From Economic Theories of Social Justice: Risk, Value, and Externality
, by Anthony de Jasay:
Stripped of rhetoric, an act of social justice (a) deliberately increases the relative share…of the worse-off in total income, and (b) in achieving (a) it redresses part or all of an injustice….This implies that some people being worse off than others is an injustice and that it must be redressed. However, redress can only be effected at the expense of the better-off; but it is not evident that they have committed the injustice in the first place. Consequently, nor is it clear why the better-off should be under an obligation to redress it….
There is the view, acknowledged by de Jasay, that the better-off are better off merely because of luck. But as he points out:
Since Nature never stops throwing good luck at some and bad luck at others, no sooner are [social] injustices redressed than some people are again better off than others. An economy of voluntary exchanges is inherently inegalitarian....Striving for social justice, then, turns out to be a ceaseless combat against luck, a striving for the unattainable, sterilized economy that has built-in mechanisms...for offsetting the misdeeds of Nature.