METAPHYSICS say truly ‘ ‘‘swims’’ is a verb’, but also ‘ ‘‘ ‘‘swims’’ ’’ is a noun’ That is the clue to understanding Frege’s claim that the concept horse is not a concept First, Second, and Third in Peirce In the English-speaking world, the most original system of metaphysics devised in the nineteenth century was that of C S Peirce It is true that Peirce’s principle of pragmatism resembles the verification principle of the logical positivists, and that from time to time he was willing to denounce metaphysics as ‘meaningless gibberish’; nonetheless, he himself constructed a system that was as abstruse and elaborate as anything to be found in the writings of German idealists Like Hegel, Pierce was fascinated by triads He wrote in The Monist in 1891: Three conceptions are perpetually turning up at every point in every theory of logic, and in the most rounded systems they occur in connection with one another They are conceptions so very broad and consequently indefinite that they are hard to seize and may be easily overlooked I call them the conceptions of First, Second, Third First is the conception of being or existing independent of anything else Second is the conception of being relative to, the conception of reaction with, something else Third is the conception of mediation, whereby a first and second are brought into relation (EWP 173) This triadic system was inspired by Peirce’s research into the logic of relations He classified predicates according to the number of items to which they relate ‘ is blue’ is a monadic or one-place predicate, ‘ is the son of ’, with two places, is dyadic, and ‘ gives to ’ is triadic A sense-impression of a quality is an example of a ‘firstness’, heredity is an example of a ‘secondness’ The third class of items can be exemplified by the relationship whereby a sign signifies (‘mediates’) an object to an interpreting mind Universal ideas are a paradigm case of thirdness, and so are laws of nature If a spark falls into a barrel of gunpowder (first) it causes an explosion (second) and does so according to a law that mediates between the two (third) Peirce was willing to apply this triadic classification very widely, to psychology and to biology as well as to physics and chemistry He even employed it on a cosmic scale: in one place he wrote ‘Mind is First, Matter 181