acknowledged shows that to mankind in general, at any rate, they are not axiomatic, and that, however clear and convincing the reasons for them may be, at all events those reasons require to be stated. It was this determined and vigorous protest against multiplying assumptions and attempting to withdraw a vast mass of propositions, both speculative and practical, from the control and revision of reason, that, perhaps, constituted the most distinctive and valuable part of Locke's teaching. * * * * * Having cleared from his path the theory of Innate Principles, Locke proceeds, in the Second Book, to inquire how the mind comes to be furnished with its knowledge. Availing himself of a metaphor which had been commonly employed by the Stoics, but which reaches as far back as Aristotle and Plato, and even as Æschylus, he compares the mind to "white paper, void of all characters, without any ideas," and then asks: "Whence comes it by that vast store, which the busy and boundless Fancy of Man has painted on it, with an almost endless variety? Whence has it all the materials of Reason and Knowledge? To this I answer in one word, from _Experience_: In that all our knowledge is founded; and from that it ultimately derives itself. Our observation employed either about external or sensible objects, or about the internal operations of our minds perceived and reflected on by our selves, is that which supplies our Understandings with all the materials of thinking. These two are the Fountains of Knowledge from which all the ideas we have, or can naturally have, do spring." "First, our Senses, conversant about particular sensible objects, do convey into the mind several distinct perceptions of things, according to those various ways in which those objects do affect them. And thus we come by those ideas we have of Yellow, White, Heat, Cold, Soft, Hard, Bitter, Sweet, and all those which we call Sensible Qualities, which when I say the senses convey into the mind, I mean they from external objects convey into the mind what produces there those Perceptions. This great source of most of the Ideas we have, depending wholly upon our senses, and derived by them to the Understanding, I call SENSATION."