This post is a followup to "We are not living in a simulation" and intended to help me (and you) better understand the claims of those who took a computationalist position in that thread. The questions below are aimed at you if you think the following statement both a) makes sense, and b) is true:
"Consciousness is really just computation"
I've made it no secret that I think this statement is hogwash, but I've done my best to make these questions as non-leading as possible: you should be able to answer them without having to dismantle them first. Of course, I could be wrong, and "the question is confused" is always a valid answer. So is "I don't know".
- As it is used in the sentence "consciousness is really just computation", is computation:
a) Something that an abstract machine does, as in "No oracle Turing machine can compute a decision to its own halting problem"?
b) Something that a concrete machine does, as in "My calculator computed 2+2"?
c) Or, is this distinction nonsensical or irrelevant? - If you answered "a" or "c" to question 1: is there any particular model, or particular class of models, of computation, such as Turing machines, register machines, lambda calculus, etc., that needs to be used in order to explain what makes us conscious? Or, is any Turing-equivalent model equally valid?
- If you answered "b" or "c" to question 1: unpack what "the machine computed 2+2" means. What is that saying about the physical state of the machine before, during, and after the computation?
- Are you able to make any sense of the concept of "computing red"? If so, what does this mean?
- As far as consciousness goes, what matters in a computation: functions, or algorithms? That is, does any computation that give the same outputs for the same inputs feel the same from the inside (this is the "functions" answer), or do the intermediate steps matter (this is the "algorithms" answer)?
- Would an axiomatization (as opposed to a complete exposition of the implications of these axioms) of a Theory of Everything that can explain consciousness include definitions of any computational devices, such as "and gate"?
- Would an axiomatization of a Theory of Everything that can explain consciousness mention qualia?
- Are all computations in some sense conscious, or only certain kinds?
ETA: By the way, I probably won't engage right away with individual commenters on this thread except to answer requests for clarification. In a few days I'll write another post analyzing the points that are brought up.
I don't know the answer to any of these questions, and I don't know which of them are confused.
Here's a way to make the statement "consciousness is computation" a little less vague, let's call the new version X: "you can simulate a human brain on a fast enough computer, and the simulation will be conscious in the same sense that regular humans are, whatever that means". I'm not completely sure if X is meaningful, but I assign about 80% probability to its being meaningful and true, because current scientific consensus says individual neurons operate in the classical regime, they're too large for quantum effects to be significant.
But even if X turns out to be meaningful and true, I will still have leftover object-level questions about consciousness. In particular, knowing that X is true won't help me solve anthropic problems until I learn more about the laws that govern multiple instantiations of isomorphic conscious thingies, whatever that means. Consciousness could "be" one instantiated computation, or an equivalence class of computations, or an equivalence class plus probability-measure, or something even more weird. I don't believe we can enumerate all the possibilities today, much less choose one.