1. _The data of thought._--When we turn to Lotze, we find that he makes a clear distinction between the presented material of thought, its datum, and the typical characteristic modes of thinking in virtue of which the datum gets organization or system. It is interesting to note also that he states the datum in terms different from those in which the antecedents of thought are defined. From the point of view of the material upon which ideas exercise themselves, it is not coincidence, collocation, or succession that counts; but gradation of degrees in a scale. It is not things in spatial or temporal grouping that are emphasized, but qualities as mutually distinguished, yet classed--as differences of a common somewhat. There is no inherent inconceivability in the idea that every impression should be as incomparably different from every other as sweet is from warm. But by a remarkable circumstance such is not the case. We have series, and networks of series. We have diversity of a common--diverse colors, sounds, smells, tastes, etc. In other words, the datum is sense-qualities which, fortunately for thought, are given arranged, as shades, degrees, variations, or qualities of somewhat that is identical.[21] All this is given, presented, to our ideational activities. Even the universal, the common-color which runs through the various qualities of blue, green, white, etc., is not a product of thought, but something which thought finds already in existence. It conditions comparison and reciprocal distinction. Particularly all mathematical determinations, whether of counting (number), degree (more or less), and quantity (greatness and smallness), come back to this peculiarity of the datum of thought. Here Lotze dwells at considerable length upon the fact that the very possibility, as well as the success, of thought is due to this peculiar universalization or _prima facie_ ordering with which its material is given to it. Such pre-established fitness in the meeting of two things that have nothing to do with each other is certainly cause enough for wonder and congratulation.