Automata, reason, and free will: Leibniz's critique of Descartes on animal and human nature.

This paper argues that Leibniz's use of the concept of "automaton" to characterize the nature of souls and bodies of living beings constitutes a systematic critique of Descartes' earlier use of automata. Whereas Descartes conceived non-human animals in terms of mechanical automata, he also denied that the human rational soul can be modeled on the nature of an automaton. In contrast, Leibniz understood living things to involve both an organic body, or "natural automaton," as well as an immaterial soul, or "spiritual automaton," that spontaneously produces its own perceptions. In extending the concept of the automaton to souls, Leibniz rejected key Cartesian assumptions about animals and free will and draws on the concept of the automaton to understand a range of cognitive capacities including volition. Leibniz thus occupies a distinctive place in the history of the use of automata to understand the nature of living things.