This NYTimes article on cosmology headed the "most emailed" list for a few hours this morning. I think that this graphic explains the view best. The article's position on this popularity list raises a couple of questions. First, how is it that scientists could hold such a strange view of the universe? And second, why do readers of the New York Times care so much (at least this morning) about this totally strange view?
My problem with Boltzmann's Brain theory (which basically suggests that the probability that we are brains in vats is much higher than the probability that our ordinary commonsense world exists) is that it is not an empirical theory, but a mathematical one. It starts with an idea, the notion that matter is basically a collection of atoms sitting in empty space, and then sets out to ask whether or not our current universe is consistent with that idea. Well, when it turns out that our universe and the original idea aren't too compatible, the reaction that these cosmologists have is to abandon the universe as we know it and hypothesize that our universe is mere appearance. To make this move is to step out of empirical science and into dogmatic idealism--to hold the view that ideas are truer than experience.
For the empirically minded, actuality trumps probability every time. That it is extremely unlikely (on a certain theory) that the universe would exist in its current form is no argument against its actually existing in its present form. In fact, the probability that the universe is as it is seems to me to be incredibly low, as many things are up to chance and could have been otherwise. Lottery winners understand this fact better than anyone else. That there was, in reality, only the most minute probability that they could have won is of no consequence to the winner who hold the million dollar check.
Why are these cosmological theories found so compelling if they replace a rich actuality with the pale image of mathematical probability? My sense is that a clean and clear image of particles floating in space is much more attractive to folks than the complicated, confused, vague, and shifting world in which we actually live. There is something in us that prefers to think of ourselves as brains in vats--because a brain in a vat doesn't have to makes sense of the complicated situations and events that surround us. But even this is an idle hope. If this world were mere illusion, and we were all figments of each others' imagination, then this illusion would be all that we have. Our image of ourselves would be just as valuable to maintain as our real selves now are. And the imagined sicknesses, deaths, joys, and triumphs would be just as heart-rending or fulfilling as the obstacles and pleasures we presently experience.
That we can even conceive of the possibility that we might all be brains in a vat speaks to the intensity with which modern life produces a sense of alienation. We want to take refuge from the hail of experience beneath the shelter of a clear and distinct mathematical idea. If we were just brains in a vat and had no responsibility, no decisions to make, no causes to serve, failure would finally be extinguished from the universe, and onwards we could roll, smoothly and without consequence.
Of course, with the elimination of failure and decay comes the elimination of practically everything else we care for: friends, family, and work. These most precious of relationships are valuable because they are contingent, because they grow and develop (and falter and fail), and because they will come to an end. It is out of this radical contingency, the unbearable lightness of being, that we craft our fragile lives. Because life is fraught with failure, we must respond with care, concern, and passion. Any view that denies this basic character of the universe--the actuality of responsibility--is one that I oppose.