It must be confessed, moreover, that perception, & that which depends on it, are inexplicable by mechanical causes, that is, by figures & motions, And, supposing that there were a mechanism so constructed as to think, feel & 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, & not in the composite or in the machine. — Gottfried Leibniz, Monadology, sect. 17
Except that is not true. Single-celled organisms perform independent acts. That may be tiny, but it is intelligence. Every living being more complex than that is built from that smallest bit of intelligence.
