[hinkley]

I promised myself I was going to stop getting sucked into pedantry.

I believe that the sense in which he meant 'by definition' is that it's tautological to say that more of something is more than less of something.

For n > 0, 2n > n

[madez]

The meaning of what the quote is saying is clear. It is also clear how the logical reasoning is supposed to be. My - admittedly pedantic - point is that the choice of words is incorrect.