In contrast, a number of other Enlightenment theorists (Adam Smith, Condorcet, Mary Wollstonecraft, Karl Marx and John Stuart Mill, for example) took a variety of approaches that shared an interest in making comparisons between different ways in which people's lives may go, jointly influenced by the working of institutions, people's actual behaviour, their social interactions, and other factors that significantly impact on what actually happens. The analytical, and rather mathematical, discipline of "social choice theory" – which can be traced to the works of Condorcet in the 18th century, but has been developed in the present form under the leadership of Kenneth Arrow in the last century – belongs to this second line of investigation. That approach, suitably adapted, can make a substantial contribution, I believe, to addressing questions about the enhancement of justice and the removal of injustice in the world.
In this alternative approach, we don't begin by asking what a perfectly just society would look like, but asking what remediable injustices could be seen on the removal of which there would be a reasoned agreement. "In the little world in which children have their existence," says Pip in Great Expectations, "there is nothing so finely perceived, and finely felt, as injustice." In fact, the strong perception of manifest injustice applies to adult human beings as well. What moves us is not the realisation that the world falls short of being completely just, which few of us expect, but that there are clearly remediable injustices around us which we want to eliminate.
Terrific piece by Amartya Sen in the Guardian, here.