Consequentialism is an ethical doctrine which holds the belief that the morality, that is, the rightness or wrongness, of a human act depends on its consequence. The most famous type of consequentialism is utilitarianism. As is well known, in utilitarianism, the basis of the morality of human acts are the consequent benefits that the act brings to many people concerned. In fact, for the utilitarian, an act is morally right if it produces greatest happiness to the greatest number of people, and morally wrong if it produces more pain than happiness to the greatest number of people concerned.
Because in consequentialism the morality of a human act is judged based on its consequence, this type of ethics, therefore, is non-prescriptive. Hence, if a deontologist says “We should not lie because it is always morally wrong to lie”, a consequentialist says “It is morally right to lie if doing so would produce a good outcome or consequence”. One good example would be a physician lying outrightly to a patient with stage 4 lung cancer who is also having a cardiac condition. Obviously, for the consequentialist, if the physician would outrightly tell the patient with a cardiac condition about her real medical condition, then it may hasten the death of the patient.
Other famous types of consequentialism are ethical egoism and ethical altruism. On the one hand, ethical egoism puts more emphasis on the idea that one ought to act in such a way that it maximizes or serves one’s self-interest. On the other hand, ethical altruism mandates that we ought to take actions that have maximum benefits for everyone except for oneself.
As we can see, consequentialism is one of the types of ethical doctrine that supports the idea that it is the end that justifies the means. As a matter of fact, consequentialism permits that the end justifies the means even if the means used is problematic.