Map of life expectancy at birth from Global Education Project.

Monday, May 26, 2008

The Big Three

No, I'm not talking about Paul Pierce, Kevin Garnett and Ray Allen. These are three great mysteries that trouble the Enlightenment project -- the quest to understand the universe from the human perspective. These enduring mysteries are among the reasons so many people still cling to irrational beliefs and mysticism. In ascending order of philosophical profundity (in my personal ranking) they are:

The origin of life: This does not in fact present a philosophical challenge to scientific inquiry. It's just a puzzle. We can certainly solve it, in principle, using hard core positivist logic and standard tools of scientific inquiry. The bad news, potentially, is that it happened an awfully long time ago and we just might not ever get a definitive answer. There is a philosophical nugget in there, specifically that there are probably limits to knowledge, there just might be questions that seem very important to us that will always be questions. That may be annoying, or disappointing, but it's not a fundamental challenge to humanism.

Some people, however, feel otherwise, just intuitively. That life could originate without some sentient agent making it happen just seems improbable, or maybe just unsatisfying. Creationists often point to the origin of life as the weakest link in the story of evolution, and perhaps it is. But the fact is we do have a few plausible ideas about how it could have happened, even though we haven't been able to assemble all the pieces of a plausible model. Remember, it only has to happen once -- over millions of years, in the vast volume of the oceans, a single entity that reproduces, but imperfectly, has to occur. And we're off.

Why this universe? There are actually a few pieces of this problem, but they add up to one big one, which is essentially metaphysics. (Some people will say that number 3 -- wait for it -- is also part of metaphysics, and classically it has been, but in the modern formulation of inquiry I would say they are clearly separable.) Why is there anything at all? Why is there this universe instead of some other? And where did it come from, how did it originate? Physicists are busy describing the universe and elucidating its history, but these why and how questions are so far entirely elusive. One thing we have learned is that the facts do not correspond to the beliefs of any religion, so just making stuff up or depending on old fables written in forgotten languages doesn't work.

We know that the universe is bigger and older than the fables say, and that it will endure much further into the future, but it does seem to be temporally finite. We cannot say whether space is finite or not. That is not to say that something may not have existed before the beginning of this universe, from which it arose, and it also may well be that the universe we can observe is embedded in something larger in space as well as time. We just don't know.

As for the three questions within this question:

Why is there anything? Some people don't think that's a big problem. Why should existence be surprising? Of course something exists. Others think non-existence ought to be the default condition and existence requires an explanation. Anyway, religion is no help. If the universe exists because God so ordained, why does God exist?

Why this universe and not some other? One answer which seems plausible though speculative, is that there are many universes, perhaps infinitely many. We just happen to be in this one. In principle, it seems to me, it might be possible to demonstrate that somehow. Of course, by definition, if we could get access to another universe, it would no longer be another universe, but part or our own.

There are two other kinds of explanations. One is that there is something arbitrary about the universe. It just happens to be this way. If you're puzzled about why it just happens to be hospitable to us, that's easy: we're here in the first place because it is. If we were not possible, there might or might not be some other kind of entity contemplating the universe that actually did exist. Cosmologists are generally not happy with this answer because a universe that works essentially like ours, but has tiny differences in basic constants, would vanish in a flash or have no structure. This universe seems highly improbable.

Another kind of explanation is that there are fundamental constraints of logic, some sort of discoverable deep structure, that requires the universe to be as it is. This strikes me as circular.

Where did it come from?This is really no different from part 2, I think. If we could understand why it is as it is, we would probably understand how it began as well.

As before, religion is no help with any of this. If God decreed it all, where did God come from? And why does God want this and not something else? In other words, that's just listing the same questions, again, using a different vocabulary.

What and why is consciousness? This, to me, is the most philosophically challenging problem for science because it seems not to be susceptible to positivist inquiry. The philosophy of science requires that phenomena be mutually observable, that they happen "out there" where we all can see and verify them. But the only consciousness any of us can observe is our own. We can't even know, according to positivist principles, that any other entity is in fact conscious. Maybe I am the only conscious being in the universe. Maybe you think you are.

Neuroscientists have made steady progress in linking reported conscious experiences to observable phenomena in the brain. Quite likely this is possible absolutely, down to the finest-grained possible description of conscious experience. But even if the ghost and the machine can be shown to correspond completely, point by point, would that explain consciousness? To say that consciousness is an illusion is to beg the question. Consciousness is experience. To dismiss experience as illusion is nonsensical and explains nothing.

Consciousness, by its very nature, seems somehow to exist outside of the material universe, to be some other kind of stuff. It is this feeling that gives rise to the conviction some people have of a soul, an immaterial substance that persists after death. I must point out, however, that is far from an inevitable conclusion. Buddha Gautama concluded that the self is an illusion, arising from the temporary confluence of matter that makes the material body and dissolving with it.

Scientists would like to believe that all questions are ultimately susceptible to inquiry. That remains to be seen. However, I do insist that making up arbitrary answers, and believing in them on faith, is not a solution to these problems. Living with mystery may be hard for some people, but ultimately, it is even more rewarding.

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