People are souls, not selves. But to figure out what one's soul connections are and what they ought to be  is hard.

Isaac Luria goes into this in some depth but the short of it in a practical sense is there is a certain amount of control a person has over what he feeds his mind. And what he absorbs into his mind at first is software but after some time becomes hardwired. Howard Bloom went into this in detail and I can't repeat the whole thing here,[ in The Lucifer Principle].

In any case this is certainly an argument for Musar [the books of Ethics from the Middle Ages plus the books that came out of the Musar Movement.]

But my point is a little more subtle. First that one can not always tell why or from where his or her attraction to a certain group comes from. It might be from the Realm of Holiness, or t might be from the Sitra Achra [the Dark Side]. An the fact that it is intense and feels great is no proof one way of the other.  

But the Rambam does give a pretty decent way of discerning--Reason. Natural Law was a level that was needed before the giving of the Torah. And though natural law  needed to be revealed to Abraham, still once it has been revealed already to human consciousness, it provided a base upon which Matan Torah could happen.  [This also goes along with the idea of certain periods in history being unique and prepared for certain kinds of Revelation.]\

In any case we can learn from this the importance of Musar and learning Torah.