There is a whole school of thought that revolves around the idea that everything is relative and therefore nothing can be proved. The philosophy of relativism teaches that the premises people use to make judgments vary according to their genetic makeup, backgrounds, and environments.

However, an axiom is a self-evident truth that requires no proof, and rational, honest people do not require proof for self-evident truths. You do not have to prove that the sun comes up every morning, but there was a time when it was necessary to prove that the earth revolved around the sun.

As with invalid analogies, if you allow someone to get away with making the argument that a self-evident truth cannot be proven, an invalid conclusion is also a forgone conclusion.

Be alert and refuse to take the bait.