Full Idea
That thing is called free which exists solely by the necessity of its own nature, and of which the action is determined by itself alone.
Gist of Idea
A thing is free if it acts by necessity of its own nature, and the act is determined by itself alone
Source
Baruch de Spinoza (The Ethics [1675], I Def 7)
Book Reference
Spinoza,Benedict de: 'Ethics, Improvement of Understanding, Letters', ed/tr. Elwes,R [Dover 1955], p.46
A Reaction
This points to the obvious thought that nothing is independent enough to achieve freedom. Our concept of nature is of almost endless interdependence. God seems the only thing that could possibly qualify, though some might say humans could.