Authority is the backbone of law. Doesn’t U.S. law make sense (if at all) because of the authority granted to the Supreme Court, judicial precedents, the Constitution? Doesn’t the “rule of law” depend upon its well-ordered and predictable authorities? Authority in Jewish law, not unlike secular law, seems to be grounded on a series of hierarchical principles. Such principles portray halakhah as an orderly system of law. Therefore, we might expect our daf yomi readings of the Talmud to show the inner-workings of this orderly system. Indeed, in tracing the (wandering-Jew-ish) argumentation, we see many signs of this orderly picture.
Nevertheless, every page of Talmud also testifies to a less-hierarchical nature of halakhah and the rather chaotic, non-systematic quality of halakhic authority. Through this post, I hope to start illustrating how Talmudic discourse itself calls into question some oft-rehearsed principles of halakhic authority. Caveats: (1) Experienced readers of halakhah will find these points rather mundane. (2) I’ll be making mistakes and would appreciate corrections.
Principle: The Tannaim and their statements are authoritative for the Amoraim.
As is well known, if Rav disagrees with a Tanna, then the Rishonim sometimes treat Rav with the authority of a Tanna. So Rav becomes a borderline tanna/amora. (Rashi lo d’gamar makah, Shab 53b)
Shmuel also seems to override Tannaim on occasion. To keep him within the hierarchy, Rishonim must assume that Shmuel had an unidentified tannaitic tradition (70b, Tosafot lo mashma leh)
It is clear that the Amoraim are in charge because they can reinterpret the Tannaim to satisfy the Amoraic view. For instance, amoraim adjust the “plain” meaning or application of a tannaitic statement. More blatant reinterpretations may (i) claim that the tannaitic text is defective (37a, 62b), or (ii) attribute a tanna qamma (the anonymous opinion of a mishna or baraita, which is presumed to be the majority) to a single, minority opinion. In such ways, the Talmud is implicitly shifting to a post-tannaitic authority.
At times, it is explicit that the Amora is authoritative. For instance, R. Zeira revises a reading of a mishnah “so as not to break the opinion of R. Yochanan.” (46a)
Sub-principle: While the tannaim are theoretically more authoritative, the interpretations of the amoraim are what counts in deciding halakhah. (E.g., last Rashi, Niddah 7b) So the authority of a foundational document -- whether Mishnah or the U.S. Constitution -- is necessarily subordinated to legal hermeneutics.
Principle: The halakhah follows the majority of the sages (as stated, e.g., 60b)
But the halakhah may be decided in line with a minority opinion. E.g., Chananiah (Shab ch 3, 36-37).
The Talmud also approves a minority view when there may be a physical or monetary loss with the majority ruling. For example, in dealing with the Chanukah lights, R. Shimon can be relied upon at urgent times (b’sh’at ha-dekhaq) (45a)
Sub-principle: An individual may be allowed to follow a minority approach (e.g., Beit Shammai) if it’s done consistently. In other words, no shopping around for leniencies by picking and choosing one’s authorities. However, R. Ami objects that R. Nachman at one point is following 2 different teachers, as if by personal preference. (51a)
Today: On some questions, it’s hard or impossible to discern a majority. Although some Jews follow a specific Rav, others do not follow a consistent line of authorities. So, a poseq (rabbinic decisor) may cite Maimonides in one ruling and oppose him in the next.
Well, this is a work in process and your input is most welcome as I revise this.
 Literary sources of law mostly can be ranked chronologically. Scripture is more authoritative than rabbinic literature. Within Tanakh, the Torah (Pentateuch) outranks the Prophets and Writings. Within the Talmudic corpus, a mishnah > a baraita (non-mishnaic tannaitic statement), mishna > gemara, the Babylonian Talmud > the Yerushalmi, etc. By the same token, the ordering of sources matches the ranking of human authorities. So, Moses has attributed oral rulings (halakhah le-Moshe mi-Sinai, e.g. Shab 62a) that trump those of the rabbis. The sages of the Mishnah (the Tannaim) are authoritative for the rabbis of the Talmud (the Amoraim). Similarly, the earlier post-talmudic halakhic leaders (the Geonim and the Rishonim) are considered authoritative for the later Akhronim. On the other hand, there is a post-talmudic principle that the contemporary generation in practice needs to set the halakhah for its own time: "the law accords with the later rabbis" (hilkheta ke-vatrai'ei).
For each source and generation of human authorities, moreover, there are formal rules to govern halakhic decision-making. Notably, disagreements among rabbis are to be settled in line with the majority. Specific guidelines show how the majority opinion may be identified (e.g., when the school of Hillel prevails over Shammai, Rav over Shmuel, Rava over Abaye, and so on).