Here, for want of a demonstrable cause, we are all too likely to fall into the temptation of positing a transcendental one. But a “cause” can only be a demonstrable quantity. A “transcendental cause” is a contradiction in terms (p. 30, bold emphasis added).

[Note: Although items 5 to 7 are conditions for synchronicity, not strictly definitions, they play a central role in Jung’s interpretation of the phenomenon.]

In view of the possibility that synchronicity is not only a psychophysical phenomenon but might also occur without the participation of the human psyche, I should like to point out that in this case we should have to speak not of meaning but of equivalence or conformity (footnote, p. 86, bold emphasis added).

The synchronicity principle possesses properties that may help to clear up the body-soul problem. Above all it is the fact of causeless order, or rather, of meaningful orderedness, that may throw light on psychophysical parallelism. The “absolute knowledge” which is characteristic of synchronistic phenomena, a knowledge not mediated by the sense organs, supports the hypothesis of a self-subsistent meaning, or even expresses its existence. Such a form of existence can only be transcendental, since, as the knowledge of future or spatially distant events shows, it is contained in a psychically relative space and time, that is to say in an irrepresentable space-time continuum [transcendental idealism](pp. 89-90).

“Synchronicity” [is an] “inconstant connection through contingence, equivalence and meaning,” the fourth component of the universal quarternio of “indestructible energy,” “space-time continuum,” and “causality,” “constant connection through effect” (p. 98).

Into this category come all “acts of creation,” a priori factors such as the properties of natural numbers, the discontinuities of modern physics, etc. Consequently, we would have to include constant and experimentally reproducible phenomena within the scope of our expanded concept, though this does not seem to accord with the nature of the phenomena included in synchronicity narrowly understood. The latter are mostly individual cases which cannot be repeated experimentally. . . .

Our narrower conception of synchronicity is probably too narrow and really needs expanding. I incline in fact to the view that synchronicity in the narrow sense is only a particular instance of general acausal orderedness. . . . But as soon as [the observer] perceives the archetypal background he is tempted to trace the mutual assimilation of independent psychic and physical processes back to a (causal) effect of the archetype, and thus to overlook the fact that they are merely contingent. This danger is avoided if one regards synchronicity as a special instance of general acausal orderedness. . . . The archetype is the introspectively recognizable form of a priori psychic orderedness (p. 100).

[Note: Jung here defines “narrow synchronicity” as “equivalence of psychic and physical processes,” and “wider” or “expanded” synchronicity as “general acausal orderedness,” which is the objective (a priori) arrangement of deeper psychoid archetypes. Thus, “narrow synchronicity” (coincidence of psychic and physical events) is the explicit, detectable, unfolding of deeper, implicit, and unknowable, archetypal “acausal orderedness.” Jung’s archetypal domain of acausal orderedness differs, therefore, from Bohm’s implicate order which is causal.]

2. The coincidence of a psychic state with a corresponding (more or less simultaneous) external event taking place outside the observer’s field of perception, i.e. at a distance, and only verifiable afterward.

3. The coincidence of a psychic state with a corresponding not yet existent future event that is distant in time and can likewise only be verified afterward.

In groups 2 and 3 the coinciding events are not yet present in the observer’s field of perception, but have been anticipated in time in so far as they can only be verified afterward. For this reason I call such events synchronistic, which is not to be confused with synchronous (p. 110, bold emphasis added).

The term explains nothing, it simply formulates the occurrence of meaningful coincidences which, in themselves, are chance happenings, but are so improbable that we must assume them to be based on some kind of principle, or on some property of the empirical world. No reciprocal causal connection can be shown to obtain between parallel events, which is just what gives them their chance character. The only recognizable and demonstrable link between them is a common meaning, or equivalence (p. 115).