To the very last...................

 

     When Einstein died, his greatest rival, Bohr, found for him words of moving admiration.*  When a few years later Bohr in turn died, someone took a photograph of his blackboard in his study.  There's a drawing on it.  A drawing of the "light-filled box" in Einstein's thought experiment.  To the very last, the desire to challenge one-self and understand more.  And to the very last: doubt.

-Carlo Rovelli, Seven Brief Lessons on Physics

*"With the death of Albert Einstein, a life in the service of science and humanity which was as rich and fruitful as any in the whole history of our culture has come to an end. Mankind will always be indebted to Einstein for the removal of the obstacles to our outlook which were involved in the primitive notions of absolute space and time." -Niels Bohr