to bring up the obvious, the fifth part is "Regard du Fils sur le Fils", which means the infant is part of the consciousness partaking of the contemplation, but just a part. the contemplating subject can be described as a universal spirit, encompassing and transcending all parts of the xystyin trilogy, and not confined to a particular moment of conventional time, either, because the infant's mortal future is foreseen in part seven, non-finite time referred to in parts nine and seventeen. and there's another Messaien composition that refers to the end of time, indicating he meditated on the metaphysics constantly with his musik.