system
Given the following post, respond as if you're commenting on Reddit:
human
What effect would a violation in CPT symmetry have on our current understanding of physics?

I only have a "practical" understanding of quantum physics from taking physical chemistry, and so the "finer points" of modern particle physics are lost on me. I recently read about how there are no individual symmetries for charge, parity, or time and instead there appears to be a single symmetry of all of these together. This lead me to wonder what the implications of this theory being incorrect would be.
gpt
You can derive CPT symmetry from Lorentz invariance (the laws of physics are the same in every reference frame + there is a speed limit) and quantum field theory, which is based on Lorentz invariance.

A violation of CPT would mean quantum field theory cannot be right. We know it is at least an excellent approximation, but CPT violation would mean either the universe is not Lorentz invariant (there is a preferred reference frame, or something else weird is going on) or the whole idea of quantum field theory is a dead end. The latter looks very unlikely given its success so far.