During his lectures, von Foerster discusses the central nervous system from several perspectives, presented here in the following order: 1) anecdotal and historical material illustrating the perennial debate over the location of man’s consciousness—in other words, which bodily organ is responsible for the higher mental functions; 2) the evolution of the “internuncial” which links our sensory and motor systems; 3) the structure and function of the neuron, the nervous system’s basic component.