Disagree. My thoughts are imposed on me either from my environment, the way I was raised, or by my brain chemistry.
"Freedom" is kind of like "love." Everybody believes it exists but nobody can agree what it means exactly. How do you know you're in love? "Well, I can't explain it, I just know." You can never know exactly how free you are, but you sure as hell know when you're NOT.
So I think if you didn't have freedom in a physical sense...you'd KNOW.
The only collar I have around my neck is the one that attaches to my pocketbook, LOL.