poke comments on Thou Art Physics - Less Wrong

40 Post author: Eliezer_Yudkowsky 06 June 2008 06:37AM

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Comment author: poke 07 June 2008 07:03:00PM 1 point [-]

mtraven, I think your example demonstrates well why computationalism rests on a basic error. The type-token relationship between A-ness and instances of the letter "A" is easily explained: what constitutes A-ness is a social convention and the various diverse instances of "A" are produced as human artifacts with reference to that convention. They all exhibit A-ness because we made them that way. Computers are like this too. Computers can be made from different substrates because they only have to conform to our conventions of how a computer should operate.

The brain is not a computer. Nothing that is not an artifact can possibly be a computer in any meaningful sense (just like a bunch of stones that fall into a pattern resembling the letter "A" aren't the letter "A" in any meaningful sense). It's completely meaningless to call something a "computer" in the way computationalists do. It would make as much sense for me to call the coffee cup resting on my desk an "equation" as it does to call a brain a computer. The coffee cup can be described by an equation. If I throw the coffee cup, for example, I can describe its motion using the standard equations of rigid body dynamics. But the equations I wrote out would not be a coffee cup. The equations are just marks that by convention stand for the motion of a coffee cup.

For some reason, which can probably only be explained through some mix of historical contingency and malicious intentions, people have come up with the idea that when I take that equation and use numerical methods to step through it in a computer program it suddenly becomes the thing it describes. This is rather like thinking a drawing becomes the object it depicts if I turn it into a flip book. Actually, this analogy is very accurate, because as computer program is essentially an equation in flip book form. Anything that can be said about a computer program can also be said of an equation scrawled on a napkin. So, no, you're not a computer or a computation or an equation, you're a physical object.