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Natural Law Ethical Theory should be applied to all situations where a moral decision must be made. Dr. Dianne Irving, MA, PhD, addressed natural law ethics in an article entitled “Abortion: Correct Application of Natural Law Theory,” which was printed in the February 2000 edition of the Linacre Quarterly. The following is an excerpt from this article.

Some examples of what natural law ethical theory is, or is not, and why it could be considered useful in this debate, include the following:

  1. It is a philosophical ethical theory, not a theological one – although it can be and is related to theology. That is, natural law ethical theory aids us in understanding which human actions are morally right or wrong through the aid of human reason alone – without the use of Divine Revelation or the teachings of the Magisterium. It has been studied and refined over the centuries as a means of addressing what is the morally right thing for us to do when faced with genuine moral dilemmas. It is not some new, brash, untried or unscrutinized moral theory. One might agree that although natural law ethical theory is by definition not a case of imposing one’s religious or belief system on others, it still might be objected that it is a case of imposing one’s ethical system on others.In response one could point to several facts: first, natural law ethical theory can well hold its own in complicated academic and heated debates compared to other philosophical ethical theories (although I will not get into that here). Second, there is simply no such thing as a “neutral” ethics which might be “perfect” for our pluralistic society – no matter how convenient such “neutrality” might be. This includes the ethical theories of utilitarianism, relativism or communitarianism – none of which are “neutral” and all of which are normative ethical theories. Therefore we are in fact constantly “forcing” some non-neutral philosophical or social ethical theory on others in this country, whether we want to acknowledge that fact or not. Finally, as pointed out in the Declaration on Procured Abortion: “It is true that it is not the task of the law to choose between points of view or to impose one rather than another. But the life of the child takes precedence over all opinions. One cannot invoke freedom of thought to destroy this life.”1
  2. In counter-distinction to many other ethical theories, natural law ethical theory is proximately and objectively grounded in our objectively knowable human nature, i.e., on what is really good or bad for us as human beings – as individuals and as members of our human communities.2 It is not simply deduced from non-empirically derived and questionable “philosophical” premises or religious dogmas, or from variable emotions or personal opinions. For example, it is wrong to use cocaine because our human natures are such that cocaine eventually seriously harms, sometimes even destroys us – body, mind, and spirit. It can also seriously harm others close to us as well as to our human society at large. That is just the way we human beings are “made”; and we can know this fact objectively and empirically.
  3. Because the basic precepts of natural law theory are proximately grounded on an objectively knowable human nature, they are applicable to all human beings, precisely because we all possess such human natures. The possession of natures which are specifically human is precisely what we all have in common. This true regardless of time, culture, background, race, sex, religion or political affiliation.
  4. Thus, if properly understood and applied, natural law theory should be ideal for our “pluralistic” society – since all of our citizens are human beings, and hold at least that in common. What is fundamentally good or bad for human beings in general will hold for us all. Certainly secondary differences must be taken into consideration; but the primary precepts of the natural law will be the same for all of our citizens by virtue of their common humanity, and these precepts cannot be changed because our human natures, and what is objectively and fundamentally good or bad for them, cannot change. It calls, indeed, for simply minimal moral requirements to guide a human polity.

Finally, in natural law ethical theory, there are three determinants of a human action which determines its rightness or wrongness, and all three determinants must be good in order for an action to be considered good.3

  1. the act itself (what the agent wills), which is either good, evil, or neutral (indifferent) by its very nature. (A major tenet of a proportionalist interpretation of classic natural law theory, an interpretation which this author rejects, is that there are no “moral absolutes”, i.e., there are no human actions which are per se good or per se evil; there are only “neutral” or “indifferent” human actions).4 For example, the act of abortion is per se evil; the acts of administering chemotherapy or performing a hysterectomy could be inherently good, or indifferent (neutral), actions.”
  2. the motive or intention (consciously willed), which is what the agent wants to achieve by the act – i.e., the end, purpose or goal of the action; why the action is performed – e.g., in order to kill a person; or in order to evade social disgrace, better spacing of children, or cure a deadly disease.
  3. the circumstances, which are the accidental surroundings of the act, which include the consequences of the act – e.g., the act of intercourse with a willing spouse or forcibly with a stranger or one’s child; or that there are no other medical treatments available.

It is critical to understand that an action which is evil in itself (by its nature) cannot be made good or indifferent by any intentions, goals or circumstances – no matter how good or praiseworthy these are per se. On the other hand, an action which is good in itself (by its nature) can be morally ruined by any gravely bad intentions or circumstances. These three determinants of a moral act are explicitly incorporated into . . . the principle of double effect.


  1. Sacred Congregation for the Doctrine of the Faith, Declaration on Procured Abortion (1974) (Alexandria, VA: St. Paul Books & Media), P. 19 (emphasis mine).
  2. Austin Fagothey, S.J., Right and Reason (second or third editions only) (St. Louis: The C.V. Mosby Co., 1963), pp. 128-131. See also Pope John Paul II, Encyclical Letter, Veritatis Splendor (Boston, MA: St. Paul Books & Media, 1993), #72 (P. 91): “Acting is morally good when the choices of freedom are in conformity with man’s true good and thus expresses the voluntary ordering of the person towards his ultimate end [good]”; also, ibid, p. 92.
  3. Fagothey, p. 112. See also Veritatis Splendor, #74, p. 93: “but on what does the moral assessment of man’s free acts depend?…[It is] the intention of the acting subject, the circumstances – and in particular the consequences of his action [and] the object itse4lf [i.e. the kind of action, i.e., inherently right or wrong or neutral]…”
  4. Note that Pope John Paul II has clarified in Veritatis Splendor that “proportionalism,” an ethical theory proposed by dissident moral theologians, is not properly natural law or morally acceptable – in particular because it rejects the very possibility of actions which are morally good or morally bad per se, i.e., by their natures – see Veritatis Splendor #79-80, pp. 100-102: “One must reject the thesis, characteristic of teleological [consequentialist, e.g., utilitarian] and proportionalist theories, which holds that it is impossible to qualify as morally evil according to its species – its ‘object’ – the deliberate choice of certain kinds of behavior or specific acts apart from a consideration of the intention for which the choice is made or the totality of the foreseeable consequences of that act for all persons concerned…There exist acts which per se and in themselves, independent of circumstances, are always seriously wrong by reason of their object [i.e., the kind of act willed]…[E]xamples of such acts: ‘whatever is hostile to life itself, such as any kind of homicide, genocide, abortion, euthanasia and voluntary suicide; whatever violates the integrity of the human person, such as mutilation, physical and mental torture and attempts to coerce the spirit; whatever is offensive to human dignity, such as subhuman living conditions, arbitrary imprisonment, deportation, slavery, prostitution and trafficking in women and children; degrading conditions of work which treat laborers as mere instruments of profit, and not as free responsible persons; all these acts and the like are a disgrace, and so long as they infect human civilization they contaminate those who inflict them more than those who suffer injustice…’”. See also ibid, #75 (p. 94), #76 (p. 77), #77 (p. 98), #78 (p.99), #90 (p. 112), #96 (p. 119), #97 (p. 119). See also John Finnis, Moral Absolutes (Washington, DC: The Catholic University of America Press, 1991.)