It is with much trouble that some strong minds have dared to raise their voices in this Cartesian concert, having taken good care to strengthen themselves by plenty of quotations gathered from the Old and New Testaments.[66] These were then proofs positive, and at times it was prudent to use them. The side of the animals has been successively strengthened by Buffon, and indeed by everybody. At the present day, M. Flourens refuses them _thought_ alone, “this supreme faculty which the mind of man possesses, so that it may rely upon itself, and study its own mind.[67] There is here,” says the physiologist of whom we are speaking, “a strong line of demarcation; this thought which can reason about itself,--this intellect which beholds and studies itself,--this knowledge which is acquainted with itself,--evidently forms an order of determined phenomena of a clearly defined nature, and to which no animal would know how to attain. _There_ is a purely intellectual world, if we may say so, and this world belongs only to man. In one word, animals feel, understand, think; but man is the only one among all created beings to whom the power has been given of _feeling_ that he feels, of _knowing_ that he understands, and of _thinking_ that he has the _power_ of thinking.”[68] Such is the only difference. The question is now reduced to a more limited field than it has ever been before, and infinitely less vast. The thing which would be wanting in animals is a kind of internal knowledge; not the knowledge of oneself (they know this since they _feel_) but the _scientific knowledge of oneself_, which can bring reflecting and reasoning study to bear on all the interior phenomena which may occur to each. We desire fully that this may be a distinction, but solely a secondary one, and able at most to make certain races of men differ one from the other. In fact, if we form an absolute and fundamental character of humanity out of this faculty, this power of investigation into an interior world, we ought to find it in a powerful manner among all men. It will resist every other influence, it will be permanent, since, this being destroyed, man would be no longer a man, and would be lowered by this fact to the rank whence he is said to have come.