Before Hume, rationalists had held that effect could be deduced from cause; Hume argued that it could not and from this inferred that nothing at all could be known "a priori" in relation to cause and effect. Kant, who was brought up under the auspices of rationalism, was deeply disturbed by Hume's skepticism. "I freely admit that it was the remembrance of David Hume which, many years ago, first interrupted my dogmatic slumber and gave my investigations in the field of speculative philosophy a completely different direction."