Auguste Rodin
The problem of evil is an argument presented against the claims of Christianity, namely that God exists and that God is good. In condensed form it goes like this: How can a good god exist if there is evil or else he must be an evil god? We might easily ask the inverse. How can an evil god exist if there is good or else he must be a good god? Therefore if neither goodness nor evil negate God, then God can either exist or not exist and so evil has no baring on the existence of God; however goodness does have a baring on the existence of God, as I will demonstrate in this post.
Opponents of Christianity claim that evil is the evidence of an evil god: Christianity proclaims that good is the evidence of a good God. Two gods cannot exist because then neither would be all powerful. Therefore it is not possible for both statements to be true simultaneously. Neither can both be true at different times. For if either god were the true god only for a time until the other usurped him, then the first god had not all power to keep his reign and the second had not all power from the beginning. So these two statements are mutually exclusive and mutually contradictory. Only one can be true.
Does evil prove that God does not exist? To answer this we need to define what we mean by evil and God, and we need to acknowledge that goodness exists.
Evil is the deprivation of good.
God is goodness itself.
If you accept these definitions and the truth of the existence of good, then we can continue. Most people would not argue that evil is the antithesis of good but some might argue that God is goodness itself, claiming that good is a moral positive independent of a moral author. But Christianity claims that God is the author of all that is good.
Both sides recognize morality and an obligation to it, so let’s look at that common ground. Pure logic dictates that any obligation to morality is necessarily personal, because no one can be said to have a moral obligation to something as inanimate as a rock (being void of any sacramental presence of grace). From there we invoke the philosopher’s Principal of Sufficient Reason that goodness (or anything) must have an explanation; infinite contingent authors or causes are contrary to this principal. Therefore there must be one person to whom all moral obligation is owed. That person Christianity calls God, but if the opposition insists, then we can simply call him/her the original author of all goodness.
Yet it might seem that it is one thing to say that there is one original author of goodness, and quite another thing to say that goodness is the author or that goodness has its being in that author’s being. Yet since God is the supreme of all things, having nothing above him, it must be that he is the greatest good or that the greatest good is in him, such that we can say God is all good.
Now, having our definitions set, we can work with the question: Does evil prove that God does not exist? Our definitions are equivalents, so we can replace the word evil in the question with the phrase “deprivation of good”. And we can replace the word God with “goodness itself”, like so:
Does the deprivation of good prove that goodness itself does not exist?
Before we get to far away from the point, it is good to affirm what the opponents of Christianity intend this question to mean. What the opposition is getting at is that because starvation, homelessness and war are factually persistent in our world, there is no good in them or elsewhere. Just because goodness is not discernible in a given situation, it does not mean that goodness does not exist in another situation; for instance feeding the hungry, sheltering the homeless and consoling those who mourn. So definitively, no, the fact of evil cannot prove that God does not exist because the absence of goodness can’t prove that goodness and the author of goodness do not exist. In fact the absence of goodness presumes that goodness does exist; and if goodness then ultimately its perfection, which is God.
Let us attend to the objection that the question is self referencing and presumes that there must be good in order that good can be absent, therefore it is an unfair prerequisite to presume that good exists. That anyone could or would honestly make this claim would mean that such a person has never experienced or witnessed good to any degree. Despite the fact that such a claim is ridiculous, all that is needed to refute this argument without self referencing logic, is to point out some good. If good is experienced or witnessed then the experience or witness proves that good exists. That’s the definition of truth: when a thing is in accordance with reality. So if we want to win the argument the best course of action is to do good to the one posing the argument. And isn’t that precisely what Jesus taught; that we should love our enemies?
What about the inverse; Does goodness prove that God does exist? We need a definition for goodness. Let us define goodness as the presence of good (such that evil is the antithesis of goodness). If you accept this definition we can move on. We can make the same substitutions resulting in this question:
Does the presence of good prove that goodness itself does exist?
And the answer is obvious; it’s the same as two paragraphs above. If we can perceive even one single act of goodness, then it is self proving. Yes, goodness proves that God exists. Again, we don’t need logic to prove this one, empirical evidence is sufficient and it is completely within our power of free will to bring that evidence into our lives. All we need to do is some act of charity. We can also just say “Praise God!” or “Thanks be to God!” For it is good always and everywhere to give God thanks and praise.