Who said (a variation of) this? "Mathematics didn't teach me how to reason correctly, but [...] how easy it is to make an error when reasoning."

Question

I remember I once read a quote of a mathematician at the beginning of a book, or article, which said a (possibly) small variation of:

Mathematics didn't teach me how to reason correctly, but at least it taught me how easy it is to make an error when reasoning.

Does anybody knows who said this?

Answer 1

Harald Bohr is credited with saying that
If mathematics does not teach us how to think correctly, it at least teaches us how easy it is to think incorrectly.

I couldn't find an "official attribution" but I trust Gert K. Pedersen, who quotes it in the 'Preface to the Second Printing' of his book "Analysis Now" (Springer, GTM 118, Revised printing 1995).