But I'm not quite clear what it means to "produce" a number. It's not as if we say to ourselves "I need another number here" and so instigate the procedure. Does your procedure create the numbers it produces from scratch or does it just produce another copy of the number???? — Ludwig V
Eh. A procedure, as I'm using the term here, accepts some input and yields some output. You show me a natural number, and I can show you another.
What I was suggesting was that we can
replace our pre-theoretical understanding of counting with this system, consisting of exactly two rules (that 1 is a natural number, and every natural number has a successor), and we will (a) lose nothing, and (b) gain considerably in convenience for doing things that build on counting.
I consider (a) and (b) more or less facts, but there's nothing wrong with examining them closely. Philosophy spends a lot of time doing exactly this sort of thing, but not only philosophy. Linguistics is an easy example quite nearby, where people want to describe a great mass of complex behavior in terms of a smallish set of rules that could account for it. A more or less universal scientific impulse.
So the "axiomatization" of counting here is open to criticism, and I believe it will withstand it.
But it doesn't necessarily tell you what counting actually is.
It might. In a sense, when you come up with a little set of rules like this, if it works pretty well, then what you definitely have is a model of the behavior you want to understand. Whether that model reflects the underlying mechanisms of the behavior, or only simulates the behavior itself, relying on different mechanisms, that's not always perfectly clear. (In one formulation of Chomsky's program, it was of the utmost importance that you have a finite system of rules that can, through recursion, generate an infinite number of sentences, because the system has to be instantiated in a human brain.)
I've been thinking a little, as we've gone along, about the most famous "primitive" counting systems, the "1, 2, 3, many" type. Is "many" a number there? Not exactly. Is it open-ended enough that it might even apply to endless or unbounded sequences? Maybe, maybe not. What I'm trying to say is it might not be quite the same thing as us saying "1, 2, 3, 4 or more" or "1, 2, 3, more than 3", because in our system of counting numbers there is definitely no upper bound.
I suppose I'm bringing that up because we might ask whether people using one counting system are doing something psychologically different from people using another, but we might also ask if there is some difference that philosophy ought to be interested in. The latter, I suppose, would be something about the system itself, and the thoughts that it enables or doesn't, and therefore what would be available as truth, given such a system.