The identity is no longer complete, no longer absolute, because there is no longer, as in the case of spiritual existence, absolute sameness of essence. Of the complex being under consideration, animal or vegetable, the life-principle is, indeed, one and the same throughout all periods of its existence, but the material organization retains not the same absolute essence, only the same general structure, and form, and adaptation of parts, while the parts and particles themselves are continually changing. It is only in a modified and partial sense, then, not in strict philosophical use of language, that we can predicate identity of any material organic existence. We mean by it, simply, _continuity of life_ under the same general structure and organization; for so far as it has unity at all, this is it. This enables us to distinguish such an object from any and all other like objects of the same kind or sort. _3. Identity as applied to the third Class._--As regards mere inorganic matter, its identity consists, again, in its absolute oneness and sameness. There must be no change of particles, for the essence of the thing now considered lies not in any peculiarity of form, or structure, or life-principle, all which are wanting, but simply in the number and nature of the particles that make up the mass or substance of the thing, and if these change in the least, it is no longer the same essence. There is, properly, then, no such thing as identity in the cases now under consideration, since the particles of any material substance are liable to constant changes. It is only in a secondary and popular sense that we speak of the identity of merely inorganic material substance; strictly speaking, it has no identity, and continues not the same for any two moments. We say, however, of two pieces of paper, that they are of the _same_ color, meaning that they are both white or both red; of two coins, that they are of the same fineness, the same size, and weight, etc., meaning, thereby, only that the two things are of the same _sort_ of color, the same degree of fineness, etc., and not that the color of the one or the fineness and size of the one is absolutely the essential and identical color, size, fineness of the other. It is by a similar use of terms, not in their strict and proper, but in a loose and secondary sense, that we speak of the identity or sameness of any material substance in itself considered. Strictly, it has no identity unless its substance is absolutely unchanged, which is not true of most, if, indeed, of any material existence, for any successive periods of time.