Indeed, it is never by any other means than by his senses, that beings become known to man, or furnish him with ideas; it is only in consequence of the impulse given to his body, that his brain is modified, or that his soul thinks, wills, and acts. If, as ARISTOTLE asserted more than two thousand years ago,--"_nothing enters the mind of man but through the medium of his senses_,"--it follows as a consequence, that every thing that issues from it must find some sensible object to which it can attach its ideas, whether immediately, as a man, a tree, a bird, &c. or in the last analysis or decomposition, such as pleasure, happiness, vice, virtue, &c. This principle, so true, so luminous, so important in its consequence, has been set forth in all its lustre, by a great number of philosophers; among the rest, by the great LOCKE. Whenever, therefore, a word or its idea does not connect itself with some sensible object to which it can be related, this word or this idea is unmeaning, and void of sense; it were better for man that the idea was banished from his mind, struck out of his language: this principle is only the converse of the axiom of ARISTOTLE,--"_if the direct be evident, the inverse must be so likewise_." How has it happened, that the profound LOCKE, who, to the great mortification of the metaphysicians, has placed this principle of ARISTOTLE in the clearest point of view? how is it, that all those who, like him, have recognized the absurdity of the system of innate ideas, have not drawn the immediate, the necessary consequences? How has it come to pass, that they have not had sufficient courage to apply so clear a principle to all those fanciful chimeras with which the human mind has for such a length of time been so vainly occupied? did they not perceive that their principle sapped the very foundations of those metaphysical speculations, which never occupy man but with those objects of which, as they are inaccessible to his senses, he consequently can never form to himself any accurate idea? But prejudice, when it is generally held sacred, prevents him from seeing the most simple application of the most self-evident principles. In metaphysical researches, the greatest men are frequently nothing more than children, who are incapable of either foreseeing or deducing the consequence of their own data.