Question

Hello Rabbi,
I can’t understand how any person, whether or not he is a rabbi, can derive a halakhic ruling from the Talmud. I have two problems with this.
The first problem is conceptual. As I understand it, the Talmud is a sequence of statements from the study hall that were written down on the page. If so, it could be that each amora had his own explanation of all the mishnayot, but the Talmud itself is certainly not coherent with itself. That is, the only way to derive Jewish law from the Talmud cannot be by ruling each time like a different amora, because then the Jewish law might contradict itself.
And the second problem is a practical one. When a person issues a halakhic ruling, he does not have a source sheet telling him from which Talmudic passages he should derive the ruling. In other words, a person would have to know the entire Talmud by heart and then go through all the topics in his head and think which passages are connected to the law he wants to determine. Practically speaking, that seems impossible. An ordinary person certainly can’t do that, and one would have to be a genius on an extreme level, with a great deal of time to sit and learn, in order to produce such laws.
Even so, it seems that many people rely on rabbis like the Shulchan Arukh or Maimonides for their halakhic determinations, without any real basis for knowing whether there are Talmudic passages they may have mistakenly omitted.
 
Wouldn’t it make more sense to say that the Talmud does not fit together with itself, and each Talmudic passage stands on its own? According to that, of course, when a person comes to derive a practical ruling for himself from a certain Talmudic passage, it may not fit with another Talmudic passage, but at least he would have a ruling in hand and not a major concern that perhaps he forgot to take some passage into account.