- Liberalism: A single human world ordered only by reason, based on pure (content-free) concepts. Freedom says you ignore the content of human goals and promote all of them simply as such, and equality says you ignore the content of human qualities so you treat all men as equal in value. Put them together and you get liberalism.
- Islam: A single human world ordered by pure will. There’s no place for reason, since God, who acts by arbitrary choice and is not bound by reason, is the immediate cause of everything.
- Judaism: Two parallel human worlds, the public world everyone is part of that can be appropriately ordered by pure reason, and a private Jewish world ordered by will in the form of a contract between God and the Jewish people that imposes arbitrary conditions like keeping kosher.
- Catholicism: Two human worlds, the order of nature and the order of grace, that are conceptually distinct but cannot be separated without violence because they are part of a single rational divine order: grace completes nature, and is meant for all.
To the extent the foregoing schema approximates reality, it appears that Islam and liberalism are direct mortal foes, while Judaism and liberalism are natural allies, since liberalism gives the Jews a secure and equal position and Judaism gives them what liberalism lacks as the basis for a complete life. Catholicism and liberalism can work together on some practical issues but in the long run are irreconcilable since the conceptions of reason and reality are different—Catholic reason has natural-law content, liberal reason does not.