Phaneroscopy: A Science of Diagrams

In the last decade of his life, Peirce developed phaneroscopy and existential graphs as the basis for a proof of pragmaticism. To publish the proof, he wrote a series of articles for the Monist. The first two began with phaneroscopy. But in 1906, he added a version of tinctured existential graphs to the third article, An Apology for Pragmaticism. In 1908, he began a fourth article, which he never finished. One reason he stopped may be his remark in 1909: “Phaneroscopy, still in the condition of a science-egg, hardly any details of it being as yet distinguishable.” Other reasons involve issues about the graphs, which he resolved in 1911. Although Peirce did not complete the proof, his writings inspired aspects of Lady Welby’s significs, Wittgenstein’s language games, and patterns of diagrams in every branch of science and engineering. Today, Peirce’s theories of phaneroscopy and diagrammatic reasoning address fundamental issues in linguistics, neuroscience, and artificial intelligence.