652. Direct certitude is not necessary for the judgment of conscience, for often, as in the cases just mentioned, it is not possible. Moreover, indirect certitude suffices to give one who is in doubt such practical assurance that one’s fears become unimportant and one is able to act prudently in spite of them. (a) The principle of authority--that “in doubt we can safely follow the advice of those who are experts and truthful”--is reliable, as both the conditions required for authority (viz., knowledge and truthfulness) and also daily experience show. (b) Reflex principles likewise, although they do not prove what is deduced from them, are well founded, and point so clearly the side to be taken when judgment is suspended between alternatives that they enable one to act with all the certitude that prudence demands. Example: The principle that “in doubt decision should be given in favor of the accused,” is based on the fact that a man’s right to his life and liberty is so certain that he does not forfeit that right unless it is proved convincingly that he is guilty. 653. Examples of uncertain and certain consciences are the following: (a) Uncertain conscience: It is lawful to make a just contract (major premise certain); but this contract is just (minor premise a matter of doubt or opinion); therefore, this contract is lawful (conclusion a matter of doubt or opinion). (b) Conscience directly certain: It is lawful to make a just contract (certain); but this contract is just (certain); therefore, I may make this contract (certain). (c) Conscience indirectly certain: It is lawful to follow competent advice or a moral system approved by the Church (certain); but a competent spiritual adviser or an approved system of Moral Theology holds that this kind of contract is lawful (certain); therefore, it is lawful for me to make this contract (certain). 654. An Uncertain Conscience.--Uncertainty of conscience can be understood in two senses. (a) Conscience is uncertain in a more strict sense, if the verdict of the moral judgment on a question of lawfulness or unlawfulness is that no decision can be given either way, either because there are no reasons of importance on either side (negative doubt), or because the opposing reasons balance so perfectly that it is impossible to choose between them (positive doubt). Examples: Titus, wishing to do some drawing on Sundays, asks himself whether drawing is servile work. Not knowing the definition of “servile,” he can only reply to his doubt that he has no reasons either for affirmation or for negation. Caius reads moral authors on the same question, and the pros and cons seem to him so equally strong that he cannot pronounce for either side.