Diversity has, like Identity, been transformed into a maxim: 'Everything is various or different': or,'There are no two things completely like each other.' Here Everything is put under a predicate, which is the reverse of the identity attributed to it in the first maxim; and therefore under a law contradicting the first. However there is an explanation. As the diversity is supposed due only to external comparison, anything taken _per se_ is expected and understood always to be identical with itself, so that the second law need not interfere with the first. But, in that case, variety does not belong to the something or everything in question: it constitutes no intrinsic characteristic of the subject: and the second maxim on this showing does not admit of being stated at all. If, on the other hand, the something _itself_ is as the maxim says diverse, it must be in virtue of its own proper character: but in this case the specific difference, and not variety as such, is what is intended. And this is the meaning of the maxim of Leibnitz. When understanding sets itself to study Identity, it has already passed beyond it, and is looking at Difference in the shape of bare Variety. If we follow the so-called law of Identity, and say,--The sea is the sea, The air is the air, The moon is the moon, these objects pass for having no bearing on one another. What we have before us therefore is not Identity, but Difference. We do not stop at this point however, or regard things merely as different. We compare them one with another, and thus discover the features of likeness and unlikeness. The work of the finite sciences lies to a great extent in the application of these categories, and the phrase 'scientific treatment' generally means no more than the method which has for its aim comparison of the objects under examination. This method has undoubtedly led to some important results;--we may particularly mention the great advance of modern times in the provinces of comparative anatomy and comparative linguistic. But it is going too far to suppose that the comparative method can be employed with equal success in all branches of knowledge. Nor--and this must be emphasised--can mere comparison ever ultimately satisfy the requirements of science. Its results are indeed indispensable, but they are still labours only preliminary to truly intelligent cognition.