“It must be confessed, moreover, that perception, and that which
depends on it, are inexplicable by mechanical causes, that is, by
figures and motions. And, supposing that there were a mechanism so
constructed as to think, feel and have perception, we might enter it as
into a mill. And this granted, we should only find on visiting it,
pieces which push one against another, but never anything by which to
explain a perception. This must be sought, therefore, in the simple
substance, and not in the composite or in the machine.”