My students recently submitted assignments on the problem of evil. The reading on this topic included J. L. Mackie’s famous essay “Evil and Omnipotence” (not “Evil and Impotence,” as a student wrote in an essay for a colleague of mine).
Mackie discusses the argument that good is a statement of contrast, and thus that there cannot be good without evil. Mackie is not particularly impressed with this line of argument, but students often disagree with Mackie about this.
An interesting implication of this line of argument, one that I had not thought of before, is that, if it is correct, then it would seem to be the case that God was not good until evil came into existence, unless one wishes to posit that evil is eternal.
Since few theists would accept either possibility, then stating that good by definition requires the existence of evil cannot be an effective theistic solution to the problem of evil.