Proof.--Everyone judges what is good according to his disposition (III. xxxix. note); wherefore an ignorant man, who has conferred a benefit on another, puts his own estimate upon it, and, if it appears to be estimated less highly by the receiver, will feel pain (III. xlii.). But the free man only desires to join other men to him in friendship (IV. xxxvii.), not repaying their benefits with others reckoned as of like value, but guiding himself and others by the free decision of reason, and doing only such things as he knows to be of primary importance. Therefore the free man, lest he should become hateful to the ignorant, or follow their desires rather than reason, will endeavour, as far as he can, to avoid receiving their favours. Note.--I say, as far as he can. For though men be ignorant, yet are they men, and in cases of necessity could afford us human aid, the most excellent of all things: therefore it is often necessary to accept favours from them, and consequently to repay such favours in kind; we must, therefore, exercise caution in declining favours, lest we should have the appearance of despising those who bestow them, or of being, from avaricious motives, unwilling to requite them, and so give ground for offence by the very fact of striving to avoid it. Thus, in declining favours, we must look to the requirements of utility and courtesy. PROP. LXXI. Only free men are thoroughly grateful one to another. Proof.--Only free men are thoroughly useful one to another, and associated among themselves by the closest necessity of friendship (IV. xxxv., and Coroll. i.), only such men endeavour, with mutual zeal of love, to confer benefits on each other (IV. xxxvii.), and, therefore, only they are thoroughly grateful one to another. Q.E.D. Note.--The goodwill, which men who are led by blind desire have for one another, is generally a bargaining or enticement, rather than pure goodwill. Moreover, ingratitude is not an emotion. Yet it is base, inasmuch as it generally shows, that a man is affected by excessive hatred, anger, pride, avarice, &c. He who, by reason of his folly, knows not how to return benefits, is not ungrateful, much less he who is not gained over by the gifts of a courtesan to serve her lust, or by a thief to conceal his thefts, or by any similar persons. Contrariwise, such an one shows a constant mind, inasmuch as he cannot by any gifts be corrupted, to his own or the general hurt. PROP. LXXII. The free man never acts fraudulently, but always in good faith.