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Comment by jerf | Hacker News Reader

I tried leaving this as a comment on the blog, but "Couldn't open socket".

The author, and any reader who finds this interesting, should definitely also read "Why Philosophers Should Care About Computational Complexity" by Scott Aaronson: http://www.scottaaronson.com/papers/philos.pdf

This being the Internet, the natural assumption is that this is intended as contradiction or argument, but I really do just mean, you'll really want to read that too, as it informs the discussion in interesting ways.

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Specifically, section 6 (Compuation and Waterfalls), which gives the answer that System X computes Y whenever it saves you the work of computing Y -- i.e. if being able to use X as an oracle decreases the asymptotic difficulty of Y.

So waterfalls (probably) don't play chess in the sense that any mapping form the waterfall to a chess program would itself be as complex as the problem (and its execution). But a chess computer does, since its output has a very simple mapping to actual moves (and in practice, most chess computers add a view layer to provide that mapping transparently).

Your comment is so much clearer for having a Y. Asking "Does X compute Y" instead of "Does X compute [anything]" makes all the difference.

And also "When does a physical system compute?" (Clare Horsman, Susan Stepney, Rob C. Wagner, Viv Kendon): http://rspa.royalsocietypublishing.org/content/470/2169/2014...

Yes, but they merely spell out Chalmers's implementation relation without even acknowledging it properly:

"The question of when a physical system is computing is fundamentally a question about the relationship of abstract mathematical/logical entities to physical ones [22]."

I had the same problem. My comment:

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"The crucial assumption is that the abstract program, as a mathematical object, requires design and therefore intent. Accordingly, only artificial things can compute. We cannot say, for example, that a brain computes."

I would argue that living things represent the spontaneous emergence of teleology in nature (i.e., evolution doesn't itself have a goal but it implies the greater success of creatures which do have goals). Brains evolved to help organisms survive and reproduce by allowing them to better process sensory data. So brains were "designed" for an "intent" (survival/reproduction), in the sense that brains that did not serve the intent died out.

I suppose you refer to section 6 in his paper which attacks a particular critique of computationalism. I think the particular point he is making is valid. However, the argument this blog post is making is a different one.

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