would be ‘the horror of the Eternal Return’. Continued existence would be ‘pointless’ in such circumstances.
Actually, he is wrong. Imagine that you returned eternally to the agony of unreciprocated love (which, as Baumeister and Wotman showed in 1992 – a further item from Tipler’s impressive mental storehouse – two out of three adults experience at some stage). Each time the agony would be exactly as awful, or you wouldn’t have genuinely returned. Eternal returns can’t get worse, for instance through being more and more boring: if not bored first time, not bored second time either. And we can’t say that an agony wouldn’t be bad, just so long as an exactly similar agony had been experienced earlier. Now, what applies to the badness of agonies applies also to the goodness of pleasures. Returning pleasures might easily outweigh those repeatedly agonising episodes of unreciprocated passion. Still, even if Eternal Return would be neither ‘horror’ nor ‘pointless’, Eternal Progress could be a lot better. Does cosmology encourage us to hope for it, as Tipler believes?
Look once again at why you and I might expect resurrection. Tipler’s idea, as I said, was that simulations of you and of me, accurate enough to be resurrections, will be needed by the beings of the far future, for control of the wobbling universe. Why? Tipler answers that even the engineers of that future could regulate the wobblings of an entire universe only by exploiting chaos, which would require immense knowledge of the past. They would exploit the fact that tiny events can have huge results, as recognised by mathematical ‘chaos theory’. The classic example is the butterfly which, if given incredibly precise information and access to a gigantic computer, could deliberately induce or prevent a hurricane some weeks later, by fluttering this way or that. Tipler comes up with something yet more startling: a butterfly which could have complete control over Earth’s position in its orbit half a billion years down the road. But in order to plan Earth’s position successfully, his butterfly would have to know immensely much about the world, including the doings of butterflies now dead. Its computer would need to be fed with extremely accurate simulations of those butterflies.
In addition, the world would have to be entirely deterministic, so that the computer could predict events with immense precision. Note that we can talk of ‘exploiting chaos’ while believing in entire determinism. A system that is ‘chaotic’ in the mathematician’s sense is just one whose large-scale events depend very, very delicately on earlier small-scale events.
Suppose we accept the immense computer. In Mind Children: The Future of Robot and Human Intelligence, Hans Moravec suggests that dense nuclear matter will be formed into computers a million million million million million times as powerful as the human mind. Let’s agree that even this could easily be beaten near the Omega Point. There will still be a large difficulty: the difficulty of collecting all the information needed for controlling the world’s chaos. Much of the information will have been thoroughly scrambled: for instance, when light rays were scattered. To make matters worse, the world may be radically indeterministic. Quantum theory seems to give a fuzziness to event sequences, making it impossible to reconstruct them or predict them with complete precision.
Tipler’s responses get very complicated. For a start, he throws radical indeterminism into doubt. With most other experts in what is now known as quantum cosmology, he adopts the ‘Many-Worlds’ approach to quantum theory. That’s to say, he rejects the ‘Copenhagen’ view, according to which events develop fuzzily until observers force them, by the act of observation, to take, absolutely unpredictably, one or other of the theoretically available forms. Many-Worlds Quantum Theory instead has the events taking all those forms, in different branches of a branching cosmos. Observers branch like everything else. The ‘you’ of the present minute, merely one among hugely many versions into which the ‘you’ of the previous minute has branched, may observe a radium atom decaying and a cat dying of cyanide, while the ‘you’ in another branch detects no decay and sees a contented cat.
By accepting Many-Worlds Quantum Theory, does Tipler get all the determinism he needs? It might be argued that he doesn’t, because any particular ‘you’ (or any one version of a butterfly) couldn’t know precisely what existed to be inspected, in the single branch available for inspection, without actually inspecting it, and so couldn’t have predicted it with entire accuracy.
In any case, any obviously practical suggestions for exploiting chaos would involve such things as making mighty asteroids move on delicately different courses, rather than sending butterflies off in new directions or trying to reconstruct the past in enormous detail. In point of fact, Tipler can sometimes be read as suggesting that, while developing a thirst for detailed knowledge of the past would have been necessary for exploiting chaos, it might have been the sheer pleasures of satisfying the thirst that led future beings to resurrect us. Sometimes there is even the suggestion that we’d be resurrected because those loving beings would want to give us happy lives, to compensate for our present miseries. Tipler keeps a very open mind on many issues: a thing to be encouraged, but it can add to a reader’s difficulties.
One queer aspect of the Copenhagen interpretation of Quantum Theory is that it can seem to endow observers with incredibly much power over what is or isn’t real. An advantage many physicists find in the Many-Worlds approach is that it denies us such power. However, Tipler wants us to have it. He thinks that, out of the hugely many worlds of Many-Worlds Quantum Theory, only the observed worlds truly exist. This is his preferred explanation of why the universe which we observe is ‘fine tuned for life’, a claim that was investigated in the book which he and John Barrow co-authored, The Anthropic Cosmological Principle. It enters, too, into his expectation that our universe will be found to satisfy the many ‘Omega Point Theory predictions’ which he generates. These predictions concern conditions which he thinks must be fulfilled if the universe is to be controllable until the end of time. A collapsing universe in which control was lost wouldn’t be observed to its very end, in which case, he claims, it could never have existed at all.
Any such link between existence and being observed is very controversial. Bishop Berkeley tried to prove that ‘perceived or perceiving’ was what the man-in-the-street meant by ‘existing’, but his arguments are now considered poor. And we certainly seem able to construct mathematical descriptions of the structures of realities unperceived and unperceiving, without falling into obvious nonsense. Still, who knows? Tipler might conceivably be right in thinking that nothing could ever correspond to those abstract descriptions.
How could he deal, though, with events that happened long before any observers had evolved? And what about ones happening today at Earth’s presumably observer-less centre? His reply is that all such events will in fact be perceived when their causal consequences, bearing full information about them, reach the immediate region of the Omega Point. This region will carry all the computing power it needs to unscramble the information. Having done so, it will be perceiving the entire past of the universe. Furthermore, it is true now that it is perceiving things there, in the future. Tipler adopts Einstein’s philosophical position that past, present and future are all real together. Einstein once wrote that the world has ‘a four-dimensional existence’.
Strictly speaking, Tipler tells us, Many-Worlds Quantum Theory denies any definite past for any given event. The situation which you and I observe has, as some of its past histories, worlds in which Julius Caesar never existed. It’s just that an overwhelmingly large proportion of its past histories include Julius Caesar. In the neighbourhood of the Omega Point, the perception of the past couldn’t involve knowing some uniquely true historical record. Instead, it would involve reconstructing all histories compatible with the evidence: the light rays, atomic particles etc which had now entered that neighbourhood.
Tipler next confronts difficulties over whether any structures entering the last stages of a collapsing cosmos wouldn’t be utterly ‘smeared’ by quantum fuzziness, so that information processing would have to cease. His solution is on familiar lines. Remember, the cosmos described by Many-Worlds Quantum Theory has countless branches. Branches with severe smearing wouldn’t exist, he says, because (Bishop Berkeley again) they wouldn’t be perceivable. But alas, avoiding such smearing may be possible only in thoroughly unusual branches. And when branches get very unusual – taking on, as it were, a very strong flavour of ‘No Julius Caesar here!’ – then believing that only these branches exist could be thought unscientific.
‘Unscientific’ is, in fact, quite a common reaction to Tipler’s book. There can seem to be altogether too many reasons for doubting his conclusions. He himself says, on one page at least, that he doesn’t yet believe his Omega Point Theory – but he turns out to mean only that he’s not yet very sure of its correctness. He can remain a good deal too sure for many scientists’ tastes. Still, his book represents a major contribution to the field of far-future futurology which Freeman Dyson opened up, necessarily very speculative but based on actual calculations. Its pages, particularly those of the lengthy Appendix for Scientists, contain much fine scientific material.
For the historian of ideas, too, the book has a lot to offer: accounts of the way the idea of resurrection has been treated by various religions, of the literature on Eternal Return and of scores of other things. And it can be deliciously polemical, pointing out, for example, that medieval schools of theology would have found nothing odd about requiring degrees in physics from prospective students. They did require them, in the physics of their day. The economist, the games theorist, the psychologist, the sociologist, the anthropologist, the philosopher, will also all find themselves catered for by Tipler’s relentlessly inquiring mind.
The Physics of Immortality is, in short, an utterly extraordinary piece of work. Setting out to be a popular book, and largely succeeding thanks to its vigorous English, it still manages to be one which only a very few will understand at all completely – expertise in mathematics, global general relativity, quantum mechanics, particle physics, evolutionary biology, computer science, economics, metaphysics and so on, would be quite a help. In an earlier age, both it and its author would have been burned for its way of reaching God and immortality. Today it will get at least a verbal roasting from many religious people, sometimes on the grounds (which strike me as weak) that it is ‘egoistical’ to hope for immortal bliss, and that we ought to contemplate great art and read the mystics instead of rooting around for proofs of God. It may get harsh reviews from philosophers unwilling to forgive some of its wilder suggestions, such as that real freedom to choose between two things must mean actually choosing both in different branches of a branching cosmos. It will interest many others only as Lady Chatterley’s Lover interested the reviewer in the American Field and Stream: ‘This fictional account of the day-to-day life of an English gamekeeper contains many passages on pheasant raising, ways to control vermin, and other chores and duties. Unfortunately one is obliged to wade through many pages of extraneous material.’ As for me, I found it fascinating.