Isaac Newton — "What goes up must come down."

"A man may imagine things that are false, but he can only understand things that are true, for if the things be false, the apprehension of them is not understanding."

"To explain all nature is too difficult a task for any one man or even for any one age. 'Tis much better to do a little with certainty, & leave the rest for others that come after you, than to explain …"

"It is possible that gravity may be essential to matter."

"For if the experiments which I relate be accurate, the science of colours will be a new one; for although colours have been observed from antiquity, yet the cause of their productions has remained unk…"

"The greatest challenges to the truth of the Holy Scriptures are not the work of infidels, but of professing Christians."