Each waking day is a stage dominated for good or ill, comedy, farce, or tragedy, by a dramatis personae, the 'self', and so it will be until the curtain drops.

The brain is a mystery; it has been and still will be. How does the brain produce thoughts? That is the central question and we have still no answer to it.

As followers of natural science we know nothing of any relation between thoughts and the brain, except as a gross correlation in time and space.

Swiftly the head mass becomes an enchanted loom where millions of flashing shuttles weave a dissolving pattern, always a meaningful pattern though never an abiding one...

The terminal path may, to distinguish it from internuncial common paths, be called the final common path. The motor nerve to a muscle is a collection of such final common paths.

With the nervous system intact the reactions of the various parts of that system, the 'simple reflexes', are ever combined into great unitary harmonies, actions which in their sequence one upon another constitute in their continuity what may be termed the 'behaviour'.

This integrative action in virtue of which the nervous system unifies from separate organs an animal possessing solidarity, an individual, is the problem before us.