Two sorts of truth: profound truths recognized by the fact that the opposite is also a profound truth, in contrast to trivialities where opposites are obviously absurd.

Unsourced variant: The opposite of a correct statement is a false statement. But the opposite of a profound truth may well be another profound truth. | As quoted in Max Delbrück, Mind from Matter: An Essay on Evolutionary Epistemology, (1986) p. 167. It is the hallmark of any deep truth that its negation is also a deep truth