…an appreciation of the role played by the stam in the sugya, which is distinguishable from that typically played by amoraim. The stam often takes upon itself tasks that affect the sugya or sugyot as a whole…. The tasks of the amoraim, in contrast, are localized, consisting of the interpretation of a particular tradition, stating the law, resolving or posing an objection, or answering or raising a question. … It is the way of the stam to offer artificial responses, sometimes to teach us why a particular argument was chosen over another, sometimes to increase the complexity of the argument, and sometimes to weave together independent traditions or discussions.
Richard Kalmin, “The Function and Dating of the Stam and the Writing of History”, in Melekhet Mahshevet: Studies in the Redaction and Development of Talmudic Literature, ed. Aaron Amit and Aharon Shemesh (Ramat-Gan, Israel: Bar-Ilan University Press, 2011), 40-41 (English section).