Thank you for your thoughtful questions, Susana. Here are my replies to them, as best as I can manage them in this moment.

1 - We can still have an undertanding that actions have consequences. Dangerous criminals should still be locked up to protect others. And other punishments could still act as a deterrent.

2 - Lack of a belief in free will is not fatalism. We can still understand the benefit of taking positive actions to improve our lives. I explain this in the section called "Fatalism vs Determinism" in the article: https://edward-john.medium.com/do-we-have-free-will-almost-certainly-not-4ef11c73ebce

The choice to not improve your life is still a choice. Complete inaction is itself an action. Try doing absolutely nothing for as long as you can. Eventually you will feel the desire to do something. But where does that feeling come from?

3 - No, if our choices are predetermined, that doesn't imply a supernatural force. Well, not a conscious one, anyway. It just means that things happen because other things caused them to happen. Yes, we can affect the chemicals in our brain, but it's still only the neurology of our brain affecting itself. A modern analogy could be that of machine learning, where a computer program is sophisticated enough to be able to modify itself without external input.

4 - Great question! Well, scientists have an understanding of which parts of the brain are active during specific mental states. But as for why or how brain activity causes us to experience these thoughts and other mental states, that seems to be unknown at the moment.