The Rabbis have contended points of Law for centuries. Many people have the impression that the in Talmudic discussions, Laws have been changed countless times. That being the case, why can’t we do the same?
There are really two issues here: the nature of the Rabbinical debates, and our authority to decide Jewish Law. We’ll begin with the first point.
Yes, the Rabbis have contended points of Law, but always on minor details of Laws, never on major issues. Nowhere in the Talmud will you find differences on core matters. If you think you know of any, please cite them to me.
Secondly, each and every disagreement in the Talmud is based on strict and unalterable rules and parameters. Each and every point of view is based on the application of specific established relevant and correct rules in each case.
Thirdly, no one voiced personal opinions based on their emotions and «what feels right.» They based everything on established Halachic precedent.
When, for example, Bais Shammai (the School of Shammai) and Bais Hillel (the School of Hillel) disagree about the lighting of Chanukah lights, it is never about the basic, major concepts of Chanukah that they disagree.
All agree that each household is required to light one light per night for eight nights.
All agree that a higher level is to light one light per person each night.
All agree that the highest level — admirable, but not obligatory — is to vary the number of lights each night.
The problem was that in those days no one could afford to light more than one light per night, so the practice of multiple lights had fallen into disuse. What then was the original Law ordained by the Rabbis two centuries earlier?
Thus, what they differ on is whether to increase the lights or to decrease the lights. Each has a logical theory based on established Talmudic concepts that were applied to other Laws.
Bais Shammai says it should resemble the Biblical Commandments of the Sacrificial offerings of the Succos Holiday, since the Rabbis usually instituted details of Laws in forms that resembled Biblical Law. Since those sacrifices decreased in number, so should the Chanukah lights. We should therefore start with eight and decrease until one.
On the other hand, says Bais Hillel, we have a rule that in holy matters we increase, not decrease. In keeping with this standard, we should start with one light and increase each day.
That is how a disagreement takes place in the Talmud: only on a minor matter, and only between very learned scholars who had good Talmudic reasons for expounding a theory.
The fact that such people can disagree does not give license for the likes of us to abrogate any Law of the Torah because we feel we have the right to disagree.
So it is not correct to say that «Since the Rabbis disagreed, so may we.» Even the Rabbis were cautious before they disagreed with another Rabbi, how much more so must we!