To love one person productively means to be related to his human core, to him as representing mankind. Love for one individual, in so far as it is divorced from love for man, can refer only to the superficial and to the accidental; of necessity it remains shallow.

But not only medicine, engineering, and painting are arts; living itself is an art in fact, the most important and at the same time the most difficult and complex art to be practiced by man.

Man can only know the nagation, never the position of ultimate reality.

Just as love is an orientation which refers to all objects and is incompatible with the restriction to one object, so is reason a human faculty which must embrace the whole of the world with which man is confronted.

Politics and religious leaders [are hindered] by their egotism.

In the nineteenth century the problem was that God is dead. In the twentieth century the problem is that man is dead.

One cannot be deeply responsive to the world without being saddened very often.