There can be a kind of moral unity.
There is no magisterial document which says anything like this claim of moral unity.
HV specifically rejects this claim that acts can merge, such that an act which is intrinsically evil when done by itself somehow becomes moral by being done with other acts. Although HV is mainly on the topic of contraception, the same basic moral principles apply to all acts.
The teaching of the Magisterium in the CCC, the Compendium, and Veritatis Splendor make it absolutely clear, as a required belief and not an opinion, that there are three fonts of morality and that all three fonts must be good in order for an act to be moral.
The claim that a set of knowing choices becomes a moral unity is essentially a denial of the doctrine of the three fonts, because each act is not evaluated by the fonts that spring up from and apply to that act. This is only used to justify sexual acts for some reason.
The teaching of the Magisterium that intrinsically evil acts are always immoral, regardless of intention or circumstances is not an opinion, but a required belief. The claim of a moral unity also has the effect of justifying intrinsically evil acts as long as they are part of that ‘moral unity.’
And the various parts (chaste foreplay) leading up to the completion of the act form a moral unity with the marital act.
There is no magisterial teaching which supports this claim, nor any magisterial document using the term ‘moral unity’.
In moral theology, an act is a knowing choice. A set of choices of various sexual acts is not one act. This approach of ‘moral unity’ has the effect of justifying any number and kind of intrinsically evil acts, merely on the basis that one act of natural intercourse occurs at some point in time. In this way, all manner of sexual sins are said to be justified, and the teaching of the Church on the three fonts and on intrinsic evil is nullified (or mostly just ignored).
Labeling an act as ‘chaste’ or as ‘foreplay’ does not justify the act. Labeling a set of acts as a ‘moral unity’ does not justify the acts.
And no one will be able to** produce even one document** (I have stated this numerous times and have not ever had one produced) from the Church that says it does…
Pope Paul VI: “The Church, nevertheless, in urging men to the observance of the precepts of the natural law, which it interprets by its constant doctrine, teaches that each and every marital act must of necessity retain its intrinsic relationship to the procreation of human life. This particular doctrine, often expounded by the magisterium of the Church, is based on the inseparable connection, established by God, which man on his own initiative may not break, between the unitive significance and the procreative significance which are both inherent to the marriage act.” (Humanae Vitae, n. 11-12).
Therefore, all non-procreative sexual acts are intrinsically evil, and are not justified by the intention to commit a subsequent act of natural intercourse, not by the circumstance that the non-procreative act occurs in conjunction with other acts.
Pope John Paul II: “Consequently, circumstances or intentions can never transform an act, intrinsically evil by virtue of its object, into an act ‘subjectively’ good or defensible as a choice.” (Veritatis Splendor, n. 81.)
Where are the magisterial documents stating ‘moral unity’ or permitting unnatural sexual acts as foreplay? There are none. But I have repeatedly quoted Saints Augusting and Aquinas as condemning unnatural sexual acts within marriage.
However, there are documents teaching that the three fonts of morality are the basis for determining if an act is moral, and that intrinsically evil acts are always immoral, and that each and every marital act must be both unitive and procreative.
It is absurd and patently contrary to the plain meaning of HV to say that ‘each and every marital act’ permits any number of non-procreative and non-unitive sexual acts, supposedly even including climax for the wife. If that were true, then the phrase ‘each and every’ would be null and void.
Neither is it valid to argue, as a justification for sexual intercourse which is inherently non-unitive or non-procreative, that such intercourse would merge with unitive and procreative marital acts of past or future to form a single moral entity, and so be qualified by exactly the same moral goodness as those procreative acts (compare Humanae Vitae, n. 14).
“But no reason, however grave, may be put forward by which anything intrinsically against nature may become conformable to nature and morally good. Since, therefore, the conjugal act is destined primarily by nature for the begetting of children, those who, in exercising it, deliberately frustrate its natural power and purpose, sin against nature and commit
a deed which is shameful and intrinsically vicious.” (Pope Pius XI, Casti Connubii, n. 54)
“No difficulty can arise that justifies the putting aside of the law of God which forbids all acts intrinsically evil. There is no possible circumstance in which husband and wife cannot, strengthened by the grace of God, fulfill faithfully their duties and preserve in wedlock their chastity unspotted.” (Pope Pius XI, Casti Connubii, n. 61)
