Only that thing is free which exists by the necessities of its own nature, and is determined in its actions by itself alone.
Baruch SpinozaWhatever increases, decreases, limits or extends the body's power of action, increases decreases, limits, or extends the mind's power of action. And whatever increases, decreases, limits, or extends the mind's power of action, also increases, decreases, limits, or extends the body's power of action.
Baruch SpinozaBe not astonished at new ideas; for it is well known to you that a thing does not therefore cease to be true because it is not accepted by many.
Baruch Spinoza