The Rabbinical sources on this subject are of the highest importance; a detailed examination of them would require a special volume, but much valuable information has been gathered by Hölscher[176] and, in greater abundance, by Leszynsky.[177] Though the evidence is of a complicated character it fully bears out that of Josephus on this point. The Sadducees stood for the written Law, and this only; the Pharisees insisted upon the binding authority of the tradition of the fathers as well. That is the fundamental difference between them; the developments which either party saw itself compelled to countenance arose logically and irresistibly from this fundamental principle regarding the Law. But these developments were profoundly important. We will put the matter as succinctly as possible. The Sadducees stood for the written Law; but in the nature of things it constantly happened that new cases came up for decision for which the written Law provided no solution or guidance. The Sadducees were thus forced to put forth new ordinances; and in this they followed, _nolens volens_, the example of the Pharisees[178]; but, true to their fundamental principle, they saw to it that these new ordinances were based upon the written Law, so that they could claim that if changed conditions of life, or whatever other cause, necessitated the putting forth of new legal ordinances, these were at any rate developments of the written Law.[179] With the Pharisees it was different; they had always, in addition to the Law, championed the traditions of the fathers, i.e. the popular customs handed down from time immemorial; these had constantly been added to, whether based upon the written Law or not. From the point of view of loyalty to the Law the Sadducæan position was unassailable, while that of the Pharisees was open to objection. The result was an intensive study of the letter of the Law (i.e. the Pentateuch), both by Pharisees and Sadducees; the former undertook this in order, by a method of interpretation peculiarly Pharisaic, to prove that the oral tradition was based on the written Law. They were forced to this by the more strictly legal attitude of the Sadducees; these latter, too, gave themselves to the minute study of the Pentateuch as never before, because, as the true guardians of the Law, they had to see whether in each individual case the Pharisaic contention was justified that such and such an ordinance of the oral tradition was based upon the written Law.