it is sufficient for my purpose to have it conceded that in thought properly so called, i. e., in those intellectual operations in which the deliverances of sense are digested into that system of ideal forms and relations which we call knowledge, or (what is the same thing) science, we never deal with things as they exist, or are represented as existing, objectively—that we have not, nor can we have, present to our minds the whole complement of phenomena which are the constituents of a material object, but always some one or more of them selected or "abstracted" from the rest; that being so, not only for the reason that all our thought is, in the language of Leibnitz (adopted by Herbert Spencer in the first chapter of his "First Principles"), symbolical, the attributes even of the simplest material object being too numerous to be represented in consciousness at the same time, but for the far weightier reason that our knowledge of the attributes of a material object is never complete. I may say here, incidentally, that, in asserting the abstract nature of thought, I am not taking sides in the interminable controversy between Realism and Idealism, or Presentationism and Representationism; a controversy which would be speedily ended if it came to be thoroughly understood that the phenomena of vision, which, ever since the time of Plato, have furnished nearly all the metaphors for the description of intellectual operations, present but distant analogies of the phenomena of perception, and that the puzzle about mediate and immediate perception is but the common case of the obscuration of a subject by a series of figures meant to illustrate it. In my discussion, I am only generally concerned with the fundamental relation which all our thought about objective reality bears to that reality itself.
There is, of course, no agreement among thinkers as to the nature or even the number of successive steps which lead to the formation of the elements of distinct thought. The terms most commonly employed of late (by those, at least, whose authority commands the most respect, viz., the comparative philologists, who are constrained, by the methods of their own science, to treat psychological questions inductively), to designate those steps, are Sensation, Perception, Representation, and Conception. The first two of these I shall, for the moment, leave wholly out of the account, as not relevant to the present inquiry, it being admitted on all hands that the materials of distinct thought are either representations or concepts. A representation may be generally defined as an exhibition to the mind of the deliverances of sense (if the object be real, or of the phantasy if the object be imaginary), in their empirical order and form—in other words, as a mere mental image of the object; while, in the concept, these deliverances are reduced to unity by the establishment of relations between them other than the relation of their fortuitous concurrence, the concept, at the same time, being made distinct by the establishment of relations between it and the previous concepts of the mind. If I were writing a treatise on
