When I was younger, I was a determinist. Some would call that a fatalist: I believed that whatever happened was what was going to happen anyway. It was all equally fate. We experienced ourselves making choices from an insider's perspective, but that didn't mean they didn't happen step by step according to causality and the laws of physics.

The reason I'm not a fatalist is that there's nothing to lose. If I'm predetermined from birth to death, then I can't help it anyway: so if I believe in free will and that somehow harms me, I could not have done otherwise; those were always the fixed rules of my game.

If I'm not predetermined completely, then in some sense I stand to lose anything I could possibly lose by getting this wrong and thinking "I have no choice." I stand to lose anything and everything choice might offer, including my life itself.

A lot depends on what we actually mean by "I," but that's a rabbit hole I don't want to get lost in right now. My organism can have a choice the same way an NPC can have a choice based on how you're playing. "Having a choice" doesn't mean "non-deterministic," necessarily. Your FitBit could "have a choice" to wake you up with an alarm that depends on your current biometrics - that is, on whether it calculates this to be a good time or not. By human standards, that isn't a choice, because it's deterministic. But from some definitions of the FitBit's "I" (if there is one), that's a choice anyway. It can't know your biometrics in advance, so it's waiting for your input, which when it arrives will inform its action. The process of that informing and that action could in theory "feel like something," even if it can only flow one way that time. The FitBit is in some sense "surprised" by your biometric data, as it didn't know it in advance: that's the definition of information, and of surprise, which are now often defined as the same thing.

I find the idea of all this experience - some really painful - very wasteful if we don't actually, in that experiencing, gain the power to co-invent the course of nature.

If I have nothing but determinism in me, what do I gain for my pain?

Learning, awareness - but I could learn from data without experiencing that. So why experience it?

I'm convinced we feel something because we are participating in the creation of the universe.

Creation, not just unfolding.