Page:Supplement to the fourth, fifth, and sixth editions of the Encyclopaedia Britannica - with preliminary dissertations on the history of the sciences - illustrated by engravings (IA gri 33125011196181).pdf/157

Rh mended, furnished of itself a strong argument against the soundness of his doctrines. The proper answer to this objection does not seem to have occurred to him; nor, so far as I know, to any of his successors;—that the abstractions of the understanding are totally different from the abstractions of the imagination; and that we may reason with most logical correctness about things considered apart, which it is impossible, even in thought, to conceive as separated from each other. His own speculations concerning the indissolubility of the union established in the mind between the sensations of colour and the primary qualities of extension and figure, might have furnished him, on this occasion, with a triumphant reply to his adversaries; not to mention that the variety of metaphors, equally fitted to denote the same intellectual powers and operations, might have been urged as a demonstrative proof, that none of these metaphors have any connection with the general laws to which it is the business of the philosopher to trace the mental phenomena.

When Descartes established it as a general principle, that nothing conceivable by the power of imagination, could throw any light on the operations of thought (a principle which I consider as exclusively his own), he laid the foundation-stone of the Experimental Philosophy of the Human Mind. That the same truth had been previously perceived more or less distinctly, by Bacon and others, appears probable from the general complexion of their speculations; but which of them has expressed it with equal precision, or laid it down as a fundamental maxim in their logic? It is for this reason, that I am disposed to date the origin of the true Philosophy of Mind from the Principia of Descartes rather than from the Organon of Bacon, or the Essay of Locke; without, however, meaning to compare the French author with our two countrymen, either as a contributor to our stock of facts relating to the intellectual phenomena, or as the author of any important conclusion concerning the general laws to which they may be referred. It is mortifying to reflect on the inconceivably small number of subsequent inquirers by whom the spirit of this cardinal maxim has been fully seized; and that, even in our own times, the old and inveterate prejudice to which it is opposed, should not only have been revived with success, but should have been very generally regarded as.an original and profound discovery in metaphysical science. These circumstances must plead my apology for the space I have assigned to the Cartesian Metaphysics in the crowded historical picture which I am at present attempting to sketch. The fulness of illustration which I have bestowed on the works of the master, will enable me to pass over those of his disciples, and even of his antagonists, with a correspondent brevity.