Is evil an illusion?

The following was intended to be my notes - which turned into more of a musing, or perhaps a rant - that I prepared ahead of a small group meetup several years ago. This has sat in my drafts since then, but I never published it because I didn't think I had a good reason to publish it. However, this is my blog - do I need a good reason to publish anything here?

Some worldviews attempt to explain our experience of "evil" in terms of chemical reactions and electrical signals in the brain - and not just evil, but all thoughts, feelings, and actions. Every thought we think and feeling we feel is simply in the brain. This doesn't make those experiences inherently right OR wrong, they simply are (according to this line of thinking).

If you are suffering, it's only because you feel like you are suffering. The chemical reactions and electrical signals in your brain make you feel these things, but that doesn't mean that those feeling reflect moral reality. If we see egregious evil and feel strongly repulsed by it, those thoughts and feelings are only the effects of brain chemistry.

The cost of adopting this worldview is high. It's not hard to find egregious evil: Hitler, the crusades, the recent events with Gabby Petito, etc. You have to write off not only the feelings that you and everyone else instinctually have about these evils, but also the actions themselves as simply facts about reality. They are neither right nor wrong. I don't know of anyone who actually lives this way. People have passwords on their phones, locks on their doors and cars, don't display their SSNs publicly, etc, which doesn't seem consistent with the idea that evil is an illusion. What are you protecting yourself from, if not from evil?

Ultimately, this worldview runs in opposition to pretty much all history of human experience. It requires us to deny our most impactful experiences. Even if you believe that objective morality need not come from God (which seems difficult to justify, but is a separate question), these is no denying that evil just seems to exist. Some might explain it in terms of human preservation and evolution: we think murder is wrong because it harms the propagation of our species. This is not adequate though. Why do we believe animal abuse is wrong? Why do we have issues with "noble lies", especially from the government? These things don't have any real threat to the survival, or thriving, of our species. Some examples might even make surviving/thriving more likely!

Simply put: denying that evil exists does not negate its reality.