The Doctrine of Double Effect (DDE) refers to the distinction between what is intended and what is foreseen, and examines the morality of that distinction when determining negative outcomes.[1] It is perceived that many organizations and governments justify their actions with this theory when assessing the morality and veracity of their business practices and policy decisions. The doctrine of double effect has many uses in describing actions as ethical or unethical which can serve to benefit the public relations industry. In most cases the theory implies that most people and their actions are intrinsically good, because the intent of their actions is to have a positive impact.


The doctrine of double effect can be traced back to St. Thomas Aquinas and his discussion of the permissibility of self-defense. He states that killing one's assailant is justified provided one does not intend to kill him. Aquinas observed that “Nothing hinders one act from having two effects, only one of which is intended, while the other is beside the intention. … Accordingly, the act of self-defense may have two effects: one, the saving of one's life; the other, the slaying of the aggressor".[2] Aquinas notes that justification is provided by characterizing the defensive action as a means to a goal that is justified.

The doctrine of double effect implies that morality is based on the initial intent of an action. Regardless of whether a negative outcome was unforeseen or not, the theory suggests that the initial act is morally justified because the intent was to have a positive outcome. The doctrine of double effect “forbids us to produce the good by means of the bad but does not forbid us to produce good by means that also produce bad”. [3] Therefore one must be able to distinguish between a negative means and a means that also produces a negative outcome.

Many examples exist where the doctrine of double effect is used to provide justification for issues of morality in society.

  1. The terror bomber aims to bring about civilian deaths in order to weaken the resolve of the enemy: when his bombs kill civilians this is a consequence that he intends. The tactical bomber aims at military targets while foreseeing that bombing such targets will cause civilian deaths. When his bombs kill civilians this is a foreseen but unintended consequence of his actions. Even if it is equally certain that the two bombers will cause the same number of civilian deaths, terror bombing is impermissible while tactical bombing is permissible.
  2. When a doctor provides pain medication to a terminally ill patient which would relieve them of pain, however a possible negative implication of the act is that the patient’s life expectancy will decrease because of the toll the medication will have their body.
  3. A doctor who believes that abortion is wrong, could feel it permissible to perform a hysterectomy on a pregnant woman with cancer. In carrying out the hysterectomy, the doctor is aiming to save the woman's life while merely foreseeing the death of the fetus. Whereas performing an abortion, by contrast, would involve intent to kill the fetus as a means to save the mother. [4]

Criticisms of the Doctrine of Double Effect

There are many criticisms of the DDE, primarily based on the fact that the rule of law implies that people are responsible for their action,s and that initial intent is irrelevant.

John Stuart Mill, a nineteenth-century advocate of the utilitarianism, rejects that two acts with the same consequence and or final result can differ ethically. Mill believes that moral analysis should not consider initial intent, therefore rejecting the concept justifying acts according the doctrine of double effect[5] .

There is also the belief that the application of the DDE is too dependent upon controversial attributions of rights, and that in some moral examinations, the concept of human rights is not present.[6]
  1. ^

    Hull, R. (2000). Deconstructing the doctrine of double effect. Ethical Theory and Moral Practice, Vol. 3, No. 2, pp. 195-207
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  3. ^

    Bennett, J. (1982). Morality and Consequences, The Tanner Lectures on Human Values II, Utah Press, pp. 47 - 116
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  5. ^

    John Stuart Mill, Utilitarianism (London: Parker, Son and Bourn, 1863), page 26.
  6. ^

    Maple, D. (2001) Revising the Doctrine of Double Effect, Journal of Applied Philosophy, Vol. 18, No, 3 p. 261