Die Leibniz-Handschriften der Königlichen Öffentlichen Bibliothek
Eduard Bodemann (ed)
p 56

Sämtliche schriften und briefe series VI volume 4
Deutsche Akademie der Wissenschaften (ed)
p 1474

Date: 1683 - 1685?

Translated from the Latin

View this translation in PDF format (151k)

Back to home page

Search texts by keyword(s):

(For search strings, just type the words; don't use quotation marks)


[BH p56] [A VI 4, p1474]

     I suspect the opinion of the Cartesians may eventually be refuted by experience if men were to take greater pains in training animals. When writing to More, Descartes correctly asserts that he knows demonstratively that all the actions of beasts can be explained without invoking souls, just as [he knows] the contrary cannot be demonstrated,1 but this should be understood according to metaphysical rigour, whereby it cannot be demonstrated of other men either.


1. "there are two different principles causing our movements. The first is purely mechanical and corporeal, and depends solely on the force of the spirits and the structure of our organs, and can be called the corporeal soul. The other, an incorporeal principle, is the mind or that soul which I have defined as a thinking substance. Thereupon I investigated very carefully whether the movements of animals originated from both of these principles or from one only. I soon perceived clearly that they could all originate from the corporeal and mechanical principle, and I regarded it as certain and demonstrated that we cannot at all prove the presence of a thinking soul in animals... But though I regard it as established that we cannot prove there is any thought in animals, I do not think it can be proved that there is none, since the human mind does not reach into their hearts." Descartes, Letter to Henry More 5 February 1649 in John Cottingham, Robert Stoothoff, Dugald Murdoch & Anthony Kenny (eds), The Philosophical Works of Descartes Vol. III (Cambridge: Cambridge University Press, 1991), 365.

© Lloyd Strickland 2005. Revised 2021