This wonderful mistake may possibly have arisen from hence; that to be endued with consciousness is inseparable from the idea of a person, or intelligent being. For, this might be expressed inaccurately thus, that consciousness makes personality: and from hence it might be concluded to make personal identity. But though present consciousness of what we at present do and feel is necessary to our being the persons we _now are_; yet present consciousness of past actions or feelings is not necessary to our being the same persons who performed those actions, or _once had_ those feelings. The inquiry, what makes vegetables the same, in the common acceptation of the word, does not appear to have any relation to this of personal identity: because, the word _same_, when applied to them and to a person, is not only applied to different subjects, but it is also used in different senses. For when a man swears to the same tree, as having stood fifty years in the same place, he means only the same as to all the purposes of property, and uses of common life; and not that the tree has been all that time the same, in the strict philosophical sense of the word. For he does not know, whether any one particle of the present tree be the same with any one particle of the tree which stood in the same place fifty years ago. And if they have not one common particle of matter, they cannot be the same tree in the proper philosophic sense of the word _same_: it being evidently a contradiction in terms, to say they are, when no part of their substance, and no one of their properties is the same: no part of their substance, by the supposition; no one of their properties, because it is allowed, that the same property cannot be transferred from one substance to another. Therefore when we say the identity of sameness of a plant consists in a continuation of the same life, communicated under the same organization, to a number of particles of matter, whether the same or not; the word _same_, when applied to life and to organization, cannot possibly be understood to signify, what it signifies in this very sentence, when applied to matter. In a loose and popular sense then, the life and the organization and the plant are justly said to be the same, notwithstanding the perpetual change of the parts. But in strict and philosophical language, no man, no being, no mode of being, no any thing, can be the same with that, with which it has indeed nothing the same. Now sameness is used in this latter sense, when applied to persons. The identity of these, therefore, cannot subsist with diversity of substance.