THE book is not a treatise on aIl cerebral mechanisms but a pro- poscd
solution of a specific problem: the origin of the nervous system's
unique ability to produce adaptive behaviour. The work has as basis the
fact that the nervous system behaves adap- tively and the hypothesis
that it is essentiaIly mechanistic; it proceeds on the assumption that
these two data are not irrecon- cilable. It attempts to deduce from the
observed facts what sort of a mechanism it must be that behaves so
differently from any machinc made so far. Other proposed solutions have
usuaIly left open the question whether so me different theory might not
fit the facts equaIly weIl: I have attempted to deduce what is
necessary, what properties the nervous system must have if it is to
behave at once mechanisticaIly and adaptively. For the deduction to be
rigorous, an adequately developed logic of mechanism is essential. Until
recently, discussions of mechan- ism were carried on almost entirely in
terms of so me particular embodiment-the mechanical, the electronic, the
neuronie, and so on. Those days are past. There now exists a
weIl-developed logic of pure mechanism, rigorous as geometry, and likely
to play the same fundamental part, in our understanding of the complex
systems of biology, that geometry does in astronomy. Only by the
dcvelopment of this basic logic has thc work in this book been made
possible.
