Summa Theologiae Moralis, vol. I: De Principiis

S. Th. I-II, q. 18, a. 1 and 8 ; C. Gent. III, 129.

121. State of the question. — First there arises the question about the reason for the discrimination between good and evil, namely whether

there are given some human acts which are objectively good or bad from the intrinsic, or according to the nature of the thing, or on the contrary are only so from extrinsic determination and positive will. Around this there are several errors, which are comprehended under the common name of Moral Positivism¹.

They are reduced to a twofold class:

1. For some say that the positive determination of good and evil was made by men, either a) by civil laws (Hobbes) or by the social contract (Rousseau), or b) by education (Montaigne), or c) by public opinion and the custom of the people (St Lambert), or d) by the invention of sages and the powerful (Mandeville), or e) by the evolution of the moral sense or of the collective conscience or culture (Evolutionists, v. Hartmann, Levy-Bruhl, Durkheim).

2. Others derive the discrimination from the free will of God; so the Nominalists like Occam and Gerson, Descartes, Pufendorf, likewise the commentators on Grotius like Osiander, Gronovius, Cocceius².

Against these the Catholic doctrine holds that certain actions are by their nature good or bad, independently of any positive will.

122. Thesis. There are given some actions intrinsically good or bad, independently of any will even divine.

We admit indeed that there are many actions which are morally good because they are prescribed by some divine or human law, and similarly many bad because they are forbidden; but there are some which are commanded or forbidden as in themselves honest or dishonest.

It is proved: 1) By the argument of conscience and historical induction. Psychologically and historically it is established that there are certain actions which, according to the common conscience and the perpetual and invincible persuasion of men, have always been held as naturally in themselves honest or dishonest: thus for example to love parents, to do good to one's neighbor, to speak the truth, to keep covenants, etc.; on the contrary to pursue parents with hatred, to kill the innocent without legitimate reason, to betray friends unjustly, to break promises, to utter a falsehood harmful to one's neighbor, and other things of the same kind, are held as something base and dishonest. This persuasion indeed prevails among all nations, even barbarian ones; nor is it diminished or lost by anyone, except as the moral sense is diminished or destroyed. But a persuasion so constant and universal, deeply rooted in minds so diverse and dissenting in nearly all other things, does not arise from civil law or custom, which is different among various nations, and moreover laws and customs are themselves called good and bad, for which reason they are not the primary criterion; — nor from education, the social contract, or public opinion, which likewise are not the same among different peoples; but it is derived from nature itself.

Neither can it be said that the morality of these acts depends on a free institution by God: for this institution is not known to many peoples who do not have revelation, and therefore does not explain the universality of the fact. Moreover, certain actions appear in themselves and essentially so honest or dishonest that not even a divine positive will could change their morality (e.g. God cannot make blasphemy a praiseworthy act, nor make piety a sin) : the essence of things therefore does not depend on the free will of God, nor therefore the essential relations between them. Whence S. Thomas, Q. D. de Ver. 23, a. 6 : "The will does not have the character of a first rule... ; for it is directed by reason and intellect, not only in us, but also in God... ; to say that justice depends on simple will is to say that the divine will does not proceed according to the order of wisdom, which is blasphemy".

2. From philosophical reason: The good of an entity is that which suits its nature, evil that which does not suit. And there are several actions which in themselves and naturally suit or do not suit rational human nature. Therefore there are several actions which from their very nature in themselves and naturally are good or bad.

The minor premise is proved from S. Thomas, III c. Gent. 129: « Of whatever there is a determined nature, there must needs be determined operations which suit that nature (or on the contrary do not suit it): for the proper operation of anything follows its own nature. Now it is evident that the nature of men is determined. Therefore there must needs be some operations in themselves fitting to man » (or on the contrary unfitting).

The conclusion is inductively proved from three principal matters about which human action is concerned, i. e., about a) social relations with others, insofar as man is a social being; — b) the use of external things and the governance of the body and lower powers, insofar as he is a rational being; — c) relations with God as ultimate end, insofar as man is a created being. And in these three matters actions are by their nature fitting or unfitting:

a) about social relations with other men: « Whatever something is natural, that without which it cannot be had must needs be natural: for nature does not fail in what is necessary. Now it is natural to man that he be a social animal; which is shown from this, that one man alone is not sufficient for providing all that is necessary for human life. Therefore those things without which human society cannot be preserved are naturally fitting to man: such things are that each one preserve what is his, and abstain from injuries. Therefore there are some human acts naturally right ».

b) about the use of external things and the governance of the body and lower powers: « Man naturally has this, that he use inferior things for his life's necessity. Now there is a determined measure (naturally) according to which the use of the aforesaid things is fitting for human life, which measure, if it is passed over, becomes harmful to man, as appears in the immoderate taking of foods. Therefore there are some acts naturally unfitting to man.

Likewise according to the natural order the body of man is for the sake of the soul and the lower powers of the soul for the sake of reason; just as in other things matter is for the sake of form and instruments for the sake of the principal agent. From the fact, however, that something is ordered to another, it ought to receive help from it, not indeed an impediment. Therefore it is naturally right that man so provide for the body and the lower powers of the soul that from this the act of reason and its good is not hindered, but rather helped. If however the contrary happens, it will be naturally a sin. Drunkenness therefore and revelling and the disordered use of venereal pleasures, by which the act of reason is hindered and the soul subjected to passions which do not allow the free judgment of reason, are naturally evil ».

c) about relations with God: « To each one those things naturally suit by which he tends toward his natural end; those however which are to the contrary are naturally unsuited to him... Man is naturally ordered to God as to an end. Therefore those things by which man is led to the knowledge and love of God are naturally right; whatever indeed is to the contrary is naturally evil to man ».

« Therefore it is evident, as S. Thomas concludes, that good and evil in human acts are not only according to the position of law, but also according to the natural order ».

3. From the consequences of the adverse opinion: If there is no essential and objective discrimination between good and evil, a wide road is opened to moral scepticism. For a) what today is held as bad, tomorrow, with changed legislation, or tradition or education, can be held as lawful; and therefore the true notion of moral obligation perishes: for this is conceived as something permanent and universal, not hypothetically but categorically prescribing certain actions, whereas civil laws and traditions of peoples are something unstable and particular, and can only create a hypothetical obligation. With this discrimination removed, therefore, the moral order itself collapses; — b) there have existed some most wicked customs, the attack on which by heroic and saintly persons is generally praised as progress. Yet according to positivism all customs are good; nor is there an ideal and permanent rule by which to measure progress; — c) the adversaries must assume as foundation the principle: To a God who commands (or to men who command) obedience is good and resistance is evil. Therefore something is to be admitted as good or bad before the positive precept of God (or of men). And if nothing is admitted, the foundation of the whole moral order collapses.

123. They object, the positivists and evolutionists, certain examples of polygamy, of human sacrifices, of the killing of parents out of piety, namely to avoid the burdens of old age or captivity, which are sometimes reputed honest and just; whence they conclude that the public conscience is not offended by wrongdoing, because

R. The error exists not with respect to all intrinsically honest and dishonest things, but with respect to some: for nature can fail not in all things but in some, and so some have a depraved reason from passion, or from bad custom, or from a bad disposition of nature, and they could have erred with respect to some, as in the case of polygamy, or human sacrifice, or brigandage which among some was not held unjust, or the killing of parents done to remove misery. But they erred rather about the manner of practising piety than about the very obligation of loving parents; as about the manner of worshipping God, of keeping justice, or of ordering matrimony, not about the principles themselves, that it is good to love God, to live justly, and to protect the education of the human race through matrimony. Whence already S. Thomas, in Eth., b. 3: « Some things (not all), which by some are held just and honest, by others unjust and dishonest according to the difference of times and places and persons. For something is held vicious at one time or in one region which at another time or in another region is not held vicious. And from this difference it comes about that some think that nothing is naturally just or honest, but only according to the position of law ».