can never be reduced to physics, but

their arguments are not very convincing and it seems prudent to suppose that they are mistaken. What we call our "thoughts" seem to depend upon the organization of tracks in the brain in the same sort of way in which journeys depend upon roads and railways. The energy used in thinking seems to have a chemical origin; for instance, a deficiency of iodine will turn a clever man into an idiot. Mental phenomena seem to be bound up with material structure. If this be so, we cannot suppose that a solitary electron or proton can "think"; we might as well expect a solitary individual to play a football match. We also cannot suppose that an individual's thinking survives bodily death, since that destroys the organization of the brain, and dissipates the energy which utilized the brain-tracks.