SEMANTICS OF THE DIFFERENTIAL CALCULUS 579
higher centres, further removed, and not in direct contact with the world around us. With the finite velocity of nerve currents it takes 'time' for impulses to reach these centres, as the cortical pathways offer higher neural resistances than the other pathways.8 So there has to be a survival mechanism in the production of nervous means for arresting the stream of events and producing static pictures of permanent character, which may allow us to investigate, verify, analyse , . It must be noticed that because of this higher neural resistance of higher centres and the static character of the higher abstractions, these abstractions are less distorted by affective moods. For, since the higher abstractions persist, if we care to remember them, and the moods vary, we can contemplate the abstractions under different moods and so come to some average outlook on a given problem. It is true that we seldom do this, but we may do it, and this is of importance to us.