Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature

by Steven Weinberg

It is clear that there is what a literary critic might call an objective correlative to consciousness; there are physical and chemical changes in my brain and body that I observe to be correlated (either as cause or effect) with changes in my conscious thoughts. I tend to smile when pleased; my brain shows different electrical activity when I am awake or asleep; powerful emotions are triggered by hormones in my blood; and I sometimes speak my thoughts. These are not consciousness itself; I can never express in terms of smiles or brain waves or hormones or words what it feels like to be happy or sad. But setting consciousness to one side for a moment, it seems reasonable to suppose that these objective correlatives to consciousness can be studied by the methods of science and will eventually be explained in terms of the physics and chemistry of the brain and body. (By “explained” I do not necessarily mean that we will be able to predict everything or even very much, but that we will understand why smiles and brain waves and hormones work the way they do, in the same sense that, although we cannot predict next month’s weather, still we understand why the weather works the way it does.)