“Reason obeys itself; and ignorance submits to whatever is dictated to it.”

“Ignorance is of a peculiar nature; once dispelled, it is impossible to reestablish it. It is not originally a thing of itself, but is only the absence of knowledge; and though man may be kept ignorant, he cannot be made ignorant.”

“Where knowledge is a duty, ignorance is a crime.”

“It is only by the exercise of reason that man can discover God. Take away that reason, and he would be incapable of understanding anything; and, in this case, it would be just as consistent to read even the book called the Bible to a horse as to a man. How, then, is it that those people pretend to reject reason?”

“Of all the systems of religion that ever were invented, there is no more derogatory to the Almighty, more unedifying to man, more repugnant to reason, and more contradictory to itself than this thing called Christianity. Too absurd for belief, too impossible to convince, and too inconsistent for practice, it renders the heart torpid or produces only atheists or fanatics. As an engine of power, it serves the purpose of despotism, and as a means of wealth, the avarice of priests, but so far as respects the good of man in general it leads to nothing here or hereafter.”

“Time makes more converts than reason.”

“Whatever is my right as a man is also the right of another; and it becomes my duty to guarantee as well as to possess.”