Since knowledge, thinking, and rational action are properties of the individual, since the choice to exercise his rational faculty or not depends on the individual, man's survival requires that those who think be free of the interference of those who don't.

Since men are neither omniscient no infallible, they must be free to agree or disagree, to cooperate or to pursue their own independent course, each according to his own rational judgement. Freedom is the fundamental requirement of man's mind. A rational mind does not work under compulsion; it does not subordinate its grasp of reality to anyone's orders, directives, or controls; it does not sacrifice its knowledge, its view of the truth, to anyone's opinions, threats, wishes, plans, or "welfare".

Such a mind may be hampered by others, it may be silenced, proscribed, imprisoned, or destroyed; it cannot be forced; a gun is not an argument. (An example and symbol of this attitude is Galileo.)

~ Ayn Rand (Capitalism - The Unknown Ideal)