From Pope St. John Paul II’s encyclical Veritatis Splendor (1993):
But as part of the effort to work out such a rational morality (for this reason it is sometimes called an “autonomous morality”) there exist false solutions, linked in particular to an inadequate understanding of the object of moral action. Some authors do not take into sufficient consideration the fact that the will is involved in the concrete choices which it makes: these choices are a condition of its moral goodness and its being ordered to the ultimate end of the person. Others are inspired by a notion of freedom which prescinds from the actual conditions of its exercise, from its objective reference to the truth about the good, and from its determination through choices of concrete kinds of behaviour. According to these theories, free will would neither be morally subjected to specific obligations nor shaped by its choices, while nonetheless still remaining responsible for its own acts and for their consequences. This “teleologism”, as a method for discovering the moral norm, can thus be called — according to terminology and approaches imported from different currents of thought — “consequentialism” or “proportionalism”. The former claims to draw the criteria of the rightness of a given way of acting solely from a calculation of foreseeable consequences deriving from a given choice. The latter, by weighing the various values and goods being sought, focuses rather on the proportion acknowledged between the good and bad effects of that choice, with a view to the “greater good” or “lesser evil” actually possible in a particular situation.
The teleological ethical theories (proportionalism, consequentialism), while acknowledging that moral values are indicated by reason and by Revelation, maintain that it is never possible to formulate an absolute prohibition of particular kinds of behaviour which would be in conflict, in every circumstance and in every culture, with those values. The acting subject would indeed be responsible for attaining the values pursued, but in two ways: the values or goods involved in a human act would be, from one viewpoint, of the moral order (in relation to properly moral values, such as love of God and neighbour, justice, etc.) and, from another viewpoint, of the pre-moral order, which some term non-moral, physical or ontic (in relation to the advantages and disadvantages accruing both to the agent and to all other persons possibly involved, such as, for example, health or its endangerment, physical integrity, life, death, loss of material goods, etc.). In a world where goodness is always mixed with evil, and every good effect linked to other evil effects, the morality of an act would be judged in two different ways: its moral “goodness” would be judged on the basis of the subject’s intention in reference to moral goods, and its “rightness” on the basis of a consideration of its foreseeable effects or consequences and of their proportion. Consequently, concrete kinds of behaviour could be described as “right” or “wrong”, without it being thereby possible to judge as morally “good” or “bad” the will of the person choosing them. In this way, an act which, by contradicting a universal negative norm, directly violates goods considered as “pre-moral” could be qualified as morally acceptable if the intention of the subject is focused, in accordance with a “responsible” assessment of the goods involved in the concrete action, on the moral value judged to be decisive in the situation.
The evaluation of the consequences of the action, based on the proportion between the act and its effects and between the effects themselves, would regard only the pre-moral order. The moral specificity of acts, that is their goodness or evil, would be determined exclusively by the faithfulness of the person to the highest values of charity and prudence, without this faithfulness necessarily being incompatible with choices contrary to certain particular moral precepts. Even when grave matter is concerned, these precepts should be considered as operative norms which are always relative and open to exceptions.
In this view, deliberate consent to certain kinds of behaviour declared illicit by traditional moral theology would not imply an objective moral evil.
— Veritatis Splendor 75