Well, everything you do is determined by what happened to make you do it.How can I freely assent to the idea that there is no free-will?
I hit you with fire, your "free-will" tells you to run from it.
There's always something that causes you to do what you do.
If the first thought is "I am" how can it get in my way?
Depends on what you mean by illusion.If thoughts are illusions how did I discover the brain?
Thoughts exist, they're basically the only thing you can't be skeptical of.