Editing Theory of categories (section)

===Peirce===
{{main|Categories (Peirce)}}

[[Charles Sanders Peirce]], who had read Kant and Hegel closely, and who also had some knowledge of Aristotle, proposed a system of merely three phenomenological categories: [[Categories (Peirce)|Firstness, Secondness, and Thirdness]], which he repeatedly invoked in his subsequent writings. Like Hegel, C.S. Peirce attempted to develop a system of categories from a single indisputable principle, in Peirce's case the notion that in the first instance he could only be aware of his own ideas. 
	"It seems that the true categories of consciousness are first, feeling&nbsp;... second, a sense of resistance&nbsp;... and third, synthetic consciousness, or thought".<ref>''Op.cit.5'' p.200, cf Locke</ref>
	Elsewhere he called the three primary categories: [[Quality (philosophy)|Quality]], Reaction and [[Meaning (semiotics)|Meaning]], and even [[Categories (Peirce)|Firstness, Secondness and Thirdness]], saying, "perhaps it is not right to call these categories conceptions, they are so intangible that they are rather tones or tints upon conceptions":<ref>''Ibid.'' p.179</ref>     
*Firstness ([[Quality (philosophy)|Quality]]): "The first is predominant in feeling&nbsp;... we must think of a quality without parts, e.g. the colour of magenta&nbsp;... When I say it is a quality I do not mean that it "inheres" in a subject&nbsp;... The whole content of consciousness is made up of qualities of feeling, as truly as the whole of space is made up of points, or the whole of time by instants".
*Secondness (Reaction): "This is present even in such a rudimentary fragment of experience as a simple feeling&nbsp;... an action and reaction between our soul and the stimulus&nbsp;... The idea of second is predominant in the ideas of causation and of statical force&nbsp;... the real is active; we acknowledge it by calling it the actual".
*Thirdness ([[Meaning (semiotics)|Meaning]]): "Thirdness is essentially of a general nature&nbsp;... ideas in which thirdness predominate [include] the idea of a sign or representation&nbsp;... Every genuine triadic relation involves meaning&nbsp;... the idea of meaning is irreducible to those of quality and reaction&nbsp;... synthetical consciousness is the consciousness of a third or medium".<ref>''Ibid.'' pp.148-179</ref>

Although Peirce's three categories correspond to the three concepts of relation given in Kant's tables, the sequence is now reversed and follows that given by [[Science of Logic|Hegel]], and indeed before Hegel of the three moments of the world-process given by [[Neoplatonism|Plotinus]]. Later, Peirce gave a mathematical reason for there being three categories in that although monadic, dyadic and triadic nodes are irreducible, every node of a higher valency is reducible to a "compound of triadic relations".<ref>''Ibid.'' p.176</ref> [[Ferdinand de Saussure]], who was developing "semiology" in France just as Peirce was developing "semiotics" in the US, likened each term of a proposition to "the centre of a constellation, the point where other coordinate terms, the sum of which is indefinite, converge".<ref>Saussure F. de,''Course in General Linguistics'' 1916 (tr. Harris R., Duckworth, London, 1983) p.124</ref>