Now the good of political life is a great political good. It is not a secular good specified by a comprehensive doctrine like those of Kant or Mill. You could characterize this political good as the good of free and equal citizens recognizing the duty of civility to one another: the duty to give citizens public reasons for one's political actions.

The bad man desires arbitrary power. What moves the evil man is the love of injustice.

A political conception just applies to the basic structure of a society, its institutions, constitutional essentials, matters of basic justice and property, and so on.

The hazards of the generalized prisoner's dilemma are removed by the match between the right and the good.

An intuitionist conception of justice is, one might say, but half a conception.

What's important is that people give the kinds of reasons that can be understood and appraised apart from their particular comprehensive doctrines: for example, that they argue against physician-assisted suicide not just by speculating about God's wrath or the afterlife, but by talking about what they see as assisted suicide's potential injustices.

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.