I think it would be just to say the most essential characteristic of mind is memory, using this word in its broadest sense to include every influence of past experience on present reactions.
Bertrand RussellEver since men became capable of free speculation, their actions, in innumerable important respects, have depended upon their theories as to the world and human life, as to what is good and what is evil. This is true in the present day as at any former time. To understand an age or a nation, we must understand its philosophy, and to understand its philosophy we must ourselves be in some degree philosophers. There is here a reciprocal causation: the circumstances of men s lives do much to determine their philosophy, but, conversely, their philosophy does much to determine their circumstances.
Bertrand RussellFrom that awful encounter of the soul with the outer world, enunciation, wisdom, and charity are born; and with their birth a new life begins. To take into the inmost shrine of the soul the irresistible forces whose puppets we seem to be - Death and change, the irrevocableness of the past, and the powerlessness of Man before the blind hurry of the universe from vanity to vanity - to feel these things and know them is to conquer them.
Bertrand Russell