Quote Originally Posted by Xei View Post
Read my post closer, I went to a lot of length explaining this... I was not asking for proof of '0 + 5 = 5', I was asking for proof of '0 + x = x'. If you thought I would ever ask for proof of the former then the message of my post totally went over your head; please try to read it with more concentration.

This has nothing to do with Philosopher's post by the way; he was just making the point that many people can't cope with simple abstraction. I was elaborating way beyond that, Phil probably doesn't even agree with me.
I read it a few times to make sure I was getting it right.
But 0 + x = x is just an abstraction. It doesn't mean anything by itself.
So all you have to do is substitute the x for a number of something.
And see if it is correct. Then you have proven it.

If you mean you can't prove it without doing that - being tautological - well that doesn't mean anything either