Aquinas and the Principle of Double Effect

Over the course of our lives we will be faced with many difficult decisions.  These decisions may be life altering and may change us forever.  In the encyclical Veritatis Splendor, Saint Pope John Paul II writes, “Acting is morally good when the choices of freedom are in conformity with man’s true good and thus express the voluntary ordering of the person towards his ultimate end: God himself, the supreme good in whom man finds his full and perfect happiness” (Veritatis Splendor para 72).  In these circumstances there are right and wrong moral decisions, and the principles of double effect and material cooperation assist us in making the right decision.

The principle of double effect, or PDE, has its origins with St. Thomas Aquinas and is one of the best strategies in solving complex morality issues.  This principle states that it is possible to make a decision that has both good and bad effects.  Just because it has both effects does not mean that it is not morally permitted.  There are conditions that must be met for a decision to fall under this principle.  The act itself must be good or morally indifferent.  The good effect must not come from evil.  Evil is not the intended result.  If evil is the effect it should be a last resort and the good effect should be equal or greater.  This principle, along with material cooperation, help to make the best moral decision out of possibly the worst of circumstances.

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            When an individual assists in some way in wrongdoing this is called material cooperation, and there are two categories.  The first is known as immediate material cooperation an individual, though they may disapproval, assists in the act.  They may tolerate it, but do not approve.  The second in Mediate material cooperation, and consists of proximate mediate and remote mediate material cooperation.  Proximate mediate is immoral in all cases, and may consists in the manufacturing of a device, such as Sarin gas, that is only meant for evil.  Remote mediate may be permitted based on the circumstance, such as not being able to find viable employment elsewhere and having to feed your children.  In this circumstance someone may be the janitor at the factory that produces Sarin gas because employment may not be had elsewhere.  This is why moral decisions should be looked at to get all the factors.  Regarding this Pope John Paul II writes, “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 para 75).

A hard case when it comes to PDE is the subject of abortion.  Abortion is the termination of a human life while it is still in the womb.  Abortion being wrong is not a matter of just the church saying so.  This can be deduced by the use of reason without the aid of faith (Smith & Kaczor 29).  Imagine if a couple had six kids at home, and while pregnant with the seventh the mother is diagnosed with uterine cancer.  Removing the cancer would end the pregnancy, but not removing it the mother will perish while the child lives.  After much prayer and anguish the parents opt to remove the cancer for the benefit of the six children they have to raise.  This is an effective use of PDE since the intent was not to terminate the pregnancy, but to remove the cancer.  Conversely a woman who chooses to terminate the pregnancy because she just does not want another child does not meet the conditions of PDE.

Proponents of proportionalism reject PDE because the moral actions of the individual should be judged by the consequences that ensue.  In short, the outcome that brings the greatest good or the least bit of evil is the appropriate action.  Proportionalism does not have a set definition of what is morally upright, and it can change based on the individual.  It is because of these reasons that proportionalism is condemned by Veritatis Splendor.


Works Cited

Pope John Paul II.  Veritatis Splendor.  Accessed February 27, 2018.

Smith, Janet E and Kaczor, Christopher.  Life Issues, Medical Choices:  Questions and Answers For Catholics.  Servant.  Cincinatti, OH:  2016.  Print


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