Descartes was a learned Christian, who pondered for some time over the questions whether the human mind could be certain of anything without being supernaturally enlightened; he resolved to prove it; and to this end he imagined that he, Descartes, was certain of nothing--doubted of all--even mathematical conclusions; he then reflected on this position, and after a time the idea occurred to him that as he was capable of reflection it proved without a doubt that he, Descartes, existed, and that consequently it was no longer possible to have doubts of his own identity. The portrait of this philosopher as depicted on the cover of his works, represents him reclining in a chair thinking--thinking--thinking--and exclaiming, “Cogito ergo sum.” Those persons amongst us who are not specially interested in any system of philosophy are certainly in the majority; all know that such systems exist, and that they are noted, but from the want of reflection, however little, some persons look upon them as having sprung fully equipped, and in their present form, from the brains of their founders. But it would be incorrect, simply on the evidence of a frontispiece, to consider these philosophical processes as thus instantaneous. The systems of philosophy, even those of small value, require much time for their elaboration, and ripen slowly, and are never free from opposition. They establish close links between the living thinkers of to-day, and those who are no longer on earth. The philosophers of the Middle Ages consulted those of antiquity, the thinkers of to-day strove to be in agreement with those alike of the Middle Ages and of antiquity, and there arise from this intercommunion of knowledge, groups of ideas of which some are borrowed and some original, some true and some false; these are dependent on the intellectual lucidity and vigour of the latest arrivals in the arena. Many problems are thus threshed out before our eyes. Not long ago three philosophers were in dispute and Noiré records the arguments; the discussion turned on the question of priority of thought or speech. They agreed on the fundamental point, all three said there could be no reason without language, nor language without reason. But as they penetrated more deeply into the question, they perceived divergencies; although the conception and the word be inseparable, yet there may be a moment of time--infinitely little, doubtless--between the arrival of the one and of the other, as with twins. According to Schopenhauer conceptions were the first in the field, and their immediate duty consisted in creating words; since the mind could not deal with ideas at will, could neither evoke them, grasp them, nor reject them, whilst no signs were attached to them.