Man’s rights can be violated only by the use of physical force. It is only by
means of physical force that one man can deprive another of his life, or
enslave him, or rob him, or prevent him from pursuing his own goals, or compel
him to act against his own rational judgment.
The precondition of a civilized society is the barring of physical force from
social relationships—thus establishing the principle that if men wish to deal
with one another, they may do so only by means of reason: by discussion,
persuasion and voluntary, uncoerced agreement.