In the absence of this strange intoxication that outsiders greet with a pitying smile, without this passion, this conviction that ‘millennia had to pass before you were born, and millennia more must wait in silence’ to see if your conjecture will be confirmed–without this you do not possess this vocation for science and should turn your hand to something else. For nothing has any value for a human being as a human being unless he can pursue it with passion.