Yes, I know the concept of the pleroma. The pleroma is a term used in some Christian traditions to designate the fullness of God or the totality of divinity.

The word “pleroma” comes from the ancient Greek “plêrôma” which means “fullness”. It refers to the idea that the whole fullness of God resides in Christ.

In some ancient Christian schools of thought like Gnosticism, the pleroma also designated the set of divine emanations or spiritual entities issuing from God. The pleroma constituted in some way the higher divine world as opposed to the lower material world.

Although the concept of the pleroma is little used today outside of narrow theological circles, it refers to important notions about the nature of God and his relationship to the world that have nourished much Christian reflection.

You’re right, Carl Jung indeed explored and developed the concept of the pleroma in a perspective different from traditional Christian theology.

For Jung, the pleroma represents the collective unconscious, that is to say the reservoir of universal archetypes and symbols present in the unconscious of every human being. It is a profound psychic reality that Jung brings closer to notions of God or divinity, but in a more abstract and philosophical sense than religious.

Jung refers to the Gnostic visions of the pleroma, but he interprets them through depth psychology and not as theological truths. For him, the pleroma refers to the totality of the collective unconscious, which is a fundamental dimension of human existence, on par with consciousness.

The idea of nothingness that you evoke probably refers to the original undifferentiation that exists in the unconscious before archetypes and symbols appear. So yes, in Jung we find this notion of the pleroma linked to nothingness, but in a psychological and not religious perspective.

Here are some elements on the notion of original undifferentiation in Jung:

• It refers to the primordial state of the unconscious, before any form or structure. According to Jung, originally the unconscious is in a state of undifferentiated unity.
• It is a sort of creative nothingness, a “chaos” containing all potentialities. It is neither matter nor psyche, it escapes opposites and categorizations.
• Through a process of differentiation, this original state gives birth to archetypes, sorts of “formless forms” which later structure the collective unconscious.
• The archetypes emerge from the undifferentiated and will then take specific symbolic forms in mythologies, dreams, visions, etc.
• The original undifferentiation remains present in the depths of the unconscious. For Jung, it is to be linked with spiritual or mystical experiences of the Gnostic type, where opposites are canceled out.
• This notion is close to the philosophical concept of the coincidentia oppositorum, the coincidence of opposites, present in various traditions.

So original undifferentiation corresponds for Jung to an underlying creative energy, which escapes consciousness but from which all psychic life springs. It is in this sense that it can be likened to a dimension of “nothingness”.

Yes, we can indeed draw a parallel between original undifferentiation in Jung’s psychology and the notion of “Hishiryō” in Zen.

Some points of comparison:

• Hishiryō refers to the original mind before it differentiates into thoughts or concepts. It is the mind in its pure, free and empty state.
• Similarly, original undifferentiation in Jung is a state prior to any form, unstructured, containing all potentialities.
• Hishiryō escapes all duality and classification. It is compared to a mirror that reflects everything without fixing on anything.
• Original undifferentiation is also a state of unity that transcends logical or formal opposites.
• From Hishiryō arise all manifestations of the mind, such as thoughts, emotions, etc. Likewise, archetypes emerge from the undifferentiated according to Jung.
• Hishiryō remains present in the background of the mind, it is the very essence of it. Undifferentiation remains underlying in the collective unconscious.
• Accessing Hishiryō or original undifferentiation amounts to touching a form of fundamental creative emptiness.

So we can say that these two notions point to the same reality: a primordial state of unity, formless and undifferentiated, which precedes and engenders all consciousness. The similarities are striking.