What method(s) of reasoning did Abraham use to discover HaShem's existence and that he is Adon Olam? I'm wondering about particular methods.
[1] http://www.chabad.org/library/article_cdo/aid/434682/jewish/The-Abraham-Principle.htm [2] http://www.chabad.org/parshah/article_cdo/aid/2612/jewish/The-History-of-Monotheism.htm