Once again, I don’t know anything about math. But my impression is, the axioms are not invented out of nowhere. They are taken from what we consider self-evident. And then, you can take one axiom, like Lobachevsky did with the parallel straights, and experiment with twisting or reversing it. It is not the same as making a new axiom out of nowhere.
Do you think that “1 + 1 = 2” is self evident? Or that “a * b = b * a” is self evident? Many people would assert that they are. But they are wrong. In regular arithmetic it is true that “1 + 1 = 2” … but in Boolean arithmetic “1 + 1 = 1”. And in vector / matrix algebra the multiplication is not commutative. It is quite possible that “b * a” cannot even be
defined.
We are
free to propose any set of axioms, as long as they are non-contradictory. Sure, the usual axioms are easy to accept, since they reflect the physical reality. Of course in “Christian mathematics” it is asserted that “one equals three” (Trinity).
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And in “Christian geometry” one is able to sit on the right side of himself (recall the “Apostles creed”).
Of course!, you can also write a novel, or a poem; but no one will ever suppose that it might have been the product of a deduction process, based on a set of axioms and some transformation rules.
Quite true, but to those people who assert the existence of “abstract objects” it does not matter. For them the chromatic scale or the language “exists” independently of humans. Looks like you disagree with them, which is promising.
However there are other “made up” imaginary constructs, like games, mathematical or otherwise. The rules of chess - for example - are “created”, ex nihilo.
It has happened that the number “Pi” was discovered (not invented, as anyone who study calculus come to know) within the system of Euclidean geometry.
Except that the concepts of dot, lines, circles, planes etc. are all “invented”, as
abstractions of some real life objects. It was Plato’s nonsensical idea that “abstractions” exist primarily and the real world objects are merely crude approximations of the “ideal” abstractions". I would love to go back in time and ask him how does the “ideal” excrement look or smell like.
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Too bad I cannot do it.
It has a very specific value and does not depend on anything else. “Pi” has the same value in whichever geometrical system you might conceive. If from one system to another the relation between the perimeter of a circumference and its diameter is not the same as in another system, that has nothing to do with the value of “Pi”.
So we “declare” that we shall call the value of 4 * (1 - 1/3 + 1/5 - 1/7 + 1/9…) to be “PI” and
it just so happens that in the Euclidean geometry it
happens to describe the ratio between the circumference of the circle and its diameter? I have no problem with that approach. For the fun of it, browse the different series for calculating the value of “PI”…
mathworld.wolfram.com/PiFormulas.html
On the other side, I agree with you that “Pi” (and every other relation), did not exist before a mind could establish it (not invented!); but these kind of mental or ideal objects have a very peculiar mode existence: They are objective in the sense that they rule over any mind; and it is in this very same sense that they are not invented -as I have said-, but discovered. We can certainly invent some mathematical elements, but not the relations between them.
Once you
invent those new concepts,
and the relationships between them, you have a new system, and then you can
discover the intricacies of it. Those are the results of the concepts and the relationships. We create the system and then we study it and discover the details.
Just ponder how many different games can you create by using the standard chess set of the standard chess board. But as soon as you select one of them, you “merely” discover the possible chess games, or problems.
Looks like that our point of view is not divergent, after all. (Of course I could be wrong, as always).