There is actually a pretty cool place Scripture speaks on this, at least the two ‘forms/traditions’:
Acts 23:8 The Sadducees say that there is no resurrection, and that there are neither angels nor spirits, but the Pharisees acknowledge them all.
These are probably not the only differences, but some significant ones. How the Sadducees denied angles has always been a question I’ve had, especially since Genesis and such clearly mention them. Or were the Sadducees some sort of ‘liberal’ group that considered that stuff non-literal?
Not really. The Sadducees, surprisingly, were THE conservatives when it came to matters of religion.
The Pharisees were politically conservative while being religiously liberal - they allowed for new ways and developments in Jewish thinking, trying to find ways in which Judaism can still survive and be ‘relevant’ in the changing world (adapting traditional Jewish life to new circumstances), welcoming ideas which came into fruition only in the post-exilic period such as the resurrection of the dead. The Pharisees stood for a post-prophetic idea of Judaism: emphasizing the synagogues more than the Temple, the rabbi (and the average layman) more than the priests, and prayer more than the sacrifices. This flexibility is probably what helped the Pharisaic beliefs survive the times and turn into the present rabbinic Judaism.
The politically liberal Sadducees, meanwhile, were actually religiously conservative and traditional to the point of being fundamentalistic - this is to be expected, as upper classes in many traditional societies tended to have a ‘conservative reflex’, and many, if not most of the upper classes in Jewish society, such as the Jewish priesthood and the aristocrats, belonged to the group.
They held an ancient, pre-Prophetic form of Judaism as held and transmitted by the hereditary priesthood which as mentioned centered itself on the Tabernacle/Temple, the
kohanim (priests), and the
korbanot (sacrifices), and insisted on a very strict, literalistic, by-the-letter interpretation of the Torah - that Josephus once called them “
heartless” than any other Jews “
when they sit in judgment”. All laws and doctrines must have a basis in the Torah; if they can’t see them there, ta-ta.
IMHO, they seem to have regarded things as being set in stone and criticized any ‘newfangled’ ideas/interpretations which do not agree with theirs, as they did to the Pharisees for their ideas of say, the resurrection or the ‘Oral Torah’, and their holding tradition to be a living, continuing process. In fact, it is even said that they opposed any attempted reforms in the sacrificial functions of the Temple!
Their placing great importance on the Temple and its priesthood were such that they were willing to collaborate with whoever had the upper hand at the time - maybe it was all in the name of preserving the Temple’s cult and keeping the
status quo which has them at the top. It was also probably one of the reasons as to why the Sadducees became virtually extinct after the destruction of Jerusalem in 70 AD.