There are two kinds of comprehensive doctrines, religious and secular. Those of religious faith will say I give a veiled argument for secularism, and the latter will say I give a veiled argument for religion. I deny both. Each side presumes the basic ideas of constitutional democracy, so my suggestion is that we can make our political arguments in terms of public reason. Then we stand on common ground. That's how we can understand each other and cooperate.

The circumstances of justice may be described as the normal conditions under which human cooperation is both possible and necessary.

The principles of justice are chosen behind a veil of ignorance.

Ideally citizens are to think of themselves as if they were legislators and ask themselves what statutes, supported by what reasons satisfying the criterion of reciprocity, they would think is most reasonable to enact.

Justice is the first virtue of social institutions, as truth is of systems of thought. A theory however elegant and economical must be rejected or revised if it is untrue; likewise laws and institutions no matter how efficient and well-arranged must be reformed or abolished if they are unjust.

Justice is happiness according to virtue.

Any comprehensive doctrine, religious or secular, can be introduced into any political argument at any time, but I argue that people who do this should also present what they believe are public reasons for their argument. So their opinion is no longer just that of one particular party, but an opinion that all members of a society might reasonably agree to, not necessarily that they would agree to. What's important is that people give the kinds of reasons that can be understood and appraised apart from their particular comprehensive doctrines.