|Gozzoli's "The Glory of St. Thomas"|
On the one hand, St. Thomas does actually say what the dissenters claim he says, but on the other, he actually means the opposite of what they say he means. Here is the relevant passage from his Summa Theologiae [ST hereafter: italics mine here and below]:
. . . conscience is nothing else than the application of knowledge to some action. Now knowledge is in the reason. Therefore when the will is at variance with erring reason, it is against conscience. But every such will is evil; for it is written (Romans 14:23): "All that is not of faith"--i.e. all that is against conscience--"is sin."
Therefore the will is evil when it is at variance with erring reason. ST IiaIae
Yes, it is “evil” to disobey even an erroneous conscience, but conscience does not mean “feelings” or “opinions” (the common misrepresentation); rather, it is “the application of knowledge to some action”. To St. Thomas (and to the Church) it is the process of applying moral principles to one’s particular situation, or “knowledge applied to an individual case”, as he describes it in another section (ST I, 79, 13). Since conscience is the reasoning process by which we determine whether a course of action is good or evil, going against conscience means deliberately choosing what we believe to be evil, even if we do not actually accomplish evil:
But when erring reason proposes something as being commanded by God, then to scorn the dictate of reason is to scorn the commandment of God. ST IiaIae
When we violate our conscience, then, quite apart from the actual harm we might or might not be doing (objective sin), we are intentionally rejecting what we believe to be God’s will (subjective sin): that’s why it’s "evil" to violate our conscience. This act of defiance is a sin in itself, quite apart from the sinfulness (or not) of the particular act we are contemplating.
The story doesn’t end there, of course; St. Thomas was well aware that someone might try to use his argument to justify sin. He goes on to explain that, even though we must obey an erroneous conscience, we may be morally culpable (i.e., guilty of sin) for having an erroneous conscience. He says:
If then reason or conscience err with an error that is voluntary, either directly, or through negligence, so that one errs about what one ought to know; then such an error of reason or conscience does not excuse the will, that abides by that erring reason or conscience, from being evil. But if the error arise from ignorance of some circumstance, and without any negligence, so that it cause the act to be involuntary, then that error of reason or conscience excuses the will, that abides by that erring reason, from being evil. ST IiaIae
Recall that conscience is moral principles (what he calls “knowledge” or “Divine Law”) applied to particular circumstances. For an adult Christian “what one ought to know” are the moral principles contained in Church teaching, although it is quite possible to be mistaken or misinformed, through no fault of one’s own (invincible ignorance), about the circumstances to which one is applying the principles. Therefore, invincible ignorance excuses us from subjective guilt, but failure to form our conscience properly does not. Just to be sure his point is clear, St. Thomas illustrates with the following examples:
For instance, if erring reason tell a man that he should go to another man's wife, the will that abides by that erring reason is evil; since this error arises from ignorance of the Divine Law, which he is bound to know. But if a man's reason, errs in mistaking another for his wife, and if he wish to give her her right [i.e., sexual intercourse] when she asks for it, his will is excused from being evil: because this error arises from ignorance of a circumstance , which ignorance excuses, and causes the act to be involuntary. ST IiaIae
Notice the phrase “bound to know”: whether or not adultery is wrong is not a matter of conscience, its wrongness is an unalterable reality that we are “bound” to acknowledge.
|St. Thomas did NOT make her do it|
The champions of conscience (or perhaps more properly “conscience”) over and against Catholic moral doctrine almost without exception invoke St. Thomas (when they invoke him) to justify their rejection of the Church’s teaching on one of the currently fashionable sexual issues, such as contraception, gay marriage, extra-marital sex, etc., practices that have been explicitly and unambiguously condemned in scripture and in the teaching of the Church under the sixth commandment’s prohibition of adultery. If we look at the whole passage, however, and not just the one sentence that seems to excuse dissent, we see that St. Thomas is saying explicitly that you cannot invoke conscience against these teachings. Using adultery as his example, he demonstrates that the role of conscience is not to determine basic rules of right and wrong, but to guide our own actions according to the rules we have received from God through his Church.
It would be helpful at this point to recall that sin involves a lot more than just the will of the sinner. The Church teaches that there must be three conditions for a sin to be a mortal sin: grave matter, full knowledge, and full consent or, more prosaically, "it's bad, you know darn well it's bad, but you go ahead and do it anyway". St. Thomas is here considering only the second part of the formulation, that is, whether or not you know darn well it's bad. Even if, through no fault of your own (a significant "if", as we saw above) you don't know it's bad, and so are not guilty of choosing bad, it's still bad. And it's bad because bad consequences, for you and/or society at large, are likely to follow. That's why it's a sin, after all. Consider St. Thomas's example of the unwitting adulterer. He is not guilty of subjective sin, because he is not aware of what he is doing. The act is nevertheless an objective sin, which could lead to all manner of destructive consequences: fathering a child out of wedlock (with all the attendant problems), or receiving a disease which might in turn infect his innocent wife; the other woman might receive an infection from him, and, depending on her awareness of the situation, might feel exploited or betrayed by him. If the adultery becomes known, as is likely, it will damage the man's relationship with his wife and children; if not, he may feel the need to cover up his deed and commit the further sin of lying in order protect his family . . . And on and on.
In other words, a sin is a sin is a sin, and whatever we may think, it's still a sin. As Catholics, we have ample means of knowing the Moral Law, and therefore have no excuse for disobeying it. St. Thomas writes nothing that justifies committing acts which the Church teaches to be morally wrong.
(The above is a revised and condensed version of an earlier series of five posts titled "Thomas Aquinas Said What?")