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.

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.

How did Madison get separation through Virginia and later Congress? The Baptists, the Presbyterians, and the smaller sects hated Jefferson; to them he was a secularist of the worst kind. But Madison could get Jefferson's bill passed because the Baptists, the Presbyterians, and smaller sects who were excluded in New England and in the South got together for their own protection.

An injustice is tolerable only when it is necessary to avoid an even greater injustice.

Certainly it is wrong to be cruel to animals and the destruction of a whole species can be a great evil. The capacity for feelings of pleasure and pain and for the form of life of which animals are capable clearly impose duties of compassion and humanity in their case.

The good of political life is the good of free and equal citizens recognizing the duty of civility to one another and supporting the institutions of a constitutional regime.

A comprehensive doctrine, either religious or secular, aspires to cover all of life. I mean, if it's a religious doctrine, it talks about our relation to God and the universe; it has an ordering of all the virtues, not only political virtues but moral virtues as well, including the virtues of private life, and the rest. Now we may feel philosophically that it doesn't really cover everything, but it aims to cover everything, and a secular doctrine does also.