Must There be Evil if there is Good?

Christians sometimes offer a defense for the problem of evil by claiming that "there must be evil if there is good. " In other words, you can't have one without the other.

John Leslie Mackie (1917-1981), an Australian philosopher, taught at Oxford University from 1967 till his death in 1981. In 1955, he wrote an important article on the  Problem of Evil entitled: "Evil and Omnipotence" (Mind, vol. 64, no. 254, 200-212). In his essay, he offered three responses to this particular claim.

1. Good and evil are not logical opposites.

[U]nless evil is merely the privation of good, they are not logical opposites, and some further argument would be needed to show that they are counterparts in the same way as genuine logical opposites ("Evil and Omnipotence," 204-05).

2. It is not necessary that a particular quality always have a real opposite.

There is still doubt of the correctness of the metaphysical principle that a quality must have a real opposite: I suggest that it is not really impossible that everything should be, say, red, that the truth is merely that if everything were red we should not notice redness, and so we should have no word 'red'; we observe and give names,to qualities only if they have real opposites. If so, the principle that a term must have an opposite would belong only to our language or to our thought,and would not be an ontological principle, and, correspondingly, the rule that good cannot exist without evil would not state a logical necessity of a sort that God would just have to put up with. God might have made everything good, though we should not have noticed it if he had (Ibid., 205).

3. It would require only a miniscule amount of evil to provide the opposite.

But, finally, even if we concede that this is an ontological principle, it will provide a solution for the problem of evil only if one is prepared to say, "Evil exists, but only just enough evil to serve as the counterpart of good." I doubt whether any theist will accept this. After all, the ontological requirement that non-redness should occur would be satisfied even if all the universe, except for a minute speck, were red, and, if there were a corresponding requirement for evil as a counterpart to good, a minute dose of evil would presumably do. But theists are not usually willing to say, in all contexts, that all the evil that occurs is a minute and necessary dose (Ibid., 205).