Rawls ignited a debate in political theory when he introduced a division between
the ideal and nonideal parts of a theory of justice. In the ideal part of the
theory, one presents a positive conception of justice in a setting that assumes
perfect compliance with the rules of justice. In the nonideal part, one
addresses the question of what happens under departures from compliance. Critics
of Rawls have attacked his focus on ideal theory as a form of utopianism, and
have argued that political theory should be focused instead on providing
solutions to the manifest injustices of the real world. In this essay, I offer a
defense of the ideal/nonideal theory distinction according to which it amounts
to nothing more than a division of labor, and explore some scientific analogies.
Rawls’s own focus on the ideal part of the theory, I argue, stems
from a felt need to clarify the foundations of justice, rather than a utopian
neglect of real world problems.