We've seen that the principles of reason derive from the nature of the mind itself. This means that if we succeed in grasping the nature of the mind – its essence – we might deduce directly from it all the principles of reason. What's the essence of the mind? Briefly, the need for unity or simplicity. For the mind is simple and understands well only that which is also simple. We understand geometric figures best, because these are composed only of homogeneous space. The mind's need for simplicity is so great that when it examines any more concrete object – necessarily multiple and complex in nature – it has to conceive of it as though it were simple. The mind never renders these objects simply as geometric figures, of course, but it's compelled to introduce a certain unity and order. So we can say that the aim of the laws of the mind is precisely to introduce this order and unity. Does this order demanded by the mind really exist in things themselves? We won't try to answer this question now. But whatever the answer, such order is clearly required by the nature of the mind.

The principles of reason thus introduce order into our knowledge. But what are these principles? Without imagining that we can do so in an utterly deductive way, we'll try to identify them now.

What's given is multiple, and what the mind wants is to impose upon it some kind of order.