[madez]

> Debugging is twice as hard as writing the code in the first place. Therefore, if you write the code as cleverly as possible, you are, by definition, not smart enough to debug it.

The expression "by definition" is misplaced here. The first proposition "Debugging is twice as hard as writing the code in the first place" is not a definition. At best, we can treat it as an axiom. In any case, the conclusion "if you write the code as cleverly as possible, you are not smart enough to debug it" does not follow by definition.

[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.