(earth-air, fire-water). At the four corners of the superimposed square are the four qualities defining the elements. Each adjacent pair of these is joined by a bar labeled "possible combination"; the diagonals joining them are labeled "impossible combination". Starting from the top, fire is formed from the combination of dryness and heat; air from wetness and heat; water from coldness and wetness; earth from coldness and dryness. This diagram is reproduced in several texts including Saemtliche Schriften und Briefe (Saemtliche Schriften und Briefe, Reihe VI, Band 1: 166, Loemker 1969: 83, 366, Karl Popp and Erwin Stein 2000: 33). Leibniz retraces his steps and makes a discovery Leibniz rightly saw that creating the characteristica would be difficult, fixing the time required for devising it as follows: "I think that some selected men could finish the matter in five years" (Loemker 1969: 224), later remarking: "And so I repeat, what I have often said, that a man who is neither a prophet nor a prince can ever undertake any thing of greater good to mankind of more fitting for divine glory" (Loemker 1969: 225). But later in life, a more sober note emerged. In a March 1706 letter to the Electress Sophia of Hanover, the spouse of his patron, he wrote: In another 1714 letter to Nicholas Remond, he wrote: Eventually, by discovering binary digits again from Chinese works, which was now from the I Ching, Leibniz arrived at what he felt was a discovery of a link that would thereby create his characteristica universalis. It eventually created the foundations of symbolic logic and modern philosophy, specifically the predicate-based Analytic Philosophy and Boolean Logic. Three criteria C. J. Cohen (1954) set out three criteria which any project for a philosophical language would need to meet before it could be considered a version of the characteristica universalis. In setting out these criteria, Cohen made reference to the concept of "logistic". This concept is not the same as that used in statistical analysis. In 1918, Clarence Irving Lewis, the first English-speaking logician to translate and discuss some of Leibniz's logical writings, elaborated on "logistic" as follows: Following from this Cohen stipulated that the universal character would have to serve as: An "international auxiliary language" enabling individuals speaking different languages to communicate with one another; Symbolism for the exact and systematic expression of all present knowledge, making possible a "logistic" treatment of science in