Why x=x ? I know that, proving 1+1=2 is hard
— Monist
Well, no, it isn't. — alcontali
Well, it was much harder for Russell and Whitehead, PA did not satisfy me for many reasons.
The starting-point rules, i.e. the system-wide premises, in a mathematical theory are always arbitrary, unexplained and unjustified beliefs. That is simply the essence of the axiomatic epistemology. — alcontali
Thank you for this reply, it helps me a lot, but does not solve my problem. Aren't axioms, self-evident assumptions? If so, when can we accept self-evident beliefs, just when they are practical? Do we have to analyse the relation between truth and practicality then?
You might only say this if somebody was trying to persuade you that x was not x but under what are the conditions might this be a possibility? — Mike Radford
Under what conditions is x=x true, when we just accept it? I might be persuaded that x=x.
It is difficult to see what is the content of the proposition, x=x is being presented to the reader. — Mike Radford
The proposition is simply: A thing resembles itself. The question is, "what is the proof?"
As with the x=x proposition it makes an assumption that numerical values remain constant — Mike Radford
Lets imagine that x is a variable, then again we end up with x=x. Thank you for your perspective.
Something is axiomatically true, we usually say, if its true by definition.
An apple is an apple because we have defined an apple as an apple.
But how do we know if a definition is correct or complete.
That is a difficult question, I would say. — Yohan
Exactly, I am trying to find a ground to stand on. Starting points known as axioms, simply suck.
:-)
Meaning auto-supposes self-identity. — jorndoe
The Law of Identity states that a certain thing is identical to itself, and I ask why.
1+1=2 is a more meaningful proposition than simply 1=1. It tells us something about the definition of each quantity in the relationship and something about the relationship itself — Mike Radford
1=1 may or may not be meaningful, but is seems to be true, but why? (It is meaningful in the sense of understanding the internal relation of any quantity; the Law of Identity)
"an apple is an apple", but why? I do not get why any certain thing called 'x', should be 'x'.
The simpler it gets, the complexer explaining it.
— Monist
I really don't get the reason why anyone would ever use that phrase, "An apple is an apple.", unless they're just playing words games, which isn't a complex thing at all.
How is using that phrase different than saying, "An apple" while pointing at an apple? Is your pointing the equivalent of = ? — Harry Hindu
Instead of 'apple' try 'thing'. Saying "a thing" while pointing at the thing does not explain why the thing identical to the thing. It does not explain the relation between the thing and the thing. x=x does, it simply tells that the thing, is itself. The point is, why?
:-)