86 Peter Knobel

detail the right of sages to amend or abrogate norms that are considered de-oraita(toraitic). The authority of the decisor is extensive: in the most extreme instance, the principle pe’amim she bitulah shel Torah zehu yesodah— sometimes the abrogation of Torah , which is its foundation. When the ultimate goals of the Torah would be better served by its abrogation, even in its entirety, it is within the purview of the sages to take that step. The circumstances that might warrant such action are never defined. In the final analysis, the determination of the need for such action lies with the sages themselves. As Moses rendered the decision on his own.

23 so too must the sages make the decision on their own

The Sages used medical and scientific sources to change the law.

What counts is the specialist’s expertise. [t is a matter of record that the number of matters of law in the first sense stipulated in the talmudic sources and contradicted either by the expert scientific opinion of later ages or by the personal observation of later sages has produced many problems. How could it be that the talmudic sages had been mistaken? Surely it was not reasonable to suppose that the talmudic sages had misperceived their own reality. It was more reasonable to surmise that the reality had changed and once it became acceptable to make such a claim, medical/scientific sources that might result in the abrogation of previously held legal norms could be introduced without impugning the reliability or integrity of the talmudic sages. A new systemic principle referred to as shinnui ha-itim— change reality— became the vehicle that enabled later sages to make use of new medical/scientific knowledge without vitiating the smooth functioning of the halakhic system.** Roth further writes: [fnew medical/scientific evidence indicates that a norm no longer applies to a majority of cases, and the norm itself was ground in earlier medical/scientific evidence that it did apply to a majority of cases, the extralegal sources allow the reopening of the question of the factual basis upon which the norm was predicated. In such a case, the extralegal sources allow the norm to be overturned by the claim of shinnui ha-itim if the evidence is strong enough?

New information can also alter the meaning of a text. Archaeological, historical, and philological research is utilized to

analyze a text. Such an analysis can potentially reveal that the text has