 Because Leibniz was a mathematical novice when he first wrote about the "characteristic", at first he did not conceive it as an algebra but rather as a universal language or script.Only in 1676 did he conceive of a kind of "algebra of thought", modeled on and including conventional algebra and its notation.The resulting "characteristic" included a logical calculus, some combinatorics, algebra, his "analysis situs" (geometry of situation), a universal concept language, and more.