ABSTRACT
The brain is linked by ordinary physical relations with the rest of the body, and so more remotely with the rest of the physical world, and these relations determine its behaviour. Each brain process is caused by other physical processes in its neighbourhood, and affects them in its turn. The correlations could exist if the brain-state determined the mind-state, or if the mind-state determined the brain-state, or and if both mental and physical causes were operative at each stage of the process, jointly determining both mental and physical effects. The brain responds in a very complex fashion to a great number of stimuli, instead of responding in a stereotyped fashion to one small group of stimuli. The animal body, in sleep and in its manifold unconscious operations, pursues the same kind of activity, the conversion of alien matter into parts of itself.
