The passage, famous passage in Antiquities (book) 18, that describes the four schools or philosophies of Judea—the Pharisees, the Sadducees, Essenes, and an unnamed fourth philosophy—they provide a good example of misreading Josephus; that is, I’ve just said it’s important to read him but the problem is that if you read him superficially and take him simply at face value, you misunderstand what’s going on in the text. This is an intelligent author and not a mine of data that you can simply reach into and pull out what you need for thinking about the New Testament, for example.
So, in this case, in four other passages, Josephus tells us that there are three philosophies, the Pharisees, Sadducees, and Essenes and only three and he’s consistent about this all the way through his writing.
Many people think that because of these three, members of the Pharisees, Sadducees, and Essenes would recognize each other as one of the three philosophies; and they even think that there was such a thing as a fourth philosophy whose members in the marketplace would recognize each other—“you belong to the fourth philosophy the way I do.”
Well, I would like to say that this is a complete literary invention of Josephus, on the spot, in Antiquities 18 and it has to do with what he’s writing about there. So he mentions a fellow named Judas of Galilee and says he introduced a novel philosophy, namely one of rebellion against leaders so this has nothing to do with traditional Judean life.
He goes into the others, he says we only have three philosophies and he says, well this was like a fourth philosophy and it’s really intrusive and it’s not part of our tradition; so clearly he’s just inventing that for his literary purposes. He only thinks there are three and even those three are not something that is simply real life. If you asked a Greek how many philosophical schools are there, they would vary in their answers. Some would say two, maybe stoics and Epicureans; some would say ten and include the Pythagoreans and academicians and so on, cynics. It’s up to the individual person and Josephus chooses three and sticks with three, but that doesn’t mean we should think that there were three such things called philosophies in ancient Judea.