I tried leaving this as a comment on the blog, but "Couldn't open socket".<p>The author, and any reader who finds this interesting, should definitely also read "Why Philosophers Should Care About Computational Complexity" by Scott Aaronson: <a href="http://www.scottaaronson.com/papers/philos.pdf" rel="nofollow">http://www.scottaaronson.com/papers/philos.pdf</a><p>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.
A computation substrate has state and can change its state within (feedback) loops. An elementary particle suffices this definition: It has state because its properties persist at least for some time, and it has feedback loops (interactions with other particles) that change its state. The more elementary particles locally affect each other, the more complex the state and feedback loops can be. What kinds of computation you can perform on such a substrate depends on the rules that govern the particles, in particular, how many feedback loops they allow to simultaneously affect a local arrangement of particles. It looks like there is an upper bound to this: No substrate can compute more kinds of functions than a Turing machine, which is a hypothesis that is closely tied to the conservation of energy and unitary (that the sum of the probabilities of all possible outcomes of a system equals 1). However, since matter decays, it is doubtful that anything around us can actually be as infinitely precise as the theoretical idea of the Turing machine.
I'm not sure I see the problem with "everything computes". If every physical process can be shown to be isomorphic with one or more computational algorithms, which seems like a very reasonable supposition at this point given what we know about emulation, then that is just the nature of things. It seems more like a useful insight than an unsatisfying answer.
> In conclusion I want to shatter our presumed consensus: computers do not compute. Not even computers. We compute. Computers just help us along.<p>Define "us". Define "compute". Seeing as the former is very fuzzy, and the latter is suggested by the article to be undefined, trying to use this to "prove" that brains are not computers is, well, nonsense.<p>Consciousness is a side-effect of electrochemical interactions. Nothing more, nothing less. Trying to believe otherwise - that consciousness is some "special snowflake" that can somehow exist independently of the machine which creates it - is about as folly as trying to believe a magical sky-wizard sculpted mankind from clay. Whether this counts as "computation" depends on how "compute" is defined.
Its interesting seeing the gulf between the philosophers and the computer scientists. I think your average philosopher would enjoy a trip down the rabbit hole of automata theory and the hierarchy of things that can emulate lower levels things vs things that look different but are at the same computational level. Watching a non-CS philosopher rub a NFA up against a CFG, for example, would be interesting. What would Marx say about the assumptions of a DPDA wrt the labor theory of value (or anything else interesting?)
I can't think of a definition of "compute" that would both include analog computers, but exclude e.g. a rock thrown.<p>I'm not sure how you could argue against the fact that in a near vacuum and a fixed gravitational field, a rock thrown will compute a fairly accurate approximation of a parabola.