I appeal to your own eyes as my witness and judge. - William Harvey

...I found the task so truly arduous... that I was almost tempted to think... that the movement of the heart was only to be comprehended by God. For I could neither rightly perceive at first when the systole and when the diastole took place by reason of the rapidity of the movement...

I avow myself the partisan of truth alone.

Very many maintain that all we know is still infinitely less than all that still remains unknown.