### Judgment cannot be a computation

Reader rob contends that "surely" when we judge that a computer is running algorithm A correctly, we are using an algorithm ourselves (let's call it B) to make that judgment.

But that can't possibly be right. Because, if judgment is just an algorithm, to have any confidence at all that algorithm B judged algorithm A's performance correctly, we would have to run algorithm C to check algorithm B. And then we would have to check algorithm C with algorithm D. And so on, ad infinitum.

So, either:

1) Judgment is itself algorithmic, and we really have no idea if any algorithm at all is correct, because we will always eventually wind up at the top of our stack with some completely unchecked algorithm, and so we will have no reason to suspect that any of the other algorithms were correct either.

Or:

2) Human judgement is not algorithmic in character.

Of course, I am far from the first person to note this. And here is a lengthier discussion of this point.

PS: Reader rob was at least intelligent enough to suspect that this complete and total defeat of his position was on its way. And he tried to dodge it by positing a top-level, "heuristic" algorithm that is "good enough" for practical purposes, even though we should have no ultimate confidence in it. But what could "good enough" mean in a purely material world: it could not mean anything more than that "the pieces of matter that happen to run algorithm X have so far survived." There is no reason whatsoever to think that the results of these algorithms are "true" in any sense beyond, "Well, the machine running it is still here!" In particular, look at what this does to all arguments for materialism: we have no way of judging if they are true, since the algorithm we might use to "check" that has not itself been "checked." And if we count sheer numbers, the number of people who run the "materialism is true" algorithm have been vastly outnumbered by those running the "materialism is false" algorithm, and as soon as some society is "infected" by the materialism-is-true algorithm, they rapidly give up hope, their birth rate plummets, and they disappear from the earth. So judged by what rob concedes is, on his view, the only possible measure of success, materialism is a complete failure.