"It is not in the power of any created being to make things true or false, but only to discover what is true or false."

"The motion of the earth is a fact, not a theory."

"The authority of a thousand is not worth the humble reasoning of a single individual who observes the facts."

"It is a great pity that there are so few who are interested in the true causes of things."

"It is surely harmful to souls to make it a heresy to believe what has been proved."