#Certainty

"You’ve got to be sure of yourself beforeYou can ever win a prize."

"Science says the first word on everything, and the last word on nothing."

"If you do not know where you come from, then you don't know where you are, and if you don't know where you are, then you don't know where you're going. And if you don't know where you're going, you're probably going wrong."

"In our reasonings concerning matter of fact, there are all imaginable degrees of assurance, from the highest certainty to the lowest species of moral evidence. A wise man, therefore, proportions his belief to the evidence."

"The devil's happy when the critics run you off."