We cannot predict the effects of our actions, especially our collective actions over generations or centuries, to use instrumental reasoning toward these big final ends to tell us what we ought to do.

Kant says that we may regard ourselves as legislator of the moral law, and consider ourselves as its author, but not that we are legislators or authors of the law.

Being aware of truths about what is good or right or about what we ought to do is not the same as deciding what to do. Nor can the former truths be derived from decisions about what to do, or about procedures for making such decisions, unless these procedures themselves rest in some way on the apprehension of truths about what we ought to do.

It is sad to witness the persistence in our society of the racism and xenophobia that seems to be a permanent part of our political culture. It is shameful to see politicians exploiting these human weaknesses in order to gain political power. It is most depressing of all to contemplate a future in which politicians who do this will continue to have influence over people's lives.

It was an important part of Mendelssohn's philosophical and religious view that the traditional rationalist proofs for God's existence should be sound an convincing. Kant thought they were not. So Kant's critique was world-shaking for Mendelssohn.

Kant did think he had a moral route back to rational faith in God, for those who need it, and he thought that at some level, we all do need something like it.

Kant can provide, and has provided, a good model for philosophers to think about the relation of metaphysics to science and scientific methodology.