text: Be not disgusted, nor discouraged, nor dissatisfied, if thou dost not succeed in doing everything according to right principles; but when thou bast failed, return back again, and be content if the greater part of what thou doest is consistent with man's nature, and love this to which thou returnest; and do not return to philosophy as if she were a master, but act like those who have sore eyes and apply a bit of sponge and egg, or as another applies a plaster, or drenching with water. For thus thou wilt not fail to obey reason, and thou wilt repose in it. And remember that philosophy requires only the things which thy nature requires; but thou wouldst have something else which is not according to nature.- It may be objected, Why what is more agreeable than this which I am doing?- But is not this the very reason why pleasure deceives us? And consider if magnanimity, freedom, simplicity, equanimity, piety, are not more agreeable. For what is more agreeable than wisdom itself, when thou thinkest of the security and the happy course of all things which depend on the faculty of understanding and knowledge?