QUOTE : it is still rare to find a philosopher or a psychologist who fully comprehends that he is consuming the fruits of this long, agonizing struggle to state the exact relation between spirit and matter, every time he uses such key-words of thought as absolute, actual, attribute, cause, concept, deduction, essence, existence, intellect, intelligence, intention, intuition, motive, potential, predicate, substance, tendency, transcend; abstract and concrete, entity and identity, matter and form, quality and quantity, objective and subjective, real and ideal, general, special and species, particular, individual, and universal.