Skepticism is the highest duty and blind faith the one unpardonable sin.

I doubt the fact, to begin with, but if it be so even, what is this but in grand words asking me to believe a thing because I like it.

Only a scientific people can survive in a scientific future.

There is no greater mistake than the hasty conclusion that opinions are worthless because they are badly argued.

Unfortunately, it is much easier to shut one's eyes to good than to evil. Pain and sorrow knock at our doors more loudly than pleasure and happiness; and the prints of their heavy footsteps are less easily effaced.

'Infidel' is a term of reproach, which Christians and Mohammedans, in their modesty, agree to apply to those who differ from them.

There is but one right, and the possibilities of wrong are infinite.