We need to be absolutely clear that this creative activity must, in its turn, be given to us in all its immediacy. No inferences must be required in order to know that it occurs. Thence it follows, at once, that sense-data do not meet our requirement. For, the fact that they do not occur without our activity is known to us, not immediately, but as an inference from physical and physiological arguments. On the other hand, we do know immediately that it is only in and through the cognitive act that concepts and ideas enter into the sphere of the Immediately-Given. Hence, no one is deceived concerning the character of concepts and ideas. It is possible to mistake a hallucination for an object given from without, but no one is ever likely to believe that his concepts are given without the activity of his own thinking. A lunatic will regard as real, though they are in fact unreal, only things and relations which have attached to them the predicate of "actuality," but he will never say of his concepts and ideas that they have come into the world without his activity. Everything else in our world-picture is such that it must be given, if it is to be experienced by us. Only of our concepts and ideas is the opposite true: they must be produced by us, if they are to be experienced. They, and only they, are given in a way which might be called intellectual intuition. Kant and the modern philosophers who follow him deny altogether that man possesses this kind of intuition, on the ground that all our thinking refers solely to objects and is absolutely impotent to produce anything out of itself, whereas in intellectual intuition form and matter must be given together. But, is not precisely this actually the case with pure concepts and ideas? [48] To see this, we must consider them purely in the form in which, as yet, they are quite free from all empirical content. In order, e.g., to comprehend the pure concept of causality, we must go, not to a particular instance of causality nor to the sum of all instances, but to the pure concept itself. Particular causes and effects must be discovered by investigation in the world, but causality as a Form of Thought must be created by ourselves before we can discover causes in the world. If we hold fast to Kant's thesis that concepts without percepts are empty, it becomes unintelligible how the determination of the Given by concepts is to be possible. For, suppose there are given two items of the world-content, a and b. In order to find a relation between them, I must be guided in my search by a rule of determinate content. Such a rule I can only create in the act of cognition itself. I cannot derive it from the object, because it is only with the help of the rule that the object is to receive its determinations. Such a rule, therefore, for the determination of the real has its being wholly in purely conceptual form.