When you perceive an object, already you are using two mental processes, which cannot in fact be separated, or exist the one without the other. In the first place there is simple awareness of a reality. You objectify an impression without arguing as to its reality at all, or relating it to yourself or anything else. You merely characterise the thing, and are aware of it as concrete and individual. This is the Pure Intuition. It has no admixture of intellectual process. And its salient characteristic is _that it is made or expressed by the mind_, and is indeed identical with this expression. You cannot separate the intuition from its expression. Moreover it is aesthetic in nature. Its character is identical with the character of the mind-process which makes the vision of the artist and the poet. But this intuition is at once generalised, and related. The process of generalisation is the formation of the Concept, and is characteristic of the logical or intellectual activity. Moreover the Pure Concept is universal, and expressive, belonging to all individuals; concrete, and therefore real. Pseudo-concepts, which fail either in universality, expressiveness or concreteness, do exist and are of great value, but this value belongs not to the theoretical, but to the practical, activity. ‘Evolution’ is a pure concept, ‘chair’ a pseudo-concept. For our purpose it is not necessary to elaborate this point. What does interest us is the relation between the two theoretical activities of the spirit--Intuition and Concept. They are ‘moments in the unity of a single process.’ Neither takes a prior place. “We cannot think without universalising, and we cannot have an intuition without thinking[6].” In other words, they are related in a synthesis that is _a priori_. This means that the intellectual activity which relates and generalises the intuitions or presentations does not depend upon them, but is as much a condition of experience as are the presentations themselves. Each of the two things, the intuition and the concept, is essential to knowledge; the concept is empty of content without the intuition, but you cannot have an intuition without thinking it. The two form an indivisible, organic unity; neither able to exist without the other. You cannot think without universalising, nor intuit without thinking. This is the logical _a priori_ synthesis discovered by Kant. But Croce proceeds to use it in a wider sense, as we shall see. These two elements then, the intuitional and the conceptual, together constitute the whole theoretic activity of knowing. Now the first of these elements, the intuition, is expression of a reality to the self. It is essentially aesthetic, for aesthetic is the science of expressive activity. In forming an intuition, and expressing it, we compass Beauty, for Beauty is expression. But there is another side to the activity of the spirit. Thinking and doing, willing and acting, go hand in hand.