  Finally, John Venn (1834–1923) has to be mentioned. His Symbolic Logic (1881) is important for the historical contextualization of the new logic. He criticized Jevons’ statement on the Law of Duality according to which “the late Professor Boole is the only logician in modern times who has drawn attention to this remarkable property of logical terms” as being simply false. Besides, Leibniz, Lambert, Ploucquet and Segner had anticipated the law “perfectly explicitly” and he had no doubts “that any one better acquainted than myself with the Leibnitzian and Wolfian logicians could add many more such notices” (Venn 1881, xxxi, footnote 1).