Moral theology is a beautiful thing to reflect on when one is reflecting on our happiness and the virtues by which we are ordered to it. But, alas, it is also necessary for moral theology to reflect on the ugliness of sin. This should not take an inordinately important place in moral reflections, but a certain amount is necessary, and actually helpful. I have been getting a number of Curious Cat questions recently on the sin known in moral theology under the fittingly ugly name of ‘morose delectation’. The most recent question dealt more generally with the problem of consent in internal sins:
What is a directly elicited act of the will (a term you’ve used in answering several other questions)? Perhaps relatedly, can you provide any principles for discerning whether one has fully consented to an act which is objectively grave matter? I know that anxiety, sleepiness, and distraction can sometimes vitiate consent but I don’t know how to tell whether one of these or some other factor is present to a sufficient extent in specific cases (in terms of deciding whether I can receive/need to go to Confession).
My response was too long for the Curious Cat format, so I paste it here. The subject is distasteful, but since it is a problem that is often brought up in confession, I hope that the response will none the less be helpful.
“Consent” has various meanings. The relevant meaning here is of an act of the will itself, by which the will accepts a good proposed to it. This is an “elicited” act of the will— an act that proceeds from the will directly (rather than a “commanded” act, which would be the act of another power moved by the will). The will is a rational desire. That is, it is an inclination to the good that follows an apprehension of the good in the reason. Just as in the sensitive part of the soul there is a sense-desire that follows the sensation of a sensible good, so in the spiritual part of the soul there is a power that desires what is conceived of as good by reason. For reason to conceive of something as good is for it to conceive of it as fitting to the subject— that is, as tending to the subject’s happiness. Now, in a complete human act there is certain back and forth between various powers of the soul: at least between reason and will, and often between the sense powers, reason, and will. The act is one act, but one can distinguish various partial acts in it.
Let’s just look at the example from the other questions you mentioned: the example of sexual pleasure in thoughts. Imagine a young man man, let’s call him Eustace. A sexually desirable image comes up in Eustace’s imagination. He didn’t directly seek it, but it came unbidden because of some connection to something he saw or read about, or to something else he was thinking about. This image in the sense power of the imagination causes a movement in the concupiscible appetite, a sense appetite that reaches out toward the pleasurable. Now there is a pro-passion in the sensitive part of the soul. Reason becomes aware of this pro-passion. Reason can conceive of the pleasure toward which the pro-passion is inclining as unfitting. If Eustace has the virtue of chastity, this is what will in fact happen. His mind will immediately conceive of it as unfitting and dismiss it. If it does so, he has committed no sin at all: neither venial nor mortal. But, the propassion disposes Eustace to see the imagined good as fitting; that is, as tending toward happiness; that is, as good for Eustace. This is in fact one of the purposes of the passions: to dispose us to see certain things as fitting to ourselves. If Eustace is lacking in virtue he will then conceive of the sexual pleasure that can arise from the image in the imagination as good. This will then cause a certain indeliberate conformity of his will with that good, which is usually called “complacence” or “simple volition”. This indeliberate movement in his will is not a complete act of the will, it is so to speak only an element of a complete act of the will. It is not yet “consent” in the relevant sense. If the action is broken off here, Eustace has only committed a venial sin. But this indeliberate movement of the will moves reason to make a practical judgement concerning the end. This is a judgement about whether the end should be efficaciously sought now. If it were a question of an external action a lot of deliberation would be involved in this judgement, but in the case of an internal action like the one we are considering this can take place almost imperceptibly. If the practical judgement is made that the end should be effectively sought this leads to intention in the will. Intention is the efficacious desire of attaining the end by the means. At this point, in the case we are considering, all is lost, because Eustace can now immediately realize this intention. His mind will immediately take counsel about the means— which in this case are immediately evident, namely continuing to dwell on the image in his imagination. And the then his will consents to the means, commanding his imagination to keep dwelling on the image, and delights in the sexual pleasure thus attained.
In the most proper use of the term, “consent” refers only to the partial act of the will by which the means are accepted. But the relevant sense of “consent” here refers to the whole process by which the will, in interaction with reason and the sense powers, comes to accept the good of sexual pleasure as its good here and now. This is the sin which in moral theology is known as “morose delectation,” and it is a mortal sin. The process takes a long time to describe, but it does not necessarily take much time in reality. Nevertheless, the amount of time it takes can be a help to distinguishing whether there was real consent— a real, complete act of the will— or whether there was just an indeliberate volition (venial sin), or only a movement of the sensible appetite (no sin at all). In fact, Dominicus Prümmer, O.P., says that if such thoughts only last for a short time, and never lead to external actions, then one can usually assume that there was not complete consent.
Incidentally, this is probably what the priests mentioned in the other questions meant by saying that brief consent was not grave matter. Technically they are wrong; any complete consent to sexual pleasure outside of matrimony is grave matter, no matter how brief. But they were pointing at a truth: if the thought was very brief there was probably not a complete act of consent. I should have mentioned this in my first answer.
It is not always easy to determine what internal acts one has in fact elicited. And it is often counter-productive to try to ferret it out by too much introspection— especially in matters touching sensual pleasure, since then the reflection itself can be an occasion of new temptations. It is enough to mention in the confessional that such thoughts came, and one is unsure whether one consented or not. As to whether one should receive communion when in such doubt, one should follow the advice of a spiritual director who knows one’s peculiar dispositions and dominant faults.