Knowledge is two-fold, and consists not only in an affirmation of what is true, but in the negation of that which is false.

Knowledge is two-fold, and consists not only in an affirmation of what is true, but in the negation of that which is false.

知识是双重的，它不仅包含对真理的肯定，而且包含对谬误的否定。

-- Charles Caleb Colton 英国作家科尔顿