M. Comte claims no originality for this conception of human knowledge. He avows that it has been virtually acted on from the earliest period by all who have made any real contribution to science, and became distinctly present to the minds of speculative men from the time of Bacon, Descartes, and Galileo, whom he regards as collectively the founders of the Positive Philosophy. As he says, the knowledge which mankind, even in the earliest ages, chiefly pursued, being that which they most needed, was _fore_knowledge: "savoir, pour prevoir." When they sought for the cause, it was mainly in order to control the effect or if it was uncontrollable, to foreknow and adapt their conduct to it. Now, all foresight of phaenomena, and power over them, depend on knowledge of their sequences, and not upon any notion we may have formed respecting their origin or inmost nature. We foresee a fact or event by means of facts which are signs of it, because experience has shown them to be its antecedents. We bring about any fact, other than our own muscular contractions, by means of some fact which experience has shown to be followed by it. All foresight, therefore, and all intelligent action, have only been possible in proportion as men have successfully attempted to ascertain the successions of phaenomena. Neither foreknowledge, nor the knowledge which is practical power, can be acquired by any other means. The conviction, however, that knowledge of the successions and co-existences of phaenomena is the sole knowledge accessible to us, could not be arrived at in a very early stage of the progress of thought. Men have not even now left off hoping for other knowledge, nor believing that they have attained it; and that, when attained, it is, in some undefinable manner, greatly more precious than mere knowledge of sequences and co-existences. The true doctrine was not seen in its full clearness even by Bacon, though it is the result to which all his speculations tend: still less by Descartes. It was, however, correctly apprehended by Newton.[1]