This inquiry capitalizes on the relational character of Peirce’s index. Its evolution from object finder in the physical world, to enhancer of communication between minds, to modal/perspectival coordinator is examined. Its relational character organizes events into episodes, and obviates perspectival alterations in dialogic reasoning. This shift demonstrates Peirce’s last word regarding Index: a sign intrinsically dialogic, whose interpretants increase levels of consciousness, and advance communicational interaction by commanding self/others to believe/act in novel ways. Its power to coordinate specific, vivid images provides index with the means to suggest novel propositions, assertions, and arguments. Peirce memorializes this relational role by characterizing index as Dicisign, and afterward as Pheme (1904, CP 8.334–8.339; 1906, MS 295: 26; 1908, EP 2: 489–490). As truncated Argument, Index provides the catalyst for interpreters to determine the meaning of interpretants be they Energetic, Logical or Final. Its non-symbolic character provides interpreters the impetus to utilize inferencing powers to attach meanings, thus expanding kinds of interpretants. Index constitutes the most diverse semiotic tool for interpreters – it traces subtle deontic, epistemic, and logical shifts. In situating and resituating events in time, place, and participatedness, Index aptly measures actual and potential shifts in affect, attention, location, credibility, and the like. Ultimately, index integrates the logical with the phenomenological and the empirical with the semiotic – when it deploys relational operators to trace event templates and to predict participant’s perspectives. As such, interpreters restructure thought and action and recommend sound courses of action for diverse event participants.