"But if the agent could not do otherwise, then how is that free? As opposed to my view that the future is predetermined, but too complex to predict with any reliability, so it's a surprise."

What IS free, then? Nothing, right? Why insist on a category as a useful distinction when there is nothing in it?

We agree on the future being predetermined with the exception of probabilistic quantum processes - if those don't turn out to be predetermined as well. We're only 'arguing' about semantics.


"Whether illegal or prescription, therapeutic or recreational, how do mind-altering substances fit into your 'free will' theory?"

Nothing so grandiose as a theory. But you can't give consent for sex or contracts while under enough influence of mind-altering substances, so I would include being under the influence as something that would prevent a choice being considered a freely willed one.