 tested against
     the external is first, precision, then dissociation, then
     discrimination (e.g., MS 645).  These stages, Peirce says,
     take place before phenomenological enquiry, but if we were
     to apply the categories to these prephenomenological, or perhaps
     I should say 'mathematical' stages, I think precision would have
     the assurance of an icon, dissociation the assurance of an index,
     and discrimination the assurance of a symbol.  Note, however, that
     the inductive sta