If it survives for a little longer, the human race will probably start to spread across its galaxy. Germ warfare, though, or environmental collapse or many another factor might shortly drive humans to extinction. Are they likely to avoid it? Well, suppose they spread across the galaxy. Of all humans who would ever have been born, maybe only one in a hundred thousand would have lived as early as you. If, in contrast, humans soon became extinct then because of the (...) population explosion you would have been 'fairly ordinary'. Roughly ten per cent of all humans would have been your contemporaries. Now (as the cosmologist Brandon Carter saw to his dismay) a scientific principle tells us not to treat observations as highly extraordinary when they could easily be fairly ordinary. How to apply the principle is controversial, yet it seems we can safely conclude that humanity's chances of galactic colonization cannot be high. Still, we should work to make them as high as possible, resisting those philosophers who argue that human extinction would be no tragedy. (shrink)
The paper develops a Platonic and Spinozistic metaphysics. With an unprovable yet absolute necessity, the cosmos exists just because of the ethical need for it. We, and all the intricate structures of our universe, exist as intricately structured thoughts in a divine mind. This mind could contain infinitely many other universes as well, and minds of the same kind could exist in infinite number. Evidence for this is supplied by the finely tuned orderliness of our universe, and by the sheer (...) fact that any universe exists. (shrink)
A recent book of mine defends three distinct varieties of immortality. One of them is an infinitely lengthy afterlife; however, any hopes of it might seem destroyed by something like Brandon Carter's 'doomsday argument' against viewing ourselves as extremely early humans. The apparent difficulty might be overcome in two ways. First, if the world is non-deterministic then anything on the lines of the doomsday argument may prove unable to deliver a strongly pessimistic conclusion. Secondly, anything on those lines may break (...) down when an infinite sequence of experiences is in question. (shrink)
Might we be parts of a divine mind? Could anything like an afterlife make sense? Starting with a Platonic answer to why the world exists, Immortality Defended suggests we could well be immortal in all of three separate ways. Tackles the fundamental questions posed by our very existence, among them ‘why does the cosmos exist?’, ‘is there a divine mind or God?’ and ‘in what sense might we have afterlives?’ Defends a belief in immortality, without the need for a religious (...) affiliation or rejection of modern science Explores the ideas of ‘Einsteinian immortality’, the divine afterlife, and the theory of an infinite and divine mind Draws from the work of a wide-range of philosophers, from ancient Greece to the present day, and incorporates up-to-date scientific findings Written in a thought-provoking and engaging manner, accessible to anyone intrigued by the wonder of our being. (shrink)
Force strengths, particle masses, etcetera, appear "fine tuned" for intelligent life. There may be many very diverse universes, observational selection explaining why we see a life-permitting one. The alternative is divine selection. The God hypothesis can explain how one and the same force strength or particle mass satisfies life’s many different requirements, and why there are life-encouraging laws of relativity and of quantum theory. It could also answer why any universe exists. God’s existence could be accounted for Platonically, by its (...) ethical requiredness. The most plausible world-view would then be Spinozistic, on lines explored in my recent book "Infinite Minds". (shrink)
The cosmos exists just because of the ethical need for it We, and all the intricate structures of our universe, exist as thoughts in a divine mind that knows everything worth knowing. There could also be infinitely many other universes in this mind....It may be hard to believe that the universe is as Leslie says it is--but it is also hard to resist his compelling ideas and arguments.
Physical force strengths, particle masses, the early cosmic expansion speed and many other factors seem "fine tuned for life". Had they been slightly different, life’s evolution would have been impossible. The situation resembles catching a fish with an apparatus unable to catch ones slightly differently sized. One explanation is that the lake contains fish of many different sizes: multiple universes with randomized characteristics, most of them unobservable because observers cannot evolve in them. Another is that God created a fish of (...) the right size, a universe able to generate observers. The article defends these explanations against numerous ingenious objections. (shrink)
Suppose various observers are divided randomly into two groups, a large and a small. Not knowing into which group anyone has been sent, each can have strong grounds for believing in being in the large group, although recognizing that every observer in the other group has equally powerful reasons for thinking of this other group as the large one. Justified belief can therefore be observer-relative in a rather paradoxical way. Appreciating this allows one to reject an intriguing new objection against (...) Brandon Carter's 'doomsday argument'. Carter encourages us to doubt that we are among only the first hundredth, say, or first millionth, of all humans who will ever have existed. He thereby reinforces whatever reasons we may have for suspecting that, unless we take great care, the human race will not survive long. Admittedly his argument is weakened if our world is indeterministic, so that there is no suitably guaranteed 'fact of the matter' of how many humans will ever have existed. But even then, it can caution us against believing that a lengthy future for humankind 'is as good as determined'. Of all the objections the argument has yet faced, the new one is the most interesting. (shrink)
Abstract An argument originated by Brandon Carter presents humankind's imminent extinction as likelier than we should otherwise have judged. We ought to be reluctant to think ourselves among the earliest 0.01 %, for instance, of all humans who will ever have lived; yet we should be in that tiny group if the human race survived long, even at just its present size. While such reasoning attracts many criticisms, perhaps the only grave one is that indeterminism means there is not yet (...) any firm, theoretically predictable fact of how long the human race will survive. This, though, might not save Everett's many?worlds theory from a variant on Carter's point. Everett seemingly pictures observers as splitting into ever more versions, which explains away all apparent indeterminism; but then, absurdly, all except a vanishingly tiny proportion of one's versions would come into existence near one's death, outweighing all apparent evidence that death was not imminent. The need to avoid such a result severely constrains Everett?type theories. We need theories in which observer?versions diverge without increasing their numbers in any straightforward way. (shrink)
Carter’s anthropic principle reminds us that intelligent life can find itself only in life-permitting times, places or universes. The principle concerns a possible observational selection effect, not a designing deity. It has no special concern with humans, nor does it say that intelligent life is inevitable and common. Barrow and Tipler, who discuss all this, are not biologically ignorant. As argued in "Universes" (Leslie, 1989) they may well be right in thinking that "fine tuning" of force strengths and particle masses, (...) without which life would be impossible, proves the reality of God or else of multiple universes plus observational selection. (shrink)
One of the first books to address what has come to be known as the philosophy of cosmology, Universes asks, "Why does the universe exist?", arguing that the universe is "fine tuned for producing life." For example, if the universe's early expansion speed had been smaller by one part in a million, then it would have recollapsed rapidly; with an equivalently tiny speed increase, no galaxies would have formed. Either way, this universe would have been lifeless.
Cosmologists using the Anthropic Principle claim that if our universe had been much different then nobody would exist to observe it. This may become explanatory when one accepts the actual existence of multiple "universes": gigantic, largely or entirely separate systems having very varied properties. Ian Hacking has urged, though, that an Inverse Gambler's Fallacy is committed during many attempts to formulate anthropic explanations. Besides disagreeing with him, the paper makes several further points in support of such explanations, in particular against (...) the background of the Inflationary Universe. (shrink)
OBVIOUSLY, OBSERVERS EXIST ONLY WHERE LIFE IS POSSIBLE ("THE ANTHROPIC PRINCIPLE"). NOW, THERE MAY BE MANY COSMIC REGIONS, PERHAPS GIGANTIC AND LARGELY OR ENTIRELY SEPARATE "MULTIPLE UNIVERSES," OF WHICH ONLY VERY FEW PERMIT LIFE’S EVOLUTION. GUTH’S COSMIC INFLATION MAY BE INVOLVED HERE, AND DOMAINS WITH DIFFERENTLY BROKEN SYMMETRIES. APPARENT LIFE-ENCOURAGING FINE-TUNING OF NATURAL CONSTANTS MIGHT BE UNDERSTOOD AGAINST THIS BACKGROUND. MANY SCIENTISTS PREDICTIONS RESULT. AN ALTERNATIVE ACCOUNT SPEAKS OF THE WORLD’S CREATIVE ETHICAL REQUIREDNESS ("GOD").