At the center of Wilber's philosophy is the so-called "AQAL" - All Quadrants All Levels - cosmology. This assumes a 4-fold holistic hierarchy, as explained here. This can be shown by the following diagram
But while impressive, this diagram also contains a lot of arbitrary assumptions, and there are many inconsistencies between quadrants and levels, as Kris Roose shows in his critique. To his concerns I'll add my own objection to this arrangement of levels and holons. It is simply this. While it is a viable hypothesis that eukaryote cells are symbiotic prokaryotes, and these cells are composed of proteins (absent in the above diagram, but they would be at 2 /12 in the upper right quadrant) , proteins of molecules, and molecules of atoms, it is not the case (regarding the triune brain - 7 to 10 in the upper right quadrant)) that the neocortex is made up of many limbic systems, or the limbic systems of many brainstems. Looking at the lower right quadrant, we see the reverse - the largest element is at no.1. Following Erich Jantsch, who Ken acknowledges among his sources of inspiration, these get smaller (reverse holism, 2 is a part of 1, not vice-versa), following Jantsch's evolutionary sequence, until 7 or 8, when they start to get larger again. And as for the left hand quadrant, you can't say emotions are parts of symbols, and so on.
Ok, let's say that the holons are not - as Koestler presents them, quantitative, but strictly qualitative. Each holon includes (as Wilber insists they do) everything of the subordinate holons, as in the following diagram.
This theme of the higher including all of the lower, but the lower doesn't have everything of the higher, occurs as early as The Atman Project. It seems to be an abiding Wilberian generalisation of how the universe works. Here again we have a problem. The rational logical mental processes do not include emotions but as psychologists from Freud to Stan Gooch have pointed out, these are two distinct processes. Myth is not the same as Rationalism. The neocortex develops on top of the limbic system, but is a distinct layer. Moreover we find in nature lots of examples of organisms that lost the faculties of their ancestors. And as far as the spectrum of consciousness goes, do we really have the richness of sensory awareness of our palaeomammalian ancestors and all our intellect as well? And what about disembodied beings, for example the disincarnate who no longer have a body? (Interestingly there does not seem to be any integration - or even any mention - of occultism in Wilber's corpus. Mysticism, yes. Occultism, no. This is part of Wilber's rationalistic bias)
Wilber states that this arrangement is merely a simple schematic summary to help further the discussion, and should not be taken dogmatically or cast in stone, and that
"each of the quadrants might more accurately be constructed as a branching tree, and not a simple straight line, indicating the rich variation within each grade and clade (each level and type). Each quadrant includes both hierarchies (or clear gradations) and heterarchies (or pluralistic and equivalent unfoldings within a given grade)."
This certainly constitutes a much better approach. But why isn't this explored more, in all the thousands of pages Wilber has written?
Another problem with Wilber's evolutionary-holonal hierarchy is that it literally endless: every holon is part of a bigger holon, and is made up of smaller ones, like the joke (which he himself cites) of "turtles all the way down" Not only is this an infinite regress, but it means that one can never attain the state of pure Spirit, because this is the "last" holon, and hence infinitely remote in terms of a linear evolutionary sequence (this inconsistency, like Wilber's "Two Truths" advaitism in general, is never explained.)
It might be argued that Wilber's integral system is not truely integral, as Wilber fails to unify the quadrants (the holon always being forever fourfold), and has to rely on a Two Truths style crypto-dualism (the relative vs the transcendental) to get to the One. Each quadrant has a quite distinct gradation or chain of being, and these only diverge further and further - there is no unifying principle at the end to tie it all together
Christian de Quincey in his on-line criticism argues that Wilber fails to address the "hard" mind-body problem. This is not to say that he denies unity - in fact he is a firm monist - but he sees the overcoming of duality (such as the "hard" mind-body problem) as only possible through a transcendent realisation of an advaitin-mahayanist sort. He says: "I maintain that any sort of genuine and immediate intersubjectivity can only be derived from nondual consciousness or nondual Spirit." [see Do Critics Misrepresent My Position? - A Test Case from a Recent Academic Journal]
Much as the advaitin-mahayanist monism at least provides a transcendental resolution to the Mind-Body problem, it does not provide an empirical solution. A serious obstacle here, I would suggest, is Wilber's bias towards "Da-friendly" monistic metaphysics. With esoteric teachings that could provide a resolution of the ungainly Double Dualism of Wilber IV either ignored or misunderstood (because they would go against Da's and his own understanding, and the compartmentalisation of genuine spiritual teachers and esotericists in only one of the four quadrants, Wilber remains bound by the Two Truths paradigm of Advaita Vedanta and Madhyamika Buddhism.
To create a unified system of knowledge, one needs some of precise methodology, and Wilber's approach, as intriguing as it is, has a number of problems in it. There is also a certain arbitrariness to his taxonomy. In his unification of all knowledge, Wilber associates seminal thinkers with each of the quadrants. So one would expect scientists to go in the upper right quadrant, sociologists in the lower left, and so on. However, here Wilber makes a surprising error. Have a look at the following tabulation and see if you can see what is wrong with it.
Yes, that's right, those philosopher-mystics like Aurobindo and Plotinus who explained literally everything, and like Buddha who taught the way of liberation, are placed in the same box (upper left) as Piaget (developmental psychology) and Freud and Jung (psychoanalysis and the unconscious)! It almost seems as though Wilber, in undertaking his completely valid critique of the fragmented, specialised, postmodernist approach to knowledge, has himself becomes a postmodern relativist. The Absolute Reality that Plotinus and Aurobindo clearly described, and Buddha pointed towards with his anti-metaphysical pragmatism, has been exiled to one of the four quadrants, the one that is also about psychology (shades of Freudian reductionist and Jungian quasi-reductionist approach to mysticism!) Absolute Consciousness is now just one thing among many, and the basic principle even of Monism is lost. Is it any wonder that he was to later retreat from metaphysics to a more Mahayanist (Madyamika and Yogachara) sort of teaching? He had painted himself into a corner!
Yet the above quandary can be so simply resolved. All Wilber has to do is place a circle in the middle of his AQAL mandala, to represent the Origin from which the four dualistic quadrants have emanated, and locate Buddha's, Plotinus', and Aurobindo's teachings there. Freud, Jung, and Piaget would very correctly be grouped together in the Individual Subjective quadrant (the psyche), and there would be no reductionist confusion of Absolute Consciousness with psychology.
Despite the introduction of states (temporary states of consciousness), lines (multiple development of the various parts of one's being), levels (evolutionary attainment), and waves (cultural-collective) in the AQAL model, this philosophical construct still retains the same weakness of Wilber II; it is rigidly linear. The problem is that there is only one road from primordial consciousness ("pleromatic") to highest enlightenment ("ultimate"). Even though the different parts of the being, and individuals verses the collective, can travel this separately, they still only can go in the one direction, and they still have to follow all the same signposts. The overall impression is of a sort of cosmic clockwork, like the evolutionary-occult cosmologies of Steiner and Leadbeater, with their rigid series of Rounds, Root Races, Sub Races, and so on, but here applied to individual and social development. Throughout, the rational bias of secular western civilization is maintained - the primitive magical-mythic "Phantasmic-Emotional" and "Rep-Conop" stages are superseded by the rational logical "Formop" stage, and from there one progresses to the "Psychic" nature mysticism (the Judeao-Christian misconception of "pantheism" as an inferior state), then the more developed theistic religious (deity) mysticism of the "Subtle" stage. This is in turn superseded by the monistic (Advaitin-Mahayana) unitary realisation of the "causal", which itself is surpassed by a few great beings with access to the Zen and Mahamudra-like "Ultimate", thus reflecting the transhumanist bias for impersonal monism over theism, and the very worldy interpretation of Zen (Mountains look like Mountains again, so the mystical experience does not threaten one's comprehension of the world). As Arvan Harvat points out:
"(Wilber's) central fault is that he tries to perspectivize all human effort and physical evolution as ladders leading towards unitary mysticism. Mozart or Napoleon are not "ladders" to Nagarjuna, and neither is Luria. This is preposterous condescending attitude of an, as Polish writer Milosz would say, "captive mind"."
Nor should realisation and liberation always be the same; in fact it is ridiculous to assume a single state of "Ultimate". As Sri Aurobindo states
" In liberation the individual self realises itself as the One (that is yet Many). It may plunge into the One and merge or hide itself in its bosom - that is the laya of the Adwaita; it may feel its oneness and yet as part of the Many that is One enjoy the Divine, that is the Dwaitadwaita liberation; it may lay stress on its Many aspect and be possessed by the Divine, the Visishtadwaita or go on playing with Krishna in the eternal Vrindavan, the Dwaita liberation. Or it may, even being liberated, remain in the Lila or manifestation or descend into it as often as it likes. The Divine is not bound by human philosophies - it is free in its play and free in its essence."
In short, the impression I get from all this (and please correct me if I'm wrong here) is that Ken Wilber went as far as the mental faculty, unaided by cosmic gnosis, could go. Although he has an excellent insight into Pure Consciousness Unmanifest Absolute and Monism in itself - as expressed in Advaita, Mahayana Buddhism, and the teachings of Adidam, this in itself does not allow him to overcome the double dualism inherent in even the Koestlerian aspect of his AQAL model. As Arvan Harvat notes in his perceptive review/critique [A Glance at Ken Wilber's "A Brief History of Everything"], this predisposition for non-dual visions of Reality prevents Wilber from seeing the richness and profundity of the more nuanced and complex doctrines of Hermetic, Rosicrucian, Lurianic Kabbalistic and other esoteric teachings. I agree that in those representatives of the Western Wisdom tradition, with their emphasis on the way in which the One becomes the Many, and for that matter also in Indian emanationist doctrines like Kashmir Shiavism, and a truer understanding of the teachings of Sri Aurobindo, that the solution to the problem of the One and the Many is to be found.