On the walls of the world (i). Cosmology and its limits.

Human beings, then, are animals set in the organic matrix of the world. Yet because we evolved the ability to think and talk -probably about 40,000 years ago - we are not at all like other animals. We have investigated every aspect of the world around us; not just to exploit it, or to gain food or shelter, but out of sheer curiosity. We have developed mathematics of elegance and power that allow us to think about the first moments of the universe, and to send probes out into space and other planets. We have plumbed the depths of the oceans and climbed mountains; written poetry and music, made abstract art, and sequenced our own genes. Such achievements have led some to think that there is no limit to the sorts of things we can do; and, conversely, anything we cannot investigate is not worthy of consideration.
Yet, despite the extraordinary expansion of the human sphere of influence and understanding, some limits, understood so clearly by Kant, mistily emerge. The two most important are cosmology and psychology: the understanding of the world as a whole, and of ourselves. And, simply because we cannot ever understand these two foundational aspects of our life, I want to argue that in a most profound sense the rest of our understanding, amazing though it is, is left floating in a void that can never be filled; and thus is rendered ultimately empty. Let me try to justify this very strong claim, that I know will be seen to be contentious.
Our views of the world have evolved away from the ancient cosmogenies towards the modern view of the space-time world of Einstein, full of the familiar materials of atoms and their constituents. We also strongly suspect there is a lot of 'dark matter' and indeed energy that we cannot see, and have only a sketchy idea of what it consists of. By measuring the background radiation and looking at the ratio of especially helium and hydrogen in the world, we can deduce that the universe began almost 14 billion years ago. All this should be uncontroversial. We also know that our current models of the quantum world, which are field theories, are not really compatible with Einstein's geometric worldview, and intense efforts are ongoing in order to resolve the differences: leading to such exotica as superstrings etc. All this lies within the purview of science; and just because science has not resolved these issues as yet is simply a sign that it is science and not, say, engineering.
The problems come when we take one further step back and think about the stage before. Even to attempt to formulate the problem, however, immediately runs into problems, because if time began with the universe, there can be no 'before'. As our basic understanding of causality is hopelessly rooted in time (states of affairs are caused by those that precede them), in what way can we formulate what came before the universe? Those who are determined to have some sort of solution talk about 'quantum fluctuations' being the cause of the universe. Apart from the fact that this sort of idea is in fact rather old fashioned and probably untenable, this simply pushes the problem one stage back: for what was the quantum fluctuation of? Such a theory already demands space, time and energy - all the things it is meant to explain. We also hear talk now of 'branes', drifting through multidimensional space (the 'bulk'), and their possible collisions giving rise to the universe. These theories may or may not be ultimately testable; but even if they are, they still do not get us anywhere: they too still demand energy, space and time. If we really want a radical, rather than just local origin of time and space, then we need to assent to the view that out of absolutely nothing - no time, no space, no energy, something came; and furthermore, such an 'event' (if it could be called such) should have a scientific theory to explain it. Of course, we have absolutely no clue about what such a theory might consist of; but more important, we cannot conceive what it might consist of either. For to rely on such an event 'to get things started' seems to be the shipwreck of reason, and of the entire scientific endeavour. It would have to be an event without a cause; and even Hume said that he never asserted anything so absurd as something happening like that. If such a thing can happen, then our attempts to categorise, generalise and predict the world are simply empty.
Suppose, then, that the world really has no beginning: perhaps it has endlessly cycled through time and space, with a popular theory being the expansion and collapse of something like a giant black hole. I believe there are in fact several technical objections to such a view; time and space really did start at the big bang; and even if they did not, all sorts of trouble comes when one considers what entropy is doing during all this (entropy would be conserved; yet we know, as entropy is always increasing, that it started off very low; yet after an infinity of time it should be, to say the least, very very high). And even if we overcome these technical (ie scientific) problems, we are then left in the position, of asserting that something can just be. Indeed, this is the position that some famous philosophers, notably Russell, have adopted: the universe is simply a 'brute fact'. One of the reasons this is so unsettling (apart, again, from its flatly anti-scientific nature) is that if something can just be, it can presumably also just not be. Perhaps the universe could suddenly snap out of existence? In any case, we are left with the biggest mystery of them all - why there is something, rather than nothing, as profoundly unsolvable.
At this point, many of the superspecialists would jump in with a claim that I am pushing a 'God of the gaps' theory: we don't know, scientifically, how the universe came to be, so therefore 'goddidit'. I am not. This is a blog about aesthetics, not about general apologetics. In any case, pointing to trouble at the limits of science is not pointing to a gap (ie an unknown causal mechanism joining two states of affairs), but the end of all states of affairs. It is not a gap, but a wall beyond which we cannot go. What I want to draw attention to, though, is the dizzying sense we get when we contemplate this wall: the wall that is the profound limit to all we can ever know. It disturbs, excites, moves. For, viewed against this backdrop, it becomes clear that all we think we know about the world is similarly limited. After all, cosmology (and indeed the quantum world) long ago departed from the shores of our practical knowledge, and instead sailed out on the sea of mathematical models, with no clear relationship to the world we know. What value, then, in reality, do such models actually have? What does the world really exist of, how did it come into existence, and what sustains it? All these are profoundly unanswerable.

Next clear night, then, stare out into the unimaginable depths of space, and instead of thinking of what we know, think of what we do not know, and can never know. I want to help you to feel the aesthetics of cosmology; the complete sense of insecurity of existence, the enforced humility in the face of total mystery. This is, indeed, the aesthetic sense of the sublime. It is part of our quest.


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