_This not absolute Identity._--In the cases now under consideration, in which, in popular language, objects are termed "same" and "identical," which are not strictly so, there is _comparative_ rather than _absolute_ unity and identity. There is reference always in such cases to other objects of the same kind, sort, and description, a series of which the object of present cognition is one, and to which series it holds the same relation now that it held formerly. As when, of several books on a table, you touch _one_, and after the interval of some moments or hours touch the same again; you say, The book I last touched is the same I touched before, the _identical_ one; you do not mean that its _substance_ is absolutely unchanged, that it has the same precise number of particles in its composition as before--this is not in your mind at all--but only that the unity thus designated is the same unity previously designated, that, and not some other one of the series of similar objects. It is a _comparative_ idea, a comparative identity, in which numerical unity is the element chiefly regarded. _Possible Plurality implied._--In all cases where the idea of identity arises in the mind, there is implied a _possible_ plurality of objects of the same general character; the idea of such diversity or plurality is before the mind, and the foundation of that idea is the difference of cognition. The same object is viewed by the same person at _different times_ or by _different persons_ at the same time, and in that case, though the object itself should be absolutely one and the same, yet there have been distinct, separate cognitions of it, and this plurality or difference of cognition is a sufficient foundation for the idea of a possible diversity of object. The book _as known_ to-day and the book _as known_ yesterday, are two distinct objects of thought. The cognition now, and the cognition then, are two separate acts of the mind; and the question arises, Are the _objects_ distinct, as well as the cognitions? This is the question of identity. You have an immediate, irresistible conviction that the object of these several cognitions is one and the same. You affirm its identity, absolute or comparative, as the case may be.