Origins of Judaism
For centuries, the traditional understanding has been that Judaism came before Christianity and that Christianity separated from Judaism some time after the destruction of the Second Temple in 70 CE. Starting in the latter half of the 20th century, some scholars have begun to argue that the historical picture is quite a bit more complicated than that. In the 1st century, many Jewish sects existed in competition with each other, see Second Temple Judaism. The sects which eventually became Rabbinic Judaism and Early Christianity were but two of these. Some scholars have begun to propose a model which envisions a twin birth of Christianity and Judaism rather than a separation of the former from the latter. For example, Robert Goldenberg (2002) asserts that it is increasingly accepted among scholars that "at the end of the 1st century CE there were not yet two separate religions called "Judaism" and "Christianity"".
Daniel Boyarin (2002) proposes a revised understanding of the interactions between nascent Christianity and nascent Rabbinical Judaism in Late Antiquity which views the two religions as intensely and complexly intertwined throughout this period.
Pharisees
During the Second Temple era, when Jews were divided into sects, the Pharisees were one sect among many, and partisan. Each sect claimed a monopoly on the truth, and discouraged marriage between members of different sects. Members of different sects did, however, argue with one another over the correctness of their respective interpretations, although there is no significant, reliable record of such debates between sects. After the destruction of the Second Temple, these sectarian divisions ended. The Rabbis avoided the term "Pharisee," perhaps because it was a term more often used by non-Pharisees, but also because the term was explicitly sectarian. The Rabbis claimed leadership over all Jews, and added to the Amidah the "birkat haMinim", a prayer which in part exclaims, "Praised are You O Lord, who breaks enemies and defeats the wicked," and which is understood as a rejection of sectarians and sectarianism. This shift by no means resolved conflicts over the interpretation of the Torah; rather, it relocated debates between sects to debates within Rabbinic Judaism. The Pharisaic commitment to scholarly debate as a value in and of itself, rather than merely a byproduct of sectarianism, emerged as a defining feature of Rabbinic Judaism.