Definitions of concepts in learning

I study rabbinical law (specifically now prohibition and permission), and I often encounter situations with undefined concepts.
These are usually concepts for which there are several extremes, and the former attempt to reconcile and divide between cases in a very technical manner, but without clearly defining the concept so that it will reconcile with all cases.
The current example I encountered is the issue of "creation" where it seems that Rashi and the Rabbis confuse the concept of creation with its practical implications regarding eating a forbidden food (so they write that a prohibition that was not created at the time of the creation of the reptile/animal does not have the law of creation).
This is a rather long introduction, but my question is more general and fundamental,
1. Where are there Halacha textbooks that care about trying to understand the principles and not just what everyone says (because studying this way is pretty much like memorizing exercises for a test instead of learning the formulas)?
2. If I find a connecting principle and define the concept, does that have any meaning, or did the early ones (and the Amoraim themselves, etc.) not work logically and did not define concepts but rather divided them in a more technical way (I am generalizing, of course)?
3. If the answer to question 2 is that there is not necessarily a clear principle, is there any meaning to my study when in practice I have no way of applying it too much to practical questions (because a pure bird is alive, I probably won't be eating it anytime soon)?
Apologies for the length.
Thank you very much.