Man has been called a rational being, but rationality is a matter
of choice -- and the alternative his nature offers him is: rational
being or suicidal animal. Man has to be man -- by choice; he has
to hold his life as a value -- by choice; he has to learn to sustain
it -- by choice; he has to discover the values it requires and
practice his virtues -- by choice.
A code of values accepted by choice is a code of morality.
-- John Galt