Consciousness, then, I conclude, in its simplest acceptation, when it is understood as regarding the present only, is no distinct power of the mind, or name of a distinct class of feelings, but is only a general term for all our feelings, of whatever species these may be, sensations, thoughts, desires;--in short, all those states or affections of mind, in which the phenomena of mind consist; and when it expresses more than this, it is only the remembrance of some former state of the mind, and a feeling of the relation of the past and the present as states of one sentient substance. The term is very conveniently used for the purpose of abbreviation, when we speak of the whole variety of our feelings, in the same manner as any other general term is used, to express briefly the multitude of individuals that agree in possessing some common property of which we speak; when the enumeration of these, by description and name, would be as wearisome to the patience, as it would be oppressive to the memory. But still, when we speak of the evidence of consciousness, we mean nothing more, than the evidence implied in the mere existence of our sensations, thoughts, desires,--which is utterly impossible for us to believe to be and not to be; or, in other words, impossible for us to feel and not to feel at the same moment. This precise limitation of the term, I trust, you will keep constantly in mind in the course of our future speculations. FOOTNOTES: [41] Pope's Essay on Man, Ep. ii. v. 35-39; 19-24; and 29, 30. [42] Ad Lectorem.--A Note prefixed to the Elementa Philosophiæ. 4to. Amstelod. 1668. [43] Epist. 97. LECTURE XII. ON CONSCIOUSNESS, CONTINUED,--ON MENTAL IDENTITY,--IDENTITY IRRECONCILABLE WITH THE DOCTRINE OF MATERIALISM,--DIFFERENCE BETWEEN PERSONAL IDENTITY AND MENTAL IDENTITY,--OBJECTIONS TO THE DOCTRINE OF MENTAL IDENTITY STATED. In my last Lecture, Gentlemen, I brought to a conclusion my remarks on the _nature_ and _objects_ of _Physical Inquiry_,--the clear understanding of which seemed to me, essentially necessary before we could enter with any prospect of success, on the physiological investigation of the Mind.