Enthusiasm, being the infirmity of bold and ambitious tempers, is naturally accompanied with a spirit of liberty; as superstition,on the contrary, renders men tame and abject, and fits them for slavery.

The fact that different cultures have different practices no more refutes [moral] objectivism than the fact that water flows in different directions in different places refutes the law of gravity

A wise man proportions his belief to the evidence.

It forms a strong presumption against all supernatural and miraculous relations, that they are observed chiefly to abound among ignorant and barbarous nations; or if a civilized people has ever given admission to any of them, that people will be found to have received them from ignorant and barbarous ancestors.

The heart of man is made to reconcile the most glaring contradictions.

When I am convinced of any principle, it is only an idea which strikes more strongly upon me. When I give the preference to one set of arguments above another, I do nothing but decide from my feeling concerning the superiority of their influence.

Scholastic learning and polemical divinity retarded the growth of all true knowledge.