ושני לאמים ממעיך יפרדו
And two nations from your bowels (womb) will diverge...
Rashi explains: From your bowels (womb) they will be divergent; this one (Eisav) toward his wickedness and this one (Yaakov) toward his completeness.
Yaakov and Eisav were two very different characters and, as Rashi tells us, they were very different from the moment of conception.
But, what Rashi says to us seems to be going "against our grain". He indicates that Eisav was "born" to be wicked. As if it was pre-destined. And likewise, Yaakov was "born" to be righteous.
How do we reconcile this with our philosophy of "bechira"? Was Iyov right that every person's lot is dictated by his astronomical fortunes?
I don't think so. And I don't think this is what Rashi means either. Although Eisav could never be like Yaakov, I think he was very similar to Aharon HaCohen. And he could have been Aharon HaCohen. And he was meant to be Aharon HaCohen - the older brother who does the avoda while the younger brother (Moshe Rabenu/Yaakov) teaches the Torah.
He just passed up the chance.
To help us understand this, it may pay to do a little psychological analysis on the "divergence" between Yaakov and Eisav based on the principles of Carl Jung. And that's exactly what I did in a term paper about five years ago.
So, for all you Myers-Briggs buffs out there, I present:
Torah Perspective on MBTI Typology