If I have a book that thinks for me, a pastor who acts as my conscience, a physician who prescribes my diet, and so on... then I have no need to exert myself. I have no need to think, if only I can pay; others will take care of that disagreeable business for me.

The true religion is to be posited not in the knowledge or confession of what God allegedly does or has done for our salvation, but in what we must do to become worthy of this.

But, above all, it will confer an inestimable benefit on morality and religion, by showing that all the objections urged against them may be silenced for ever by the Socratic method, that is to say, by proving the ignorance of the objector.

...[M]oral instruction, although containing much that is convincing for the reason, ...accomplishes... little... [because] the teachers themselves have not got their own notions clear, and when they endeavor to make up for this by raking up motives of moral goodness from every quarter, trying to make their physic right strong, they spoil it.

The main point of enlightenment is man's release from his self-caused immaturity, primarily in matters of religion.

He who has made great moral progress ceases to pray