Peirce's 1885 “Algebra of Logic” • Selection 1.2
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https://inquiryintoinquiry.com/2024/03/24/peirces-1885-algebra-of-logic-sel…
❝On the Algebra of Logic❞
❝A Contribution to the Philosophy of Notation❞
❝§1. Three Kinds Of Signs❞ (cont.)
❝But if the triple relation between the sign, its object,
and the mind, is degenerate, then of the three pairs
sign object
sign mind
object mind
❝two at least are in dual relations which constitute the
triple relation. One of the connected pairs must consist
of the sign and its object, for if the sign were not related
to its object except by the mind thinking of them separately,
it would not fulfill the function of a sign at all. Supposing,
then, the relation of the sign to its object does not lie in
a mental association, there must be a direct dual relation of
the sign to its object independent of the mind using the sign.
❝In the second of the three cases just spoken of, this dual
relation is not degenerate, and the sign signifies its object
solely by virtue of being really connected with it. Of this
nature are all natural signs and physical symptoms. I call
such a sign an “index”, a pointing finger being the type of
this class.
❝The index asserts nothing; it only says “There!” It takes hold
of our eyes, as it were, and forcibly directs them to a particular
object, and there it stops. Demonstrative and relative pronouns are
nearly pure indices, because they denote things without describing
them; so are the letters on a geometrical diagram, and the subscript
numbers which in algebra distinguish one value from another without
saying what those values are.❞
Regards,
Jon
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