A valid moral ideal, of course, must lie within the bounds of the metaphysically possible; a rational morality does not endeavor to attain what cannot be attained in reality. (Cf. the discussion of morality and practicality in pp. 3.7:1-8). The ideal of a free market falls within the metaphysically possible, since it requires only that human beings refrain from the initiation of force. Once some individuals have violated this principle, however, it may no longer be possible to repair the breaches perfectly. Rationally, we can then expect only that the criminal justice system will restore to victims of aggression the values taken from them, to the extent that such restoration remains possible.