fact that a person is aware of the actual possibility of exercising a choice and sometimes the fact that he chooses are popular meanings of rationality" Grounds of choice: "The grounds upon which a person exercises a choice among alternatives as well as the grounds he uses to legitimize a choice are frequently pointed out as rational features of an action" Compatibility of ends-means relationships with principles of formal logic: "A person may treat a contemplated course of action as an arrangement of steps in the solution of a problem" Semantic clarity and distinctness: "Reference is often made to a person's attempt to treat the semantic clarity of a construction as a variable with a maximum value which must be approximated as a required step in solving the problem of constructing a credible definition of a situation" Clarity and distinctness "for its own sake.": "Schütz points out that a concern for clarity and distinctness may be a concern for distinctness that is adequate for the person's purposes." Compatibility of the definition of a situation with scientific knowledge: "A person can allow what he treats as 'matters of fact' to be criticized in terms of their compatibility with the body of scientific findings" Garfinkel notes that often, rationality refers to "the person's feelings that accompany his conduct, e.g. "affective neutrality," "unemotional," "detached," "disinterested," and "impersonal." For the theoretical tasks of this paper, however, the fact that a person may attend his environment with such feelings is uninteresting. It is of interest, however, that a person uses his feelings about his environment to recommend the sensible character of the thing he is talking about or the warrant of a finding." Reflexivity Reflexivity means that members shape action in relation to context while the context itself is constantly being redefined through action. Garfinkel regarded indexical expressions as key phenomena. Words like here, now, and me shift their meaning depending on when and where they are used. Philosophers and linguists refer to such terms as indexicals because they point into (index) the situational context in which they are produced. One of Garfinkel's contributions was to note that such expressions go beyond "here", "now," etc. and encompass any and all utterances that members of society produce. As Garfinkel specified, "The demonstrably rational properties of indexical expressions and indexical actions [are] an ongoing achievement of the organized activities of everyday life". The pervasiveness of indexical expressions