This essay, though published in 1978, was an expansion of a chapter in my Master’s thesis, submitted over a decade earlier. Being my earliest venture in writing the history of halakhah, it set forth my approach to the subject, not abstractly but concretely— in the form of explication de texte. The step-by-step interrogation of the sources yielded what to my mind were the building blocks of the narrative. The data and the modes of inference were thus opened to scrutiny, and the reader could judge for himself the validity of the conclusions. The same techniques of the textual edition, locating doctrines in their contemporary context and searching for personal posture and external influences by the criterion of ‘measurable deflection’, have been employed in all my subsequent studies; however, they are never so clearly placed on view as in this essay.

This essay and the preceding one on pawnbroking are studies in detailed reconstruction, and certain patterns emerge. Here too, Rabbenu Tam, alongside Rashi, plays the major role. Indeed, Rabbenu Tam's doctrines dominate the entire field of yein nesekh. The leading part he played in shifting halakhah from exegesis to dialectic is common knowledge. Less well known is the fact that this profound involvement in dialectic was coupled with a keen instinct as to when this newly revived method would be of no avail. He intuitively rejected, as we shall see, all distinctions between gat and gigit as being unpersuasive—as, indeed, the belabored efforts of his successors proved them to be. On another occasion, he swiftly and emphatically stated that dialectics would prove incapable of justifying the widespread practice of accepting Gentile wine (setam yeinam) in payment of debts, something that took his disciples anywhere from two to five generations to realize.

The space devoted to Rashi and his predecessors takes up some 60 percent of both studies and for the same good reasons. The views of Early Ashkenaz on yein nesekh must be teased out of the sources, and the quiet but transformational role of Rashi comes repeatedly into view—once his words are closely interrogated. In this essay, as in the preceding one on ribbit, Rashi is in constant dialogue with his predecessors and contemporaries and, equally, with his religious traditions, with all their stringencies, leniencies, and taboos. We witness in both studies Rashi's growing confidence and his gradual willingness to take issue with established practice.