I was planning to followup my critique of Kant with a parallel commentary on utilitarianism, but was waylaid by picking up some unread material sitting in my bookcase: an anthology of Aquinas’ thought On Law, Morality, and Politics, Hackett Press, Second Edition.  (I’ll quote from this volume, which I’ll shorten to LMP, and note the online equivalents below.) The first section deals with conscience (see ST I, Question 79, A. 12).

A. 12 discusses synderesis as “principles about practical matters, principles implanted in us by nature [which]...belong[s] to ... a characteristic disposition from nature” (LMP, p. 2).  This disposition is distinct from conscience, which he examines in Article 13. Synderesis is the natural (in Aquinas’ sense of that word, derived from Aristotle) orientation toward good action. As he says several times, “synderesis always tends to the good” (LMP, pp. 1, 2; A. 12, Obj. 2 and on the contrary).

Already, Aquinas’ analysis is puzzling. I presume synderesis to be related to the Koine Greek suneidesis, translated “conscience” in the New Testament (e.g., Acts 23:1; Acts 24:16; Romans 2:15; Romans 9:1; Romans 13:5; 1 Corinthians 8:7-12; 1 Corinthians 10:25-29; etc.). What is Aquinas’ justification for creating a technical category for some “disposition” separate from conscience? Do humans have a universal disposition toward the good?

Aquinas knows that his attempted distinction is problematic: in A. 13, I answer that... (very end), he says: “Nevertheless, because characteristic dispositions are the sources of acts, we sometimes apply the word conscience to the initial characteristic dispositions from nature, namely, synderesis.” He then gives cites Jerome, Basil, and Damascene as examples of this use of conscience, and concludes: “we customarily designate causes and effects by one another.” (LMP, p. 4)

Aquinas’ traditional sources do not support his own analysis. They equate synderesis and conscience. And indeed, so they ought. Conscience is a collection of specific moral perceptions integrated into the fabric of a person’s and community’s spiritual life. All the examples from the New Testament bear witness to the emergence of a new moral consciousness, grounded in the presence and transforming power of the risen Jesus. (Romans 2:15 does not contradict this, since the conscience of the Gentiles, in which the law written in their hearts either excuses  or accuses, is an eschatological event, in which Jesus Christ is to be fully revealed as the judge of all.) E. g., the problem in 1 Corinthians 8 and 10 is the conflict between those whose conscience allowed them to eat meat sold in the marketplace (which might have previously been dedicated to idols), and those conscience, being undeveloped, felt that such meat was “contaminated” by the idolatrous practices. Paul agreed with the former: the “idols” had been desacralized; it had been manifested that there was only one true God; Christ has “decontaminated” the meat. This new moral insight freed the believer to partake of anything provided in the marketplace or in another’s home, assuming it was received in a spirit of thanksgiving toward the true God (1 Timothy 4:13). At the same time, Christians who still feared the possible “contamination” had to be respected. Their consciences were “weak”(1 Cor. 8:7)—they didn’t fully understand the moral and spiritual consequences of the new way of life in Jesus Christ. Conscience was only recognized as such because of the revelation of God in Jesus Christ.

But Aquinas’ move here is not the only puzzling part of his interpretation of conscience. In ST I-II, Question 19, Fifth Article , Aquinas addresses the question: “Is the Will Evil if It Wills Contrary to Erroneous Reason?” Suppose I believe, based on what I think are rational grounds, that my life is no longer living, and I ought to seek out assistance in committing suicide. According to Aquinas, (On the contrary), “conscience simply applies one’s knowledge to actions,.... And knowledge belongs to the power of reason. Therefore the will that wills contrary to erroneous reason wills contrary to conscience. But every such willing is evil....” (LMP, p. 5)

In this scenario (if I understand Aquinas correctly), if I believe in my conscience that I ought to commit suicide, not to commit suicide is evil. (In the Fifth and Sixth Article, there are further specifications as to what manner of erring conscience is excusable and what is not.) However, what is most provocative in this analysis is what immediately follows in the text quoted above. I pick it up in the sentence ended by the ellipsis: “But every such willing is evil, for Rom 14:23 says ‘Everything not of faith,’ that is, everything contrary to conscience, ‘is sin. Therefore the will is evil if it wills contrary to erroneous reason.’”

Remember that for Aquinas, conscience is an “act” arising out of the “disposition,” synderesis (ST I, Q 79, A. 13). This disposition is an universal ordering of all humans to the good. According to the glossary in LMP, conscience is “the dictate of reason that one should or should not do something.”

If that is true, then how can Aquinas equate an evil “conscience” with the Pauline phrase “everything not of faith?” If a human can know the dictate of reason, “I ought not commit suicide”, through reason—apart from faith—then how can an evil conscience be the absence of faith? The dictate of conscience (according to the Aquinas) does not arise either within faith or apart from faith. It arises from practical reason, determined by synderesis, the disposition (again quoting the glossary of LMP) that all humans “should seek the good proper to their human nature....” But the absence or presence of faith does not bear on this issue. I do not see how Aquinas can properly cite the apostolic text as authority for his claim.

In other words, “conscience” in Paul (and the entire New Testament canon) is a state of moral knowledge known in and through the living (in technical terms, “existential”) reality of a specific community that enacts and expresses a new experience of life and moral reasoning. Aquinas reappropriates this concept and redefines it as a state of moral knowledge known by, and accessible to all humans, apart from that new life.

Consider further the specific text Aquinas invokes. Romans 14 is dealing with the same problem being considered in 1 Corinthians 8 and 10. There were some Christians, delighted with their new spiritual and moral freedom, who declared that all foods were permitted, all days were holy (Rom. 14:2, 5). Paul’s response is threefold: 1. everything is indeed clean (v. 14); 2. but if a Christian is conscientiously convinced that something is unclean, then it becomes unclean for him; 3. don’t violate another’s conscience through the exercise of one’s spiritual freedom.

Therefore, when Paul says ” whatever is not of faith”,  he means an action in which a person violates his own conscience as to what God-in-Christ wants him to do. But this assumes that the person is in the community of believers, the body of Christ, committed to being morally shaped by the presence of the risen Christ. Paul is not talking about non-believers, who are in any case not capable of “faith” in the present instance, who are not responsible to the community of believers.