Work is not only a pleasure or a necessity, it is also a duty; though painful and joyless, work is, nevertheless, an obligation for man; it were still an obligation for him if he could live without it. Work does not only insure security: it secures dignity. Man was created to exercise the faculties of his mind and body. He was created to act. I do not speak here of what he owes to others, but of what he owes to himself. "The happy man," says Aristotle, "is not the man asleep, but the man awake," and to be awake is to work and act. CHAPTER XIII. DUTIES RELATING TO THE INTELLECT. SUMMARY. =Duties relative to the investigation of truth.=--Of intellectual virtues: that there are such. Of the three forms of the intellect: _speculative_, _critical_, _practical_. Hence, three principal qualities: _knowledge_, _judgment_ or _good sense_, _prudence_. Of _knowledge_.--Refutation of the objections to knowledge: Nicole, Malebranche and Rousseau. General duty to cultivate one's intellect: the impossibility of determining the full range of this duty. _Good sense or judgment._--Errors committed in ordinary life: sophisms of self-love, interest, and passion.--Other sophisms founded on false appearances.--Logical rules. Of prudence or practical wisdom.--Can it be called a virtue? Particular rules. =Duties relative to telling the truth.--Lying.=--Two kinds of lies: inward and outward lying. Inward lying.--Can one lie to himself? Examples. Of the lie properly so-called.--How and why it lowers the mind. _Of silence._--To distinguish between _dissimulation_ and _discretion_. Duty of silence: in what cases? Of the oath and of perjury.--Perjury is a double lie. The different duties of man toward himself, considered as a moral being, are naturally deduced from the divers faculties of which this moral being is composed. Plato is the first, to our knowledge, who has employed this mode of deduction.[108] It is after having distinguished three parts or three faculties in the soul, that he attributes to each of them a virtue proper, "virtue being," he says, "the quality by means of which one does a thing well." It is thus that the virtue of wisdom corresponds to the faculty of the understanding; the virtue of courage to the irascible or courageous faculty, or to the heart; temperance, to that of desire or appetite. To these three virtues, Plato adds another which is but the harmony, the accord, the equilibrium between these, namely, justice. Cicero afterwards took up this deduction from another standpoint.[109]