Full Idea
Men are mistaken in thinking themselves free; their opinion is made up of consciousness of their own actions, and ignorance of the causes by which they are conditioned.
Gist of Idea
'Free will' is a misunderstanding arising from awareness of our actions, but ignorance of their causes
Source
Baruch de Spinoza (The Ethics [1675], II Pr 35)
Book Reference
Spinoza,Benedict de: 'Ethics, Improvement of Understanding, Letters', ed/tr. Elwes,R [Dover 1955], p.108
A Reaction
I have recently come to totally agree with this. The whole concept of free will seems to me incoherent, and Spinoza pinpoints the error. We aren't equipped to know the origins of the thoughts that arrive in our consciousnesses.