One could view Jung's concept of Synchronicity as an example of the activiation of a vestige of the bicameral mind after the rise of consciousness in human history and experience. The upshot of accepting Jaynes' proposal that many of the early civilisations started with a bicameral mind is that when the breakdown occurred there would still be a remnant, a shadow of bicamerality surviving in the minds of individuals, a vestige of the organizing principle which governed those societies, a collective unconscious, as Jung would put it, or the Gods of the Ancient World as Jaynes would put it. Jaynes supposed that this vestige was to be found in the modern world with the auditory hallucinations of schizophrenics - involving what these days would be called an external locus of control - in this case, a voice appearing to come from the outside guiding the schizophrenic to specific actions.
So, how does that link in with experiencing a synchronicity for most of us, considering the auditory hallucinations with those of abnormal consciousness would not be present in normal individuals? Despite the general absence of abnormal states of consciousness in normal individuals, the vestige of bicamerality would still exist. One might consider the effect of this vestige as drowned out by the hustle and bustle of the world of consciousness. Thus, the guiding principle takes more subtle and more arbitrary forms by guiding conscious attention via the preconscious: hence, when this vestige of the bicameral mind is activated more than usual, individuals may experience a meaningful coincidence, or a series of them. Whereas, with the Schizophrenic, many more threads of experience enter consciousness simultaneously, bringing with them a more complex notion of causality that is simply not accessible, or indeed intelligible, to the normal individual with a more or less fully modern consciousness. Schizophrenia, as Jaynes' might have put it, is at the boundary of modern consciousness and bicamerality, a form of being caught between two worlds.
The thesis Jaynes' presented involved the activiation of the right side of the brain - specifically the right side equivalent of Wernicke's area. This area and the local areas surrounding it are associated with music and poetry and decision making. Everyone knows that music and poetry have a rhythm to them - a rhythm filled with motifs, basic feelings and archetypes. An analysis of synchronicities would bear out much the same. It is quite clear in the individual experience of a meaningful coincidence that it is poetic and burdened with metaphor and has a rhythm to it. Even if an individual cannot pin down a cause to the synchronicity which makes the experience feel uncanny, the consequences, the effects often can. Jung presents examples in his book. The feeling of uncanniness associated with synchronicity, in this thesis, would be the result of modern consciousness and its internal locus of control which impedes understanding by the very fact that it is a left-brain analytical phenomenon rather than a right-brain intuitive and poetic phenomenon.
Here I think it is important to include Rupert Sheldrake, the originator of the concept of Morphic Resonance. In Part One of his essay, Mind, Memory and Archetype Morphic Resonance in the Collective Unconscious, Sheldrake emphasises the importance of holism for his work. With regards to rat psychology he had this to say about the development of form, structure or organisation,
"There are quite a number of experiments that can be done in the realm of biological form and the development of form. Correspondingly, the same principles apply to behavior, forms of behavior and patterns of behavior. Consider the hypothesis that if you train rats to learn a new trick in Santa Barbara, then rats all over the world should be able to learn to do the same trick more quickly, just because the rats in Santa Barbara have learned it. This new pattern of learning will be, as it were, in the rat collective memory-in the morphic fields of rats, to which other rats can tune in, just because they are rats and just because they are in similar circumstances, by morphic resonance. This may seem a bit improbable, but either this sort of thing happens or it doesn't.
Among the vast number of papers in the archives of experiments on rat psychology, there are a number of examples of experiments in which people have actually monitored rates of learning over time and discovered mysterious increases. In my book, A New Science of Life, I describe one such series of experiments which extended over a 50-year period. Begun at Harvard and then carried on in Scotland and Australia, the experiment demonstrated that rats increased their rate of learning more than tenfold. This was a huge effect-not some marginal statistically significant result. This improved rate of learning in identical learning situations occurred in these three separate locations and in all rats of the breed, not just in rats descended from trained parents."
Now, whilst rats (in some cases?) are not humans, Sheldrake thinks that the same kind of phenomenon can apply to us. In terms of Jaynes' work, the bicameral mind, the organising principle of ancient cultures, was the outcome of morphic resonance in ancient human societies, which is to say that it was the resultant morphic field, and in modern societies, relating Jaynes' to Jung's work, Synchronicity is the result of modern consciousness drowning out the vestiges of the bicameral mind. As an aside, it can be seen that some of the analogous achievements of ancient culture might not be through traditional modes of communication, but by morphic fields, by not only full bicamerality, but by its vestiges as modern consciousness emerged from its breakdown. Indeed, the vestiges of bicamerality in association with the the concept of morphic resonance might bear out an explanation for the virtual simultaneity of many inventions, though, of course, individuals with access to the same kind of information may come to similar conclusions purely through the left-brain analytical means of thought, text and speech. However, it remains the case that, with this alternative thesis, another form of communication may also be at work, leading to synchronous developments via subtle cues, rhythms and resonances, a language accessible only to the musical, and poetic right-brain. In that world, mankind sings.