" Again, there are truths which cannot be denied without doing violence to the laws of our nature. In such cases the denial is forced, and can only be temporary. The laws of our nature are sure sooner or later to assert themselves, and constrain an opposite belief. A pendulum when at rest hangs perpendicularly to the horizon. It may by extraneous force be made to hang at any degree of inclination. But as soon as such force is removed, it is sure to swing back to its normal position. Under the control of a metaphysical theory, a man may deny the existence of the external world, or the obligation of the moral law; and his disbelief may be sincere, and for a time persistent; but the moment the speculative reasons for his disbelief are absent from his mind, it of necessity reverts to its original and natural convictions. It is also possible that a man's hand may be so hardened or cauterized as to lose the sense of touch. But that would not prove that the hand in man is not normally the great organ of touch. "

― Charles Hodge ,