Well your ethics should shift considerably. Retributive justice is morally repugnant for someone who does not believe in absolute free will.

+1. The moral basis for much of our societal rules and behaviors is unsound if free will is incompatible with biology. We in the US do so many things based on Puritan moral views that are so very harmful and counterproductive to our goals, based on an incorrect understanding of how the world works.

The existence of punishment changes the inputs to the system and, thus, changes the outputs of the system. The system in this case being the mind and it's output being behavior.

Right which is why I specifically said retributive justice. Other penal forms may still be morally justified for the sake of the “system” as it were.

But the very existence of ethics is in danger in absence of free will. Existence : as in, whom do you blame for hanging the terrorist ? The lawyers, judges, jury, witnesses did not have free well : so it was inevitable that the terrorist be hanged.

> What decisions do you make differently with your knowledge that free will is an illusion? What choices do you make differently?

Interestingly, my belief in the illusory nature of free will has had a huge impact on my life. I'm a much more laid-back person than I used to be. I don't stress out so much over making mistakes. It has also helped me in a lot of practical aspects of my life. For example, it has helped me lose weight. I think about my desire to eat as my brain playing a sort of a trick on me, and that makes it easier for me to "decide" not to give in to the craving. I treat the part of me that wants to eat the cookie as a separate entity from "me" that just happens to reside in the same brain, and I interact with it through internal dialogs like I would a small child. It sounds weird, but it works, at least for me. I'm almost down to the same weight I was in college (and I'm 54).

Erm ... it seems to me that if there was no free will then your beliefs couldn't have any actual consequences at all, they and your cookie cravings are just different aspects of the unfolding of the universe

His beliefs are also a part of the unfolding of the universe, and as such his beliefs also have consequences even if he has no control over what he actually believes.

Dockerized micro-services for the self!

It's a throwaway comment, but perhaps (as with most problems of philosophy) the problem is really semantic? What does "will" really mean, in free will? It imagines a little person sitting in my head piloting my body. It seems equally plausible that there is no central "me", I'm just a competing mess of programs running in my brain (at varying levels of abstraction), with the gut biome being the BIOS. There may be a hypervisor in there somewhere, but that's the most you can hope for in terms of rational direction. Everything runs in parallel, and the part I think of as "me" rationalizes decisions after the fact.

Horizontal gene transfer? A literal virus that changes who you are. It's interesting to think that by going paleo or vegan you can perhaps become another "person"...