Making it all work - Berakhot (Blessings) 2b [or not 2b?]
In today's Talmud page, we see a good example. In 2a we heard how late one can recite the evening Shema; now the Talmud tries to determine when one may BEGIN reciting it. And so they consider many traditional sayings that all have different standards on the issue. Some of them are original to Talmudic rabbis, but some are "Baraitot" (sing. Baraita) - sayings from the time of the Mishnah that were not included in the Mishnah but are still authoritative because they are from that generation. If all are traditional, they should all (or at least most) agree on when one can begin. An analogy would be reading Thomas Jefferson's diary to get insight on the Constitution - the earlier Mishnaic rabbis are the"Founding Fathers" for the Talmud rabbis.
Thus we find a long discussion trying to prove that the time a poor man gets home is the same as when the priests would eat their terumah (holy food offered at the Jerusalem Temple). The fact that the Temple has been destroyed for centuries, and thus any descendants of the priests have no terumah to eat, is irrelevant to the discussion. And so one might ask, "how does this discussion help anyone who would want to know precisely when to recite the evening Shema?"
Just as this page offers two prooftexts (in case you don't like one) and claims that saying something happens at twilight can mean that it is BOTH day and night, there are two ways to consider this discussion. If one is looking for reasons, multiple ways of thinking about when to start give you many clues to look for - say, if you don't live near a priest or a poor man. Or one could just call it Pilpul - hairsplitting legal discussion for the sake of legal discussion. For these Rabbis, studying traditional teachings and trying to weave them together as part of a divinely-authored whole cloth of the "Oral Torah" was the most important mitzvah (commandment) to perform.
Today, we try to make our laws and legal discussions relate to the real world, but how many times have you yourself gotten caught up in arguing an unimportant detail for the sake of argument (and even enjoyed arguing for the sake of arguing)? So I can forgive the Talmud for this extended discussion on when night begins, and if I ever need to know what time evening begins there are plenty of more scientific resources to tell me when the sun sets - for that, the weatherman is actually useful. And I can live with contradictions in my traditions - if they were created by human beings, as I believe they were, then there will be disagreements and contradictions in them. As the old joke goes, "Person A is right, and person B is right." "They can't both be right!" "You are also right!"
Rabbi Adam Chalom