If two angels were sent down from heaven -one to conduct an empire and the other to sweep the streets -they would feel no inclination to change employment because an angel would know that no matter what we are doing, it's an opportunity to bring joy, deepen our understanding and expand our life.

To myself I am only a child playing on the beach, while vast oceans of truth lie undiscovered before me

I do not know what I may appear to the world, but to myself I seem to have been only like a boy playing on the seashore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me.

I consider my greatest accomplishment to be lifelong celibacy.

Hypotheses non fingo. I frame no hypotheses.

You sometimes speak of gravity as essential and inherent to matter. Pray do not ascribe that notion to me, for the cause of gravity is what I do not pretend to know, and therefore would take more time to consider of it.

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.