In what sense do we know, to any degree, that totality of which we are a part? And to what extent might our actions be rendered futile by the confusion of our knowledge? These questions go to the heart of the human condition and have for millennia been the concern of religion, philosophy and (more recently) science. For much of this history, and in many cultures, the questions have been answered by appeal to a hierarchy of ways of knowing – an ascending chain of types of knowledge, each superior to the one below, in the sense of incorporating and going beyond it. This conception of knowing has been widely documented and studied.

Our aim in this book is to consider the possibility of alternative structures of ways of knowing, using the relationship between science and mysticism as a focal test case, and appealing to the latest psychological understanding that human beings have two or more ways of knowing or levels of processing, which provides an example of an alternative structure. This introduction gives a satellite view of the territory (though inevitably one slanted to my own interests) whose details will be explored by the particular essays.

The move towards a hierarchy of knowing was famously articulated by Plato, but certainly preceded him. In his allegory of the cave he compared the deluded "opinions" of those unversed in philosophy to the impressions gained by prisoners shackled within a cave, able only to see the shadows cast on its wall by the passage of real events taking place in the light behind them. True knowledge, as opposed to opinion, could only be gained by a transformation of one’s way of knowing, a mental turning round so as to perceive the three-dimensional reality that had produced the indistinct shadows. Reality lay in the eternal truths thus revealed, and not in the shadow world of changing appearances.

From this allegory developed the hierarchies of knowing first developed in neo-Platonism and then refined in Platonically influenced Christendom. In most cases, a hierarchy of realms of the known matched the hierarchy of ways of knowing. Most influentially, Plotinus established the ascending sequence of Soul, Intellect and Unity. Soul was the domain of principles, eternal in themselves, but bound to material beings, which could be discovered by Reason. Intellect was the domain of pure Ideas independent of matter and known by intuitive revelation. And Unity denoted a realm of undifferentiated being, unknowable in any normal sense, but possibly open to participation in unitive mystical experience. A variant of this, publicised by Wilber, was the later scheme of Bonaventura who described three ways of knowing in terms of three "eyes", of the body, the intellect and the spirit.

Those who have developed critiques of this kind of structure have drawn attention to the way in which a hierarchy of ways of knowing tends to be connected with a hierarchy of political power among classes of a society. The higher ways of knowing, because they each incorporate and supersede the lesser ones, are acquired by longer study, and so accessible only to those with the economic resources needed for leisure. Superior knowledge would then become the prerogative of an educated rich elite. It might be questioned, however, whether this superior knowledge favours or hinders the wielding of political power. In the empire of Ashoka the mystics flourished, but not in the empire of Attila. Arguably, the history of religions is structured by the attempts of institutions to embrace the differing powers of Attila and Akosha.

While the growth of science (natural philosophy) in the early Islamic world took place within a scholastic structure that was aligned to a spiritual hierarchy of knowing, when this impetus passed to the West there was a growing tendency for scientific learning to develop independently of the church, leading to relations between the church and science that were often tense or hostile. From the start, the more diplomatic thinkers on both sides developed an agenda of regarding the scientific and revelatory ways of knowing as complementary, having validity in different domains. Thus Osiander, in his preface to the work of Copernicus, argued for its utility in navigation, largely ignoring the metaphysical claims which the book actually contained. A conception of parallel, rather than hierarchical knowledge systems led to a division of the intellectual territory, tracts of which were successively ceded by the church in strategic withdrawals from the attacks of Copernicus, Darwin, Freud and Hawking.

This established in science one form of an alternative to the hierarchical structure of knowledge. In recent years, however, feminist thinkers have realised that while these men of science and men of the church negotiated their alliances of power, a quite different sort of alternative to hierarchy was maintained by the persistence of what Mary Grey, following Foucault, termed "subjugated ways of knowing", including the practical and spiritual knowing of women, until quite recently handed down orally and unrecorded in the histories written by men. The knowledge hierarchy was identified as a patriarchy, and it became clear that the collision between the subjugated women’s knowing and the patriarchal/hierarchical knowing of the church had resulted in the witch trials that culminated in the sixteenth century. A similar pattern was played out in the case of the indigenous peoples of North America, Australia and the other lands that were conquered by the dominant power of the West, and whose cultures then contributed to the hidden wealth of the subjugated ways of knowing.

Any scheme involving different ways of knowing naturally suggests a division of the human being into different parts, or at least different faculties, corresponding to these different ways. Plato again stands out as an expositor, with his graphic depictions in the Republic and the Phaedrus of the division of the human into body and soul, as separable components. The metaphor of the three eyes of Bonaventura also suggests a tripartite division of the human, which is followed in different ways in several cultures. There is also a tradition of the parts of the human fitting badly together, or being at odds with each other. St. Paul was famously frustrated by the way that "the good that I would I do not: but the evil which I would not, that I do … I see another law in my members, warring against the law of my mind". On this tradition there is something basically wrong about the misfit between the parts of the human being – but until recently science could shed little light on this.

Cognitive science now comes to the rescue. Research into memory and information processing has produced a number of models suggesting parallel but separate ways of knowing. I am here going to focus on the Interacting Cognitive Subsystems (ICS) model which represents perhaps the most complete and sophisticated integration of the experimental data. In addition, it serves as a model in which a division is not made hierarchically, into good and bad, or bad, good and better, but "laterally", so to speak, into systems that are operating in parallel and are all necessary. This model sheds crucial light on the relationships between the alternative ways of knowing outlined above, which otherwise seem rather confusingly intertwined.

ICS, as an information processing model, is based on experimental evidence for different forms of coding information; for instance, immediate and sensory based coding, verbal and logically based coding, or a more holistic, meaning based coding. These and other distinct codes form the basis for nine postulated subsystems. Three are sensory and proprioceptive; two involve higher order pattern recognition; two, the production of response; and two are meaning based systems at yet a higher order. It is on these last two, which Teasdale and Barnard call the propositional and the implicational subsystems, that I will focus here.

As Isabel Clarke (2001:136) expresses it,

This concept of the split mind, deriving from functional considerations, is probably closely related to the concept of the distinction between the mind as it perceives itself in ordinary (or "deluded") consciousness and the essential reality of mind, a concept deriving from introspective examination. When the implicational/propositional distinction is examined in detail, however, it becomes clear that it opens up a quite different dimension from the hierarchical model, in that – while there may be elements of an evolutionary distinction between the propositional and implicational systems – their relationship in the modern human is not hierarchical. While the propositional aspect is most dominant at the level of Plotinus’ Soul, for example, it is the implicational level that is dominant both at the higher levels of unitive mysticism and at the lower levels of the Eye of the Body that sees the immediate presence of the physical. The implicational system is concerned with Being, at every level of hierarchy, while the propositional system is concerned with rational representation, which has only a restricted range of applicability. The cultural history outlined above can now be seen as one of progressive political domination by an emphasis on the propositional subsystem, to the detriment of mysticism in religion and of indigenous and feminine spirituality, and to the benefit of science and of the engineering applications that flowed from it.

It cannot be stressed too much that, because all our meaning-making flows through these two subsystems, they determine our universe, in so far as it is knowable by any form of thought. We are thus dealing with a much more fundamental level than, say, the more publicised "right-brain/left-brain" division, which refers to different balances of ability in handling the (given) universe.

The move to a recognition of ways of knowing that are alternative to the hierarchical model poses a challenge to our logical construction of the world. Science is used to the idea of a hierarchical sequence of steadily more inclusive theories, each one containing the previous as an approximation or special case, with the whole system conforming to a consistent classical logic. In Wilber’s version of Bonaventura’s scheme, the bodily level is pre-logical, the intellectual level logical, and the spiritual level beyond all logic; so that the scheme is clearly situated in relation to classical logic. What, however, are we to make of a division of ways of knowing that situates different ways alongside each other, rather than having each one superseding the previous ones?

The co-existence of different ways of knowing that appear, on hierarchical way of thinking, to be inconsistent, suggests that we are somehow suspending the normal laws of contradiction. Rather that seeing the different views as exclusive alternatives, either of which might hold but not both, we are being enjoined to consider that both one alternative and the other are in some way valid. The phrase "both/and thinking" has gained currency as a loose way of characterising this. Such a move cuts across the whole tenor of Western (and much non-Western) philosophy, which has been motivated by the quest for a method leading to comprehensive and exclusive truth. For realists and quasi-realists truth lies in external reality; for Kant and his successors truth lies in the a priori preconditions of our own thinking – but for both truth is absolute. The idea of alternative ways of knowing based on alternative ways of thinking entirely undermines this conception of exclusive truth.

One response to this undermining of classical truth has been the post-modern project of grounding knowing in particular cultural and political contexts. This has been a vital contribution, but there has remained a gap to be filled. While many writers have affirmed a distinction between post-modernism and pure relativism (the total absence of any concept of truth), the nature of this ground between absolute truth and relativism has remained elusive. One motivation for the present work is the emergence from quantum logic in physics and from the study of bilogic in analytical psychology of the idea of a context dependent logic which incorporates a non-classical notion of truth that allows us to see the richness, if not the solidity, of this middle ground. In a later chapter I describe how the mathematics of topos theory gives a precise logical framework for context dependent logic that unites the biologic of analytical psychology with modern quantum logic.

Rodney Bomford has described the central role of bilogic in the conceptualisation of mystical experience. In the past this has been described in terms of paradox, which has sometimes been seen more as a rhetorical form than as a reflection of the reality of the experience. The links that we have established between the implicational subsystem, mystical experience and context dependent logic now bring mysticism into a full dialogue with the scientific approach to the world.

We live in a world in which the dogmatic and intolerant factions of religions are on the increase. The language of these factions is marked by exclusive either/or thinking and by emphasis on propositional knowing at the expense of knowing through experienced presence, accompanied by an emotional charge that comes from a perception of threat to the self arising from an implicational subsystem that is dissociated from the propositional one. The two parts of the split mind are out of joint, resulting in escalating cycles of aggression and violence.

The way forward has to involve integration: of the two ways of knowing that have become sundered, and of the parts of society that carry the riches of each of these two ways – an integration that, resting on both/and logic, recognises the radical distinction of the parts and does not try to subordinate one to the other. Such integration is a spiritual project, though it can gather its tools from aspects of science. Since, as we have seen, spirituality is crucially dependent on the implicational way of knowing, it follows that the key to a global spirituality lies in the hands of those whose faithfulness to this way has led to their repression by the dominant society – with the women and the indigenous peoples, with the anawim , the downtrodden, to use a term from Jewish and Christian spirituality. Among the anawim are also many whose openness to the implicational way of knowing has led them to be labelled as psychotic by the culture dominant today, who in earlier societies would be recognised and encouraged as potential seers.

Viewed in this light, the dialogues painfully conducted between religions, and between religion and science, can be seen in a new way. It has often been suggested that in such dialogues the mystical strand has a paramount role in leading to integration, and this is understandable when we realise that the mystical, which can only be accessed through openness to the implicational way of knowing, brings with it the ability to navigate the context-dependent logic of the implicational and thereby transcend the separations of the exclusive logic of the propositional.

We have known this for many years, through the writings of mystics such Nicolas of Cusa, through the analysis of the nature of dialogue by David Bohm, through the work of philosophers of science such as Nancy Cartwright, through the work of feminist theologians such as Mary Grey. What is new is an understanding of precisely how our failure or our success in achieving this integration is concretely embodied in the structure of our minds, in the nature of being human, and how the solution is manifest in all domains: the social, the physical, and the spiritual.