# Question about Leibniz's "characteristic numbers" and propositional logic

The Wikipedia article on Gottfried Wilhelm Leibniz mentions, in the chapter on symbolic thought, that:

Leibniz saw that the uniqueness of prime factorization suggests a central role for prime numbers in the universal characteristic, a striking anticipation of Gödel numbering. Granted, there is no intuitive or mnemonic way to number any set of elementary concepts using the prime numbers.

First of all, as far as I understand, Gödel numbering is an operation that does assign a prime number to every elementary symbol (or the elementary concept it represents) or logical operation (such as logical conjunction) , and therefore the second sentence is unclear to me.

Secondly, I'd like to get a reference about the manuscripts in which Leibniz anticipated Gödel numbering (of which the wikipedia claim is based). I guess it's in of his writings on "characteristic numbers" and the "calculus of propositions", but the Leibniz's nachlass is too vast and i don't know where to find the relevant material.

Everyone with useful information is welcome to contribute to the answer of my question.

• leibnizedition.de/reihen/reihe-vi Commented Sep 29, 2018 at 18:34
• Best place currently is the Akademie Ausgabe, perhaps VI.4 A ( leibnizedition.de/reihen/reihe-vi ); Regulae ex quibus de bonitate consequentiarum judicari potest per numerum, p.242 Commented Sep 29, 2018 at 18:40
• The link with memeory is exactly what is not relevant for Gödel's Arithmetization of syntax. Commented Sep 30, 2018 at 8:45
• Gödel numbering is a rather arbitrary way of assigning numbers to sentences of a particular formal language (Principia Mathematica originally, later Peano arithmetic), even if it did assign primes to primitives it would hardly be "intuitive or mnemonic". Leibniz would need some intrinsic relation between primitive concepts themselves (if there was such a thing), not formal sentences, and primes to assign the numbers canonically. Commented Sep 30, 2018 at 21:03
• On Gödel's obsession with characteristica universalis and paranoia about Leibniz see Why did Gödel believe that there was a conspiracy to suppress Leibniz's works? Dawson's book cited there mentions Leibniz's works that Gödel considered relevant. Commented Oct 1, 2018 at 3:07