Critics of President Obama's pick for the US Supreme Court are trying to turn the assertion that Sonia Sotomayor is "empathetic" into a negative.

And yet there is research into moral psychology dating back at least as far as Adam Smith's Theory of Moral Sentiments that makes clear the role of empathy in ethical decision making (see reading list below).

The Right's advocacy against Ms Sotomayor's nomination echoes advocacy of a free market ideology and institutions that work to create as much emotional distance as possible between decision makers and their impacts - see, for example, the insistence that corporate executives are obliged to consider the impacts of their decisions on nobody but their shareholders, so creating an ethics-free zone within business regarding executive's impacts on anyone else.

Markets are not efficient; rarely is there anything even approaching perfect information or perfect competition. Decision makers exercise discretion, decisions are and should be made with more than self-interest in mind and we need to recognize and support that ethical discretion.

In judging, too, we are not dealing with a machine. The common law tradition of which the US legal system is a strong, innovative contributor derives its strength from its ability to evolve to meet new challenges. The law only ever - even on appeal on a point of law - takes us so far, after which judges make it up. We should be very concerned to ensure they have the skills to do so, including empathy.

Empathy is necessary for our discernment of moral knowledge, and indeed justice itself.

While Ms Sotomayor's critics call for the exclusion of all concerns from the work of a Supreme Court justice but (presumably) literal constitutional interpretation, they would do well to remember that freedom of conscience is also a constitutional right.

Selected reading on empathy in ethical decision-making and law:

Good introductions include Primates and Philosophers - How Morality Evolved by Frans de Waal and Moral Minds - The Nature of Right and Wrong by Marc Hauser.

Then you might take a look at Adam "Wealth of Nations" Smith's The Theory of Moral Sentiments

For really serious days of study take a look at The Emotional Construction of Morals by Jesse Prinz and/or The Evolution of Morality by Richard Joyce.

And I for one would love to hear what Brian Leiter has to say about the Sotomayor nomination. Mr Leiter is author of Naturalizing Jurisprudence - Essays on American Legal Realism and Naturalism in Legal Philosophy.