Love can flourish only as long as it is free and spontaneous; it tends to be killed by the thought of duty. To say that it is your duty to love so-an… - Bertrand Russell

So much of modern mathematical work is obviously on the border-line of logic, so much of modern logic is symbolic and formal, that the very close relationship of logic and mathematics has become obvious to every instructed student. The proof of their identity is, of course, a matter of detail: starting with premisses which would be universally admitted to belong to logic, and arriving by deduction at results which as obviously belong to mathematics, we find that there is no point at which a sharp line can be drawn, with logic to the left and mathematics to the right. If there are still those who do not admit the identity of logic and mathematics, we may challenge them to indicate at what point, in the successive definitions and deductions of Principia Mathematica, they consider that logic ends and mathematics begins. It will then be obvious that any answer must be quite arbitrary.

I don't care for the applause one gets by saying what others are thinking; I want actually to change people's thoughts. Power over people's minds is the main personal desire of my life; and this sort of power is not acquired by saying popular things.

All the time that he can spare from the adornment of his person, he devotes to the neglect of his duties.