[130] We must now consider with accuracy the fourth and remaining argument. Thus they argue: if the world were eternal then the animals also would be eternal, and much more the human race, in proportion as that is more excellent than the other animals; but, on the contrary, those who take delight in investigating the mysteries of nature consider that man has only been created in the late ages of the world; for it is likely, or I should rather say it is inevitably true, that the arts co-exist with man, so as to be exactly co-eval with him, not only because methodical proceedings are appropriate to a rational nature, but also because it is not possible to live without them;