Not that I disagree with your conclusion (or agree – mostly I’m just confused), but:
I don’t believe there is any physical system, in our brains or otherwise, that represents this function or its integral.
Including the representation in your computer, or your brain, of the phrase “the function f on the real numbers such that for any real number x, f(x) is 1 if x is irrational and f(x) is 0 otherwise”?
Ah, I should clarify that point, it is confusing as I wrote it.
I meant that there is no physical domain over which some point wise property varies discontinuously as a function of whether the point, in some measure, has a rational or irrational distance from some reference, and that the only physical systems that in any sense represent the function do so indirectly, by representing propositions about it (such as the examples you gave).
Not that I disagree with your conclusion (or agree – mostly I’m just confused), but:
Including the representation in your computer, or your brain, of the phrase “the function f on the real numbers such that for any real number x, f(x) is 1 if x is irrational and f(x) is 0 otherwise”?
Ah, I should clarify that point, it is confusing as I wrote it.
I meant that there is no physical domain over which some point wise property varies discontinuously as a function of whether the point, in some measure, has a rational or irrational distance from some reference, and that the only physical systems that in any sense represent the function do so indirectly, by representing propositions about it (such as the examples you gave).