One of the most common arguments that leftists (especially of the Atheist Left) use as alleged arguments against Christianity is one of definitional retreat about evil existing. They claim that if a good and powerful God existed then evil wouldn't exist, and our response is that evil is undefined if absolute good doesn't exist, and absolute good cannot exist if there is no superhuman arbiter who can properly define it. Then they go on to play the relativism card and flat-out exclaim justice to be subjective. Can anyone see the contradiction in this?
I certainly can. If justice were subjective, then it would be just one person's definition of what constitutes injustice against another's. Is murder unjust? Is robbery unjust? Is income inequality unjust? Is rape unjust? If they are unjust for one person but not for another then they aren't unjust at all. No, in order for injustice to be properly defined, justice must also be objectively defined. If justice is subjective then so is injustice subjective; if injustice is objective then so is justice objective. Thinking that you can have this both ways is extremely foolish and intellectually dishonest.
I am used to describing chain reactions using the infamous dominoes analogy. If one domino falls, they all do. The first domino in this issue of evil is the question "Is relativism true?" If it is, then the next domino is the definition of justice, then the next domino after that is the person's right to use injustice — an undefined variable at that point — as evidence to support their claim that their is no God. Finally, after they then contradict their own relativism by admitting that relativistic grounds are problematic ones from which to raise this objection, another domino — atheism itself — also falls to ruin.
This, of course, is completely aside from the fact that relativism is self-refuting to begin with — the claim that justice is subjective has an implication that it is unjust to claim otherwise behind it. If it is unjust to claim that justice is objective, then the notion that it is unjust to claim that justice is objective is itself also unjust. It falls in the very same category as suff that I have already gone over in previous blog posts — truth denial ("is that true?"), relativism generally ("is that relative?"), moral relativism ("is that true for all?"), and other such claims — the claim contradicts the very idea that it intends to advance.
So, are you a Christian or is your entire worldview destined to collapse like a stack of dominoes? If you are the former and know how to properly defend it as a belief system, then you're all good. If you're the latter — a self-refuting relativist — then you'd be a hypocrite for claiming to be reasoned and a hypocrite for claiming to be anywhere near in touch with reality. What's at stake here is… well, everything.