Who said “I am certain of nothing but the holiness of the heart's affections, and the truth of…”?

“If you do know that here is one hand, we'll grant you all the rest.”

“In this world nothing can be said to be certain, except death and taxes.”

“It is the dull man who is always sure, and the sure man who is always dull.”

“The best lack all conviction, while the worst are full of passionate intensity.”

“Ah, what a dusty answer gets the soul when hot for certainties in this our life!”

“I always made an awkward bow.”

“I would sooner fail than not be among the greatest.”

“There is not a fiercer hell than the failure in a great object.”

“Beauty is truth, truth beauty -- that is all ye know on earth, and all ye need to know.”

“Nothing ever becomes real till it is experienced -- even a proverb is no proverb to you till your life has illustrated it.”

“Praise or blame has but a momentary effect on the man whose love of beauty in the abstract makes him a severe critic on his own works.”