If I remember correctly, Kellhus understood how the Psukhe worked, that it was based on passion, simply by talking to Achamian about it on the road. How is it possible that Moënghus who went to Shimeh and worked with the Fanim could not understand how it worked before he agreed to have his eyes removed? Makes little sense for a Dunyain to agree to have his eyes plucked out so carelessly.