X. The next point for discussion is one which is copious enough, but rather abstruse; for it touches in some points on natural philosophy, so that I am afraid that I may be giving the man who will reply to me too much liberty and licence. For what can I think that he will do about abstruse and obscure matters, who seeks to deprive us of all light? But one might argue with great refinement the question,—with how much artificial skill, as it were, nature has made, first of all, every animal; secondly, man most especially;—how great the power of the senses is; in what manner things seen first affect us; then, how the desires, moved by these things, followed; and, lastly, in what manner we direct our senses to the perception of things. For the mind itself, which is the source of the senses, and which itself is sense, has a natural power, which it directs towards those things by which it is moved. Therefore it seizes on other things which are seen in such a manner as to use them at once; others it stores up; and from these memory arises: but all other things it arranges by similitudes, from which notions of things are engendered; which the Greeks call, at one time ἔννοιαι, and at another προλήψεις. And when to this there is added reason and the conclusion of the argument, and a multitude of countless circumstances, then the perception of all those things is manifest, and the same reason, being made perfect by these steps, arrives at wisdom. As, therefore, the mind of man is admirably calculated for the science of things and the consistency of life, it embraces knowledge most especially. And it loves that κατάληψις, (which we, as I have said, will call _comprehension_, translating the word literally,) for its own sake, (for there is nothing more sweet than the light of truth,) and also because of its use; on which account also it uses the senses, and creates arts, which are, as it were, second senses; and it strengthens philosophy itself to such a degree that it creates virtue, to which single thing all life is subordinate. Therefore, those men who affirm that nothing can be comprehended, take away by their assertion all these instruments or ornaments of life; or rather, I should say, utterly overturn the whole of life, and deprive the animal itself of mind (_animo_), so that it is difficult to speak of their rashness as the merits of the case require. Nor can I sufficiently make out what their ideas or intentions really are. For sometimes, when we address them with this argument,—that if the doctrines which we are upholding are not true, then everything must be uncertain: they reply,—Well, what is that to us? is that our fault? blame nature, who, as Democritus says, has buried truth deep in the bottom of the sea.