In order to critique Rawls' arguments for the Difference Principle (DP), we must first begin by clarifying the building blocks of his theory of justice. Firstly, Rawls proposes the notion of an original position which places one behind the veil of ignorance. Behind this veil, one is not privy to the knowledge of one's sex, race, physical condition, family background etc. The only knowledge one possesses is that of the different situations humans may be placed in, and the general facts about human psychology and nature. Rawls argues that self-interested, rational individuals would ultimately choose two principles of justice to structure society in reality.
The first principle of justice is that of equal liberty, i.e. Each person has an equal right to the most extensive liberties compatible with a similar liberties for all. The second principle states that social and economic inequalities are to be arranged so that they are both: (a) to the greatest benefit of the least advantaged, and (b) attached to offices and positions open to all under conditions of fair equality of opportunity.
From this principle, Rawls is essentially egalitarian in asserting that all inequalities as unjust except insofar as it is an essential means to improving the position of the worst-off in society. However, Rawls is also departing from strict egalitarianism by claiming that justices does not necessarily require equality - inequalities may exist, justified as incentives; e.g. if distributing more power, income etc. to certain people ensues in a higher living standards for all in the community, benefiting also the least advantaged, justice is achieved. This is Rawls' belief in the 'trickle-down effect' as a justification of inequality; that as long as the least advantaged are made better off, a grossly unequal increment of wealth to even just one person can be...