Necessary evil

A necessary evil is an unfavorable thing (an evil) that someone believes must be done or accepted because it is necessary to achieve a better outcome—especially because possible alternative courses of action or inaction would be worse. It is the "lesser evil" in the Lesser of two evils (or lesser evil) principle, which provides that when given two bad choices, the one that is not as bad as the other is better than the one that is the greater threat.

The Oxford Dictionary of Word Origins asserts that "[t]he idea of a necessary evil goes back to Greek," describing the first necessary evil as marriage, and further stating that, "The first example in English, from 1547, refers to a woman."Thomas Fuller, in his 1642 work, The Holy State and the Profane State, made another of the earliest recorded uses of the phrase when he described the court jester as something that "...some count a necessary evil in a Court." In Common Sense, Thomas Paine described government as at best a "necessary evil."

The use of the term "evil" in the phrase does not necessarily indicate that the thing being characterized as a "necessary evil" is something that is generally considered an "evil" in the sense of being immoral or the enemy of the good. In Fuller's use of the phrase, for example, there is no implication that court jesters are evil people, or having one serves an evil end. The term is most typically used to identify something that is merely an inconvenience or annoyance. Where an author suggests that, "[P]aperwork is a necessary evil, despised but handled with the understanding that a mistake – even a trivial one – could be costly." it is understood that the author is not deeming "" to be wicked, immoral, or evil in senses comparable to those.

Some thinkers specifically reject the idea of anything that is actually "evil" being necessary. This may manifest as an admonition for moral people to avoid participating in the activities that are perceived as evil:

The concept of "necessary evil" is an idea that must be thoroughly rejected. Evil is not necessary, and to accept it as such is to perpetuate it. Evil must be opposed, rejected, and avoided at all costs. It should never be viewed as something that we must unavoidably and inevitably participate in. We trivialize evil when we refer to it as "necessary."

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Wikipedia