The Computer Metaphor

Is the brain actually a computer? Or is this a metaphor or analogy which is often taken too literally? This issue has come up a few times in the past couple of years, and I wanted to give my take because some common responses do not seem right to me.

I'm going to argue the brain really is literally a computer and that this is not a metaphor or analogy at all. Many of the experts who disagree with this are neuroscientists, biologists and philosophers. We have much to learn from them about how the brain works, but that's not the only issue. To answer the question of whether a brain is a computer we also need to consider what a computer is, and I feel this side of the equation is too often neglected.

Putnam, Searle and Bishop: The Failure of Physicalist Computationalism

I wanted to come out of blog dormancy to write up my thoughts on what I feel is a very important argument against computationalism. The argument advances the view that there is no objective fact of the matter about which computations a physical system is computing, and if this is the case it would certainly seem to problematise computationalism (the view that what it is to be a conscious mind is just to perform the right kind of computation).

In this post I will explain the argument and some of the common responses to it. I'll reserve my own response (which is quite different from that of most computationalists) for a future post.