Despite the 400 years or so of hard science since the time of Newton, the nature of human consciousness has evaded close scrutiny and remains, in contrast with the rest of the world, a kind of mysterious anomaly. Whilst we may know a great deal about atoms, molecules, chemicals, genes and stars, we know little about the 'stuff' of which consciousness is made and how conscious minds somehow manage to infuse and, indeed, give light to the physical world. For one cannot weigh conscious thoughts. One cannot put consciousness under a microscope. And yet a scientific instrument such as a microscope owes its existence precisely to the conscious human mind which designed it. In this sense, consciousness is obviously a fundamental property of the world as we know it. Understanding how consciousness fits into an otherwise physical Universe is therefore essential if we wish to fully comprehend the nature of reality.

One approach to understanding how consciousness fits into the physical world is to consider the actual intersection where the physical and mental worlds indubitably meet. This intersection, if we can manage to hone in on it, can be considered a bridge linking mind and matter. If we can examine the bridge from near and afar alike then perhaps we will see more clearly how mind and matter are involved in the totality of Nature and thence understand the dynamics and interplay of each. Or at least we might understand how the two ends of the bridge relate to one another.

Illuminating the Bridge

The mysterious bridge between physical reality and psychological reality is clearly transversed whenever psychoactive substances are ingested. This is so because such substances, whilst being physical, nonetheless dramatically alter the content and general quality of consciousness (i.e. physical 'stuff' alters psychological 'stuff'). This plain and simple fact implies that any researcher interested in the mind/body problem, with how consciousness resides in an apparently materialistic Universe, would do well to consider the action of psychoactive substances, especially those which unleash to the greatest changes in consciousness. By looking closely at the way these substances unleash their effects, one is unveiling the mysterious bridge between the physical and the mental.

Of those drugs serving to highlight the intersection of the physical world with the mental world, entheogens, or psychedelics (or even hallucinogens as they are more commonly, but inaccurately, known), prove the most interesting since they cause the most dramatic changes in consciousness known to man. By analysing their modus operandi, by tracing their action within the brain, we ought to be able to say something definite about the 'stuff' of consciousness' and how this 'stuff' can be altered through purely physio-chemical means. In this way, we might understand more fully just what consciousness is, its relationship to physical matter, and why the mind is so evidently mutable.

Tracing the Effects of Psilocybin

Let us consider psilocybin, a fungus-derived entheogenic alkaloid long employed by mankind to induce an altered state of consciousness. The peak effects of psilocybin include vivid visionary episodes with eyes closed as well as a felt communion with the Other and as well as numerous other transcendental experiences. In short, psilocybin induces a massive alteration in consciousness, that mysterious mindstuff of which we are, in part, made.

Now, realising that psilocybin is a chemical with a known physical structure and bearing in mind that it serves to profoundly alter consciousness once it has reached the brain, can we not focus on this process and so make out the place where the actual physical and mental realms meet? In other words, at some stage after ingestion, physical psilocybin touches upon, or directly influences, non-physical consciousness. The two realms clearly merge with one another somewhere along the line and at some definite point or locale. The two realms of Descartes, mind and matter, seemingly separate and irreconcilable in the eyes of many scientists and philosophers, thus interweave at some point. The bridge is crossed. This is patently of interest if we wish to understand the nature of mindstuff.

A cursory look at the literature reveals that much is known about the physical structure of psilocybin. For instance, its molecular configuration is precisely known. So too is psilocybin's absorption by the human body and route to the brain understood in detail. However, when it comes to understanding psilocybin's subsequent action within the nerve cells or neurons of the brain (i.e. we approach the centre of the bridge), knowledge is less forthcoming but even so, a few things are still known about this stage. For instance, it is believed that psilocybin mimics serotonin, a neurotransmitter involved in relaying electrochemical impulses between individual neurons. In other words, it is thought that psilocybin works its powerful effects upon consciousness by infiltrating certain neuronal systems of the brain which utilise serotonin.

The Bridge Gets Fuzzy

From this point on however, certainty becomes more and more vague for only gross generalisations can be made. Since a cascade of events on a molecular scale are unleashed once psilocybin reaches the brain it is impossible to analyse each and every individual neuron effected. Indeed, considering that the human cortex is constructed of literally billions of neurons, who can say which one hundred, or which million, serotonergic neurons are effected by psilocybin? Not to mention of course, the subsequent effects of such altered patterns of neuronal firing upon further streams of neuronal firing.

In effect, what this means is that the centre of the bridge we are keen on delineating, the locale where the physical world of psilocybin intrudes upon the apparently non-physical world of thoughts, emotions and perception, is occluded to us due to the sheer complexity involved and the impossibility of accurate measurement. Whilst we can make certain generalisations and even see certain global events in the brain via magnetic resonance imaging techniques administered to subjects previously given an entheogen like psilocybin, all we really acquire is general knowledge. We can say general things whereas with regard to the precise and detailed action of psilocybin upon individual neurons and the subsequent chain of effects upon neuronal firing patterns, we can say very little. In fact, we can reason that the difficulty of complete knowledge and the degree of uncertainty facing us rise exponentially with time. From absolute certainty over psilocybin's molecular structure, uncertainly escalates once the drug has crossed the blood/brain barrier, more and more so as time proceeds and cascades of neurological modifications are wrought.

The Other Side of the Bridge is Clear

Certainty begins to rise again when we consider the concurrent mental events taking place within the psilocybin user's mind. Users will often describe in vivid and exacting detail the experiences they are having. Visions can be avidly described as can the perceptual changes being experienced. Indeed, experiences from many users can be collated and this can lead to general statements about the effects of such entheogens. Again, we witness a fair degree of certainty in stark contrast to the vast chasm of uncertainty involved in psilocybin's neurological effects.

This is the nature of the bridge then which separates mind and matter. We can see clearly and with certainty at each end. Somewhere in the centre however, details become obscured and we can only make out hazy features. Right in the centre we are clueless, save only an appreciation that there are webs of neurological complexity involved.

In thinking of this image, of certainty connected to certainty via a complex cascading web of uncertainty, one might be reminded of a fractal boundary - where a seemingly solidly outlined boundary is revealed, upon close inspection, to be made up of an interconnecting pattern.

One can also imagine the two realms of certainty as the top and bottom parts of a thick line, starkly black, the ends of this line representing the clearly describable worlds of physical psilocybin and its concurrent psychological effects - both areas essentially definable and documentable by science. Somewhere along the middle section of this stark black line however, at the point where we perceive a web of neurological complexity involved in the pharmacology of psilocybin, there is a kind of fractal breakdown of certainty. One can imagine the stark black line veering off and then adopting some fractal shape as it meanders back in on itself in a fractal manner. However, it should be noted that despite this fractal meandering, there is no actual breakage of the line. And this is rub. For in realising that the line is essentially continuous, albeit fractally so, we are thus intuiting that the worlds of mind and matter are likewise joined, not two separate and mutually exclusive domains at all but a single domain whose boundary is fuzzy and full of complexity. In other words, the two worlds join, matter and mind resolving themselves as part of some as-yet ill-defined continuum just as all the patterns within a fractal are part of one interconnected whole.

If this is so, if the aforementioned analogy with the fractal boundary be in any way accurate, then we shall have to admit into our conceptual paradigms about the world the notion that mind and matter are not really so distinct, rather that they are the two ends of a single continuum, a continuum which is so complex in some places that we see only a boundary, or at least find it easier to invoke some sort of boundary. However, considering the real fact of psilocybin's effects upon consciousness and the chain of reasoning which sees a continuous series of processes linking the drug to an altered state of consciousness, we really must concede that Cartesian dualism is redundant. In its place we might instead see the world, or Nature, as consisting of one single stuff in which all parts are related to one another and potentially able to influence one another.

Perhaps the best way of describing this single system is in terms of information or energy. Which is to say that both mind and matter are made of the same sort of essential stuff, the caveat being that this stuff can be in radically different forms. What we call consciousness could then be defined as an informational or energetic 'stuff' as could material things.

Whatever the virtue of these speculations, it is clear that the mysterious boundary between mind and matter is not a boundary at all - or at the very least it is a fractal boundary wherein mind and matter do in actuality converge at some indefinable point. Since this must be so, since mind and matter must surely be manifestations of a single continuum, then it implies that we, us, our selves, are intimately woven into the rest of Nature just as motifs are woven into a carpet and just as a bass note is woven into the symphony of which it is a component part. Cartesian dualism is not longer tenable. Everything, even our conscious thoughts, is part of everything else. The Universe thus resolves itself as a single 'solid' system, forever forming itself into novel patterns of exquisite complexity, souls included.