Before epilepsy was understood to be a neurological condition, people believed it was caused by the moon, or by phlegm in the brain. They condemned seizures as evidence of witchcraft or demonic possession, and killed or castrated sufferers to prevent them from passing tainted blood to a new generation.
You can do what you want, but you can’t want what you want. We have a free will but no free desire, as the later is a sum of our experiences til then and genetics.
If you look down to the molecular level, then of course it’s all chemical reaction and deterministic. The same way you could argue an artificial neuronal network is alive. Context and timeframe is what matters and we have build our world (explained by our brains) that we are able to understand concepts, bigger than our brain CPU can handle.
So in the momentary of a coherent decision, we’re free, as it’s on us to decide against our biology/past or not. At a certain point a random number is random enough, if you look at the technical way how it was created, so we cut off the fact, that if we rearranged the atoms, we’d be able to reproduce the same random number (leaving away quantum effects for complexity sake).
Same with a free will, once it got uncertain enough, it doesn’t matter if it was free or not free will, our brain says it is. We leave no room for philosophy, if we go the nihilistic way of short cuts. “There’s no free will, you’re just a rock in space.”
My 2 cents. Cheers!