NotaBene .

The Universal Language: Descartes's Skepticism and Leibniz's Optimism

Abstract: The paper is a commentary to the translation of the famous letter of 20th November 1629 written by Descartes to Father Mersenne on the possibility, or rather impossibility, for universal language to be constructed. Descartes states his sceptic position that without the 'true philosophy' which should provide the primitive ideas out of which all thoughts can be constructed, and without firm knowledge of the order in which our thoughts go through the mind he has no hope to ever see such language in use. Leibniz, on the contrary, optimistically invents his theory of 'blind thought' (cognitatio caeca) believing that it removes the difficulties raised by Descartes. Lastly, the paper surveys in brief the influence of Leibniz's Characteristica universalis on Frege and the production of his first masterpiece Concept-script (Begriffsschrift), 1879.

Key words: Characteristica universalis, blind thought, Descartes, Leibniz, Hobbes