The following is quoted from a book I’ve been reading: Three Scientists and Their Gods, by Robert Wright. It neatly describes the great mystery of consciousness – something that in our day to day lives we tend to simply experience without thinking about it, but which is profoundly strange when you do stop to wonder, “Who is this ME that is wondering who this me is?”

Why does it feel like something to be a human being?

The depth of this question is best understood in the context of natural selection – not the natural selection that created human beings, necessarily, but natural selection in the abstract. Consider a generic, lifeless planet in another corner of the universe. Suppose that, for some reason, some of its molecules start producing copies of themselves, and that these copies do the same, as do their copies, and so on, ad infinitum. Copying errors are occasionally made, and, by definition, those errors conducive to the survival and replication of the resulting copies are preserved, whereas errors that are not so conducive are not. It so happens that a string of copying errors, guided by this selective pressure, leads to the encasement of some replicating molecules in little cellular houses. In similar fashion – through the selective preservation of mutations – additional layers of protection are added; these houses are integrated into huge housing complexes – mobile housing complexes, no less, complexes that lumber around the surface of the planet. And, necessarily, these complexes handle meaningful information; they absorb molecules – or photons or sound waves – that represent states of the environment and that induce behaviors appropriate to those states. Indeed, this information is sometimes exchanged; one housing complex sends representations to another complex, and these symbols, upon their arrival, induce elaborate chains of internal activity that culminate in appropriate behaviors.

Now, is there any reason to believe that it is like anything to be one of these cellular complexes? Of course not. So far as we can see, these are mere automatons, mere robots; there is no reason to expect them to be anything else. It is pretty difficult to imagine a mutation that would endow them with the capacity to experience sensation, and, moreover, it isn’t clear how such a mutation could help them; everything sensations might seem capable of accomplishing can also be accomplished through the movement of physical information.

This description of evolution could – surprise! – be applied to planet Earth. Indeed, most evolutionary biologists would endorse it as a generally accurate description of how we came to be. Such endorsement amounts to implicit agreement that there is no obvious reason for any of us to be conscious: the phenomenon of subjective experience is evolutionarily superfluous.

All of this would be less noteworthy if consciousness were just another feature, like five-toed feet or whitewall tires. But consciousness – sentience – is precisely what gives life at least a modicum of meaning, and morality a basis. The reason life is worth living is that it has the potential to bring pleasurable sensations – love, joy, etc. The reason it is wrong to kill people is because death deprives them of future happiness they might otherwise have experienced, and because it causes their friends and relatives to experience pain. If there were no such things as pain and happiness – if it weren’t like anything to be alive – what would be wrong with knocking off a few humans on a Saturday night?

So this is what I find so weird about consciousness: the very thing that gives life a kind of meaning is the thing that the theory of natural selection doesn’t quite explain. And this conclusion – which sounds suspiciously like something that would come out of Jerry Falwell’s public relations office – is in fact the product of good, old-fashioned godless determinism. Ironic, no? And shocking, too, if you, like me, have spent much of your life assuming that the theory of evolution pretty much settles every basic mystery about life, with the exception of the origin of self-replicating molecules.

This is not to say that the theory of natural selection is flawed as an explanation of how humans came to be; my devotion to the theory is not diminished by the weirdness of consciousness (though my awareness of the bounds of its power is sharpened.) It is just to say something that I guess most people take for granted anyway: life in this universe is a strange thing.