Freedom of mind is the real freedom. A person whose mind is not free though he may not be in chains, is a slave, not a free man. One whose mind is not free, though he may not be in prison, is a prisoner and not a free man. One whose mind is not free though alive, is no better than dead. Freedom of mind is the proof of one's existence.
"Political Science for Civil Services Main Examination". Book by N.D. Arora, 2010.