There are two hypotheses in my definition. The first is that reality is a deterministic process. The second is that this process is computationally irreducible. This means that it's impossible to fully predict the future. The only way to move towards the future is for the process of creation to run, and our free will is a part of that process, not separate from it.
So there is a single path going from the past up to the present moment, but no path beyond that. The path into the future is created moment to moment and cannot be fully predicted beforehand.
The other kind of determinism, the one Laplace proposed, means that the future can in theory be seen for someone with enough power to calculate it. Computational irreducibility pulls that possibility away and makes the future undetermined, and the only way to determine it completely is by the process of creation in the moment.
You have a strong illusion of free will, but that is all it is - an illusion.
Free will is not seen empirically - there is absolutely no evidence for it, and it is not consistent with what we know about how reality works.
My answer to both is the same.
It might be a good thing to remember that model of reality which you keep tucked inside your head somewhere is just that... a model. It is not reality, itself. That collection of knowledge must itself have a deterministic view because that's the way the human mind works. Most of it has to do with isolated concepts in a vacuum, and disregards the more chaotic existence that we experience every day.
Yes, for every effect that we know the why of, there is a known cause, and for everything that we know how to do, there is a process by which we know how to do it. If you've noticed I'm nearly talking myself into circles there, you might be close to seeing my point.
If you look at your collection of knowledge about how things work and try to deduce a deterministic view from that, all you are doing is making an identity statement about the nature of your knowledge. It says nothing about the world we actually live in, and everything about knowledge, itself.
Knowledge is deterministic in nature, in other words.
There are things that we do every day that we don't consciously know how to do, and there are things that people do every day that confound any attempt at reason. Chaos exists, and so does free will. Both are essentially two sides of the same coin. True, we don't know anything about these things, and probably never will -- because by definition they defy the very meaning of what it is to know.
-But we can experience it-
Lack of understanding doesn't make the rock hurtling at your head into an illusion, nor does it do the same for free will. Deny the existence of either and you're usually in for a bad day.