Well if a being is going on instinct or just mere hedonistic behavior then you can conclude that the choices that do not help them towards that hedonistic need he will avoid. 
And because of that it'll close his mind off of higher reasoning and other possibilities because it doesn't pertain to what he wants. Eliphas doesn't want to rule Kurn because he wants to make kurn better, he doesn't care about going against god and probably hasn't thought of the consequences of going against god. 

Thus he doesn't really... Think.. about things that won't benefit him. Basically what a wild animal does.