It must be reckoned a psychic catastrophe when the ego is assimilated by the self. The image of wholeness then remains in the unconscious, so that on the one hand it shares the archaic nature of the unconscious and on the other finds itself in the psychically relative space-time continuum that is characteristic of the unconscious as such.4 Both these qualities are numinous and hence have an unlimited determining effect on ego-consciousness, which is differentiated, i. e., separated, from the unconscious and moreover exists in an absolute space and an absolute time. It is a vital necessity that this should be so. If, therefore, the ego falls for any length of time under the control of an unconscious factor, its adaptation is disturbed and the way opened for all sorts of possible accidents.
— Carl Gustav Jung
Jung's word "catastrophe" is doing something precise here that spiritual culture routinely softens into invitation. The absorption of the ego by the Self is not enlightenment; it is a structural failure of the psyche's ability to navigate actual time and actual space. What he is describing — the image of wholeness remaining unconscious while flooding consciousness with numinosity — is the mechanism underneath every experience of inflation that arrives wearing the face of awakening.
The numinous, by definition, overwhelms discrimination. That is its nature and its danger in the same breath. An ego that has been swallowed by the Self does not experience itself as swallowed; it experiences itself as arrived, as finally sufficient, as no longer subject to the ordinary grinding conditions of embodied life. And that is precisely where adaptation breaks down — not in the dramatic failures, but in the quiet abdication of the differentiated, temporally-located self that is capable of actually meeting what happens.
Wholeness, as Jung insists here, must remain an image held at some functional distance. The work is not to become it but to stay in relation to it — which requires an ego intact enough to bear the tension rather than dissolve into the relief of merger.
Carl Gustav Jung·Aion: Researches into the Phenomenology of the Self·1951