But from the similar mode of activity on the part of the lower animals, the source of which we are unable directly to perceive, compared with that of man, of which we are immediately conscious, we may quite correctly infer, on the strength of the analogy, that the lower animals, like man, act according to representations, and are not machines, as Descartes contends, and that, despite their specific difference, they are living beings and as such generally kindred to man.