The Genius of Kinship: The Phenomenon of Human Kinship and the G ...

Chapter 3

Logic, Semiotics,
and Reproduction

Augustus De Morgan, Charles Peirce,
Francis Galton, and Karl Pearson:
Logical Relations, Semiotic Iconicity,
and Statistical Correlation

Nowhere in anthropological literature can one find a reference to a work by the great British logician, Augustus De Morgan, entitled On the Syllogism, No. IV, and on the Logic of Relations (De Morgan, 1859b; see also De Morgan, 1860). De Morgan's article is simultaneously a foundational text on the logic of relations forming a bridge between classical and modern logic (see Gottschall, 1980)¹ and a treatise on kin terms, for, as De Morgan himself pointed out twice (De Morgan, 1859b, pp. 335, 341), “consanguinity and affinity” almost monopolized” (“appropriated”) the very name “relations.” De Morgan was reworking the Aristotelian theory of syllogism, for, as he noted, it allows one to distinguish truth from falsehood, but it cannot “either distinguish or evolve one truth from another” (De Morgan, 1859b, p. 335). In other words, logic should shift from the study