Werner Heisenberg.
Physics and Beyond.
Allen & Unwin. 1971
Translated from the German Der Teil und das Ganze by Arnold J. Pomerans
In Chapter 8, "Atomic Physcics and Pragmatism (1929)":
p102.
And so both our formulations contained a
large grain of truth, and Paul and I could console ourselves with an
oft-repeated dictum of Niels Bohr: "The opposite of a correct
statement is a false statement. But the opposite of a profound truth may
well be another profound truth."