Gee, I come to the opposite conclusion. If we define what can be computed as what can be computed as a TM then we are TM's, that is, computers. I understand Searle to instead be offering an argument that humans are not TM's, that there is an aspect of computing in the world that is not captured by the definition that Turing gave, and it is whatever is involved in understanding.
But the argument, as I hear it, concludes with something like "and it is obviously wrong to think this is what we are doing when we feel we understand something." That's not obvious, to me.
> some vulgar symbolic computation
I guess I still don't get it. I've not seen any evidence that what goes on between my ears is not doable this way, but I am very ready to concede that the jury is still out. I just don't understand the part where Searle says "obvious."
I'm sorry, I'm not understanding. Are you asking if a person should look for types of computation that are more powerful then Turing machines? If so, I agree, you should.
We're not even Turing machines. The Bekenstein Bound establishes humans as finite state automata.
> Human brain could be, in fact, a digital computer, but the mind in it is not a result of some vulgar symbolic computation, but a result of some mysterious computational process, that very possibly has nothing to do with manipulations with some abstract symbols.
So a magical computer? What purpose in a brains computation does the magic serve exactly?
No, that's not what's meant at all. Searle is making a distinction between syntax and semantics, where computers process only syntax (symbols are meaningless tokens), but humans can reason semantically, where propositions carry meaning. Both perform symbol processing, so "symbolic computation" is not a useful distinction here.
Further, Searle is asserting that semantics cannot arise from syntax. But this is clearly false, as various methods of computational induction demonstrate: given only syntactic analysis of output bits, you can build a semantic model to predict subsequent bits.
So what gives the symbols of the semantic model meaning? The correspondence of each symbol to real, observable objects.
> Until we learn why it happens in that type of matter, we would not be able to recreate minds.
You're assuming that consciousness requires some special property of matter. There's no justification for this assumption.
Furthermore, you are arguing that we cannot create something that we do not fully understand. This too seems false. We created fire long before we understood it, for instance.
Not sure about that.
> So what gives the symbols of the semantic model meaning? The correspondence of each symbol to real, observable objects.
And what decides what symbol corresponds to what real object?
> You're assuming that consciousness requires some special property of matter. There's no justification for this assumption.
Really? I thought that is something we have agreed upon. You are claiming that any system structured as a digital computer (hence, has a special property) is conscious, I am saying that it is not enough, it has to be structured some special way.
> We created fire long before we understood it, for instance.
This is a laughable argument. "We reproduce (as living beings do). therefore we create minds".
Nowhere did I make that claim. You're clearly confused about the arguments being made so I suggest your reread this thread.
> And what decides what symbol corresponds to what real object?
An inductive inference algorithm, like I said.
> This is a laughable argument. "We reproduce (as living beings do). therefore we create minds".
Exactly right. Therefore your claim that we must understand something before we can make it is trivially incorrect.
But that was not my point. Digital computers could be, in principle, conscious, but the idea that you can construct a mind by making a symbolic program is flawed. Human brain could be, in fact, a digital computer, but the mind in it is not a result of some vulgar symbolic computation, but a result of some mysterious computational process, that very possibly has nothing to do with manipulations with some abstract symbols.