Losing the will to believe (part 1)

For me, leaving religion was a result of ceasing to believe in the fundamental tenets of Judaism. And, this loss of belief preceded changes in my day-to-day practice and adherence to Jewish law.

My loss of belief came in phases. First, thinking about day-to-day practice led me to wonder about the authority conferred on Rabbis to determine the proper interpretation of the law, for instance:

1) Even if one were to accept that God gave the Torah to Moses at Sinai (and delivered along with it a set of oral law), why think that the Rabbis who codified the mishnah and the Talmud correctly resolved uncertainties about what the oral law is. That is, why think that the Talmud made no mistakes about the law God was purported to have given to Moses at Sinai?

2) Even if one assumed that the Talmud correctlycaptured the oral law, why think that the early commentators on the Talmud (the rishonim, e.g., Maimonides) knew better how to resolve uncertainties in the talmud than later commentators.

3) Why assume that the shulchan aruch, a 16th century codification of Jewish law that is generally considered doctrine in orthodox communities correctly resolved the uncertainties it addressed about what was the proper interpretation of Jewish law?

Faith in God was one thing; blind deference to learned Rabbis (however learned and wise, but still, of course, human and fallible) was another.