Class Forty Two in Section Four of Neshamos come

Neshamos are connected to Keilim (thought) (16). The “limitation” of Keilim and Neshamos of Keser is that they are “only” like שם התואר and not like שם העצם. They don’t allow access to the אור of whatever כח without a hold from the כלי which is separate from the עצמיות האור. Thus in Kesser the Keilim (and Neshamos) are very unified with אור but still with some הבדלה התחלקות.