The veil of ignorance, explained

The veil of ignorance is a thought experiment from the philosopher John Rawls, used to test whether a set of rules is fair. Imagine you must choose the basic rules of a society without knowing who you will be in it: your wealth, your abilities, your family, your health, your beliefs. Rawls called this the original position.

The idea is that, behind the veil, you cannot design rules to favour yourself, so you are pushed to think about fairness for everyone. Rawls argued that people choosing in such a position would protect basic liberties and would accept inequalities only if they work to the benefit of the least advantaged.

It is a useful tool even for people who reject Rawls's conclusions. Whenever we judge a policy, we can ask: would I accept this if I did not know which position I would occupy?

Limits and criticisms: some argue that people would reason about risk differently from how Rawls assumes, that the experiment hides too much of what makes us who we are, and that it works better for institutions than for personal choices.

Used as a prompt for reflection, it is hard to beat.