Freedom makes man a moral subject. When he acts deliberately, man is, so to speak, the father of his acts. Human acts, that is, acts that are freely chosen in consequence of a judgment of conscience, can be morally evaluated. They are either good or evil. The object, the intention, and the circumstances make up the “sources,” or constitutive elements, of the morality of human acts.
The errors of situation ethics, proportionalism, and consequentialism all relate directly to a failure to understand the text above. Utilitarianism and legalism have at least an indirect relationship to this as well.
Situational Ethics was pioneered by Joseph Fletcher. Situational Ethics, according to Fletcher’s model, states that decision-making should be based upon the circumstances of a particular situation, and not upon fixed Law. However, this is clearly rejected by the Church, because while the circumstances do affect the moral act, they are never the final determinant. As the Catechism states, “It is therefore an error to judge the morality of human acts by considering only the intention that inspires them or the circumstances (environment, social pressure, duress or emergency, etc.) which supply their context.
There are acts which, in and of themselves, independently of circumstances and intentions, are always gravely illicit by reason of their object; such as blasphemy and perjury, murder and adultery. One may not do evil so that good may result from it.”
In other words, the object, the material of the act, must be objectively good, and this can never be “mitigated” by circumstances. The subjective guilt of the person committing such an act may differ based on their understanding of this, but the objective moral act remains evil. While circumstances can change the intensity of the goodness or badness of the act, they do not determine it to be one or the other.
Consequentialism is the group of ethical theories claiming that the consequences of conduct are the basis for judgment about the rightness of that action.This theory claims that a morally right act (or omission) is one that will produce a good outcome, or consequence, or that at least a good consequence can mitigate the evil involved. Clearly this teaching is rejected in Catholic moral theory as incompatible with objective moral norms and natural law.
A similar current moral theory that has been explicitly rejected in Veritatis Splendor is called proportionalism. Its proponents often present it as [a modified consequentialism] in line with Catholic moral teaching, but it does not hold up to scrutinization. Proportionalism teaches that a physical evil can sometimes be knowingly committed while not being at the same time a moral evil. It attempts to label some actions pre-moral. “Thus, in the concrete, one must always leave open the possibility that in some given set of circumstances, what would normally be a moral evil is not truly so, this is only a ‘physical’ or ‘ontic’ evil when it brings about greater goods or is justified by a proportionate reason for doing so.” (Moral Magisterium, Lesson 6)
Proportionalism does not seem much different than situation ethics, although it takes results as its determining factor over that of circumstances. It says that an action is right or wrong, depending on the consequences it produces. The proportionalist would say that it is never right to go against an objective moral principle unless a proportionate reason would justify it. But this repeats the error of doing evil that good may come of it. Proportionalism seems to seek a different material (result) than situation ethics (circumstance) to achieve the same result: the rejection of an objective absolute in an act itself (the matter of the act) being evil.
It is hard to deny that the prime mover in recent attempts to circumvent the Church’s teaching on absolute moral objects is the reception (or rejection) of Humanae Vitae. So we will take the example of birth control; it is against natural law, because it artificially separates what God has made one: the act of spousal love and the possibility of procreation. Contrary to the question asked about “still allowing the spousal exchange of love between the partners,” it rather distorts this love. It becomes two people using each other as objects of pleasure. True love is self-sacrificial. The couple instead could, if for grave reasons, abstain to some degree such as would be the case with natural family planning, or even completely if necessary. This would show great love and conformity with God’s design for the marital act. The situation and/or the proportionate goods cannot change the objective truth of God’s willing the marital act to be open to life.
In brief, the moral object must always be good (or at least indifferent) as well as the intention. What we do, and not just the outcome we intend, is part of the moral act. “We must all appear before the judgment seat of Christ, so that each one may receive good or evil, according to what he has done in the body” (2 Cor 5:10, quoted in VS 73).
This is best summarized by saying that proportionalists claim that there can be not judgment made of an act as good or evil from the object alone, but the circumstances and intention must be considered. This is true of moral good, but not of moral evil. If an object is objectively evil, the consequences (circumstances) and intention cannot make it good.
The circumstances of an action are individual conditions of specific acts in time and place that are not of themselves part of the nature of the action. They do, however, modify the moral quality of the action. The who, what, when, and where of actions are bearing on the goodness or otherwise of specific actions. These circumstances cannot, of course, make an objectively evil action to be good, but they can increase or decrease both moral culpability and the degree of goodness or evil in the act.
Utilitarianism is a theory in that holds that the proper course of action is the one that maximizes overall “happiness”. It is really another sort of consequentialism, seeking the common good over that of individuals, most explicitly developed by J. S. Mills.
There are several major problems with utilitarianism. First of all, it views the collective as a sort of unity beyond what it is. It ignores the person as such. Also, it is difficult to define exactly what maximum “happiness” is. In reality, this usually is reduced to maximum pleasure and minimum pain, and even when this is admitted, it is rarely demonstrated how even this standard can have any true objective reference. One must arbitrarily assign a value to different pleasures and pains, which obviously include physical and emotional pleasures and pains that are at best difficult to commensurate.
Legalism, in Christian theology, is a usually-pejorative term referring to an over-emphasis on discipline of conduct, or legal ideas…and ignorance of the grace of God or emphasizing the letter of law over the spirit. Legalism is alleged against any view that obedience to law, not faith in God’s grace, is the pre-eminent principle of redemption.
It can be contrasted with the heretical doctrine of antinomianism which states that Christians are exempt from the obligations of moral law. As in most heresies, there is truth in what is affirmed against legalism, but also error in what is rejected.
We may once again look to the Catechism for the true and balanced response. The vocation to eternal life is supernatural. It depends entirely on God’s gratuitous initiative, for he alone can reveal and give himself. The preparation of man for the reception of grace is already a work of grace. God’s free initiative demands man’s free response. God grants his creatures not only their existence, but also the dignity of acting on their own, of being causes and principles for each other, and thus of co-operating in the accomplishment of his plan. “For God is at work in you, both to will and to work for his good pleasure.” “He Who created you without your cooperation, will not save you without your cooperation.”
Quotations from Scripture, the Fathers, and the Catechism could certainly be multiplied beyond this, but the Doctor of Grace will be given the final words here. Recognizing that there is an objective and absolute moral law that we must follow, yet finding ourselves in need of God’s mercy and grace to follow His commands, we ask with Augustine that God “”Give me what you command and command what you will.”
 CCC 1749
 CCC 1750
 CCC 1756
 CCC 1998
 CCC 2001
 CCC 2002
 CCC 306
 Phil 2:13
 St. Augustine, Sermon 169, 13
 St. Augustine, Confessions, 10, 29