The true key to the sophistry is, as I have already said, that it assumes a false test of identity, borrowed, indeed, from the obvious appearances of the material world, but from these obvious appearances only. Because diversity of any kind seems, in these familiar cases, to be inconsistent with absolute identity, we draw hastily the _universal_ conclusion, that it is inconsistent with absolute identity in any case. Paradoxical as the assertion may appear, however, we may yet safely assert, that, not in mind only, but, as we shall find, in matter also; some sort of diversity is so far from being inconsistent with absolute identity, that there is scarcely a single moment, if, indeed, there be a single moment, in which every atom in the universe is not constantly changing the tendencies that form its physical character, without the slightest alteration of its own absolute identity; so that the variety of states or tendencies of the same identical mind, in joy and sorrow, ignorance and knowledge, instead of being opposed, as you might think, by the general analogy of nature, is in exact harmony with that general analogy. It is from our view of _matter_, unquestionably, as implying, in all its visible changes of state, some loss of identity, some addition or subtraction of particles, or change of their form of combination, that the objection, with respect to the identity of the _mind_, during its momentary or lasting changes of state, is derived; and yet we shall find, that it is only when we consider even matter itself superficially and slightly, that we ascribe the changes which take place in it, to circumstances that affect its identity. To view it more profoundly and accurately, is to observe, even in matter, constant changes of state, where the identity has continued entire, and changes as opposite, as those of the mind itself, when, at different periods, it presents itself in different aspects, as sad and cheerful, ignorant and wise, cruel and benevolent. The apparent mystery of the continued identity of one simple and indivisible mind, in all the variety of states, of which it is susceptible, is thus in a great measure, solved, when we find this union of variety and sameness to be the result of a law that is not limited to our spiritual being, but extends to the whole universe, or at least to every thing which we know in the universe. It can no longer appear to us peculiarly wonderful, that the mind should exist at different moments in opposite states, and yet be the same in its own absolute nature, when we shall find that this compatibility is true of every atom around us, as much as of the mind itself. LECTURE XIV. CONTINUATION OF THE ANSWER TO OBJECTIONS AGAINST THE DOCTRINE OF MENTAL IDENTITY.