So much, indeed, of human knowledge, and of all that is valuable and delightful in human feeling, involves these elementary sensations, as it were in the very essence of the thoughts and feelings themselves, that one of the most acute of modern French metaphysicians, and, with scarcely an exception, all the philosophers of the French metaphysical school, who are his followers, have considered the whole variety of human consciousness, as mere sensation variously transformed; though, in stating the nature of this transformation, and the difference of the sensations as transformed from the primary forms of mere external feeling, they have not been so explicit, as the assertors of a system so paradoxical ought assuredly to have been. On the fallacies of this very prevalent theory of mind, however, which is afterwards to be examined by us fully, I need not at present make any remarks. Though this excessive simplification of the phenomena of human thought and feeling is, however, far more than the phenomena truly allow, it is not the less certain, that all the varieties of our consciousness, though not mere _transformations_ of external sense, are, when traced to their source, the _results_ of sensation, in its various original forms. In inquiring into the phenomena of our senses, then, we begin our inquiry, where knowledge itself begins, and though the twilight, which hangs over this first opening of intellectual life, is perhaps only a presage, or a part of that obscurity which is to attend the whole track of human investigation, it still is twilight only, not absolute darkness. We can discover _much_, though we cannot discover _all_; and where absolute _discovery_ is _not_ allowed, there is still left to us a probability of conjecture, of which, in such limited circumstances, even philosophy may justly avail herself, without departing from her legitimate province. FOOTNOTES: [63] Œuvres, tom. ii. p. 12. [64] P. 131. [65] Pleasures of Imagination, Book III. v. 493--514. The fixed soul, v. 505. Exploits, v. 508; and Spells, v. 509. _Orig._ [66] On the Intellectual powers, Essay II. c. 16. [67] Lib. I. v. 18-25. and 28-31. LECTURE XIX. BRIEF NOTICE OF THE CORPOREAL PART OF THE PROCESS, IN SENSATION.