We call an attitude "critical" which makes itself master of the laws of its own activity in order to know how far it can rely on them and what are their limits. Theory of Knowledge can be nothing if not a critical science. Its object is precisely the most subjective activity of man--knowing. What it aims at exhibiting is the laws to which knowing conforms. Hence, the naïve attitude is wholly excluded from this science. Its claim to strength lies precisely in that it achieves what many minds, interested in practice rather than in theory, pride themselves on never having attempted, viz., "thinking about thought." IV THE STARTING-POINTS OF THE THEORY OF KNOWLEDGE At the beginning of an epistemological inquiry we must, in accordance with the conclusions we have reached, put aside everything which we have come to know. For, knowledge is something which man has produced, something which he has originated by his activity. If the Theory of Knowledge is really to extend the light of its explanation over the whole field of what we know, it must set out from a point which has remained wholly untouched by cognitive activity--indeed which rather furnishes the first impulse for this activity. The point at which we must start lies outside of what we know. It cannot as yet itself be an item of knowledge. But we must look for it immediately prior to the act of cognition, so that the very next step which man takes shall be a cognitive act. The method for determining this absolutely first starting-point must be such that nothing enters into it which is already the result of cognitive activity.