This reminded me of the summary of Prof. Michael S. Berger's excellent book - Rabbinical Authority. He says that determining the source of Rabbinic authority in the traditional world is basically a description of what a particular community considers to be authoritative. On the other hand the more modern elements say that we need to identity objective sources of authority - which are independent of what people in a particular community do.
p154-155
"Interpreting legal texts led us in chapter 9 to introduce Stanley Fish's analysis of literary criticism, which situates all interpretation within the context of interpretive communities. Indeed, a "text" has no existence independent of such a community, for only a community, with its values, assumptions, principles, etc., may construe a text as a "text" in the first place. We teased out the implications of such a model for interpretation in legal traditions in general and in the Jewish legal tradition in particular, showing how the ways the Sages read the Torah became characteristic of that community and were subsequently (consequently?) applied to the Mishnah, the Talmud, and even medieval codes.
All three chapters of part III offered alternative understandings of authority that, to varying degrees, rejected the Enlightenment assessment of authority. The Enlightenmentent model demands that some justification be provided for forgoing one's own independent judgments and decisions in order to defer to another's view. But in part III I tried to show that authority is embedded in a form of life which, in the end, renders such rational justification beside the point. Applying a Wittgensteinian approach to the issue of Rabbinic authority, we saw that the issue could not truly be understood outside a set of circumstances that already situates it - and those subject to it - in a particular context. Description, rather than justification, was seen to be a helpful and productive way of analyzing authority. The question that came up in the nineteenth century and that continues to the present is not really about the authority of the talmudic Sages but is about the contemporary relevance or appropriateness of a form of life that makes the Sages of late antiquity central to one's entire outlook and set of concerns. Various interpretive communities, represented in part by the range of Jewish denominations today, have resolved this issue in a variety of ways, and each, in the end, construes the "text of the Talmud" and "Rabbinic authority" quite differently. The choices made by each community naturally bear consequences for its members, but it is only in terms of these interpretive communities that we can properly discuss the issue of the Talmud's, or Rabbinic, authority.
No simple solutions, therefore, await us as we inquire into the nature of Rabbinic authority. Sages, texts, and interpretive communities and forms of life mix inextricably in complex and subtle ways such that the effort to separate them and view one as antecedent or primary to the others fails to capture how authority is to be understood in Judaism. Rabbinic authority is necessarily conceived in the intricate interface of community and text, a fitting condition for "the people of the Book."