hree modes of inference ... Abduction, or the suggestion of
     | an explanatory theory, is inference though an Icon, and is
     | thus connected with Firstness;  Induction, or trying how
     | things will act, is inference through an Index, and is
     | thus connected with Secondness;  Deduction, or
     | recognition of the relations of general ideas,
     | is inference through a Symbol, and is thus
     | connected with Thirdness.

DL:  This, it seems to me, reaffirms his opinion of 1867 (CP 1.559):