Roberts, F.S. (1992). A possible non-physiological basis for perception and a defence of dualism. JSPR 58, 250-257
Reproduced with the kind permission of Peter Roberts.
List of papers by the author; archived at

A possible non-physiological basis for perception and a defence of dualism

by F. Somerville Roberts

An assessment of Tyrrell's 'idea-pattern' theory shows that its influence on parapsychology and dualism has been seriously underestimated. The radical change in approach to these two subjects which can result from fuller appreciation of it is discussed. Experimental examples are described indicating that Tyrrell's concept of a non-physiological element in consciousness is possibly, or even probably, correct. The effect of this situation on the theoretical aspects, and future research, of parapsychology are considered.

The introduction of the 'idea-pattern' concept in Tyrrell's theory of apparitions was probably one of the most significant steps forward in the slow progress of parapsychology. Its implications are fundamental, not only for its intended application to apparitions, but for the whole field of mental parapsychology and for its influence on the dualistic approach to consciousness. Unfortunately, its value has not been sufficiently appreciated in these areas. This is probably due to the fact that Tyrrell related it solely to apparitional phenomena. He offered no confirmatory support from other areas, and he was applying it in a field which many investigators regarded with some scepticism and mistrust. It is not surprising that it has aroused little interest or enthusiasm.

It may be that Tyrrell did not realise the full potential of his theory in areas apart from apparitions, although he did once refer to its application to hypnotic hallucinations, but as he first propounded it in a Myers Memorial Lecture he may have been limited by his terms of reference. Its value lies in the fact that, in addition to apparitions, it provides a single explanation for a wide range of perceptual phenomena, each of which requires its own ad hoc physiological hypothesis. This situation is due to a certain extent to the fact that Tyrrell's theory embodied three original concepts which, if assessed in detail, suggest an entirely new approach to perception, and even to the nature of consciousness itself.

The process of normal vision is too well known to require description here. It is sufficient to be reminded of the fact that, when we look at something, the characteristics of the resulting retinal activity are transferred to the visual cortex, where they create the corresponding electro-neural and molecular patterns. Some investigators maintain that this brain state is the final stage of perception and constitutes our sensation and experience of vision. Others claim that a further stage of cerebral processing is necessary, but even if this is so, it is still a brain operation.

The alternative approach, dualism, maintains that the brain pattern is apprehended by an element of consciousness (the self?) which constructs the image from the sensory details presented to it, and which also processes and interprets the image. The mental image, although regarded as non-cerebral, is directly caused by the brain state, which it normally follows precisely in detail. This is an essential evolutionary outcome, because if sometimes the image included items for which there was no physical detail in the visual cortex, or if some retinal detail were omitted, life would clearly be impossible. The obvious conclusion is that the perceptual image is caused by the brain configuration.

Tyrrell proposed three fundamental modifications to the existing dualist outlook. Instead of being directly linked to sensory stimuli, he suggested that, as the stratum of consciousness responsible for perception was not physically linked to the cortex, it was not necessarily dependent on it. This contradicted what was generally accepted, but it was a necessary step in the formulation of his theory. Unfortunately, he failed to put forward any evidence or observations to support this hypothesis.

As a result of this step he was able to suggest a second concept, to the effect that this level of consciousness could possibly respond to other initiating agents in addition to sensory stimuli, and it is clear that what he had in mind was probably the telepathic initiation of apparitions. That he was correct in his thinking is confirmed by the fact that other agents such as volition and hypnotic suggestion can be shown to be equally capable of creating perceptual images indistinguishable from those originated by sensory stimuli.

Tyrrell's third point was that if originating factors additional to sensory stimuli were operating, then the dominating agency was the one which created the percept. This implied, for example, that the sensory system could be functioning normally, but the image actually perceived could be something quite different, although on occasions it could be composed of both sensory and non-sensory elements. Again the influence of the apparition on his thinking is plain.

The ‘idea-pattern’ hypothesis is dependent on the fact that images induced by non-sensory sources appear as 'real' to the observer as do retinal images, and there is ample evidence indicating that hallucinatory images are indistinguishable from sensory. Much of this is provided by experiments carried out under hypnosis, but even simple tests with a repeatable phenomenon, such as the voluntary control of perception, confirm this fact. There seems little doubt that hallucinatory percepts comprise the same elements as sensory percepts, are constructed in the same way and exist in the same level of consciousness.

At this point it is interesting to note how the composite 'idea-pattern' theory can explain typical manifestations of perception. No attempt is made here to offer a parallel physiological theory as it is obvious that any such hypothesis must necessarily be exceedingly complex. Take, for example, normal vision. If we close one eye, the brightness of the field of vision is not appreciably reduced. The optical system is, of course, a physical system, and in any physical system in which the output is dependent on the input, any change in the input, such as halving the illumination, must produce a corresponding reduction in the output, in this case the illumination of the field of vision, but this does not take place. This would appear to contravene a basic law of physics.

The 'idea-pattern' theory would claim that one retina will provide all the information necessary for consciousness to create a fully detailed image of the field of vision and the second eye adds nothing more than three-dimensional perspective. Therefore it is to be expected that closing one eye will not significantly affect the field of vision—which, of course, is actually the case.

An interesting application of the 'idea-pattern' theory is the explanation of hallucinations induced under hypnosis. As already pointed out, these are as real to the percipient as equivalent sensory percepts. It follows that if a hypnotised subject is instructed that there are, for example, flowers on a table which is in fact empty, he will not only see a bunch of flowers, but will be able to smell and touch them.

The initiating factor here is nothing more than a varying air pressure on the ear-drum of the subject. Physiologically, the resulting electro-neural signals have to separate themselves into those destined for the visual cortex and the tactile and olfactory areas of the brain. These signals must carry the precise information necessary for the creation of flowers with their characteristics, they must know how to travel from the ear, or the auditory cortex, to the relevant brain areas and, above all, how to manipulate these areas so as to create the patterns corresponding to the image of a scented flower.

With the 'idea-pattern' theory, the hypnotist's instruction generates the idea of flowers within the subject's consciousness and from it is created an image of flowers, complete with appropriate scent and texture, just as if the originating agency had been sensory.  similar example, but one concerning which there can be no doubting the veracity of the observed data, is the perceptual experience of pain. If a hypnotist informs a subject who is suffering severe pain that the pain will disappear, it will immediately do so. This has been proved by thousands of surgeons, obstetricians and dentists all over the world and illustrates the validity of the creation and control, under hypnosis, of all forms of perceptual experience. Again, with the 'idea-pattern' hypothesis, consciousness acquires the belief that there is no pain, and the ensuing perceptual experience is accordingly free from pain.

The phenomena associated with the voluntary control of perception afford a marked contrast between the difficulties of providing a physiological hypothesis and the more readily acceptable 'idea-pattern' theory. A typical example of this phenomenon is that of a rotating object which, by the exertion of 'will power', will apparently reverse its direction of rotation. It must be pointed out that the volition image has all the characteristics of the retinal image and is indistinguishable from it, except that the rotation has been reversed. When this takes place the image, or brain configuration, has been altered, but not as a result of retinal change—the optical system continues to convey the actual directional signals to the visual cortex. However, since the perceptual image, on a materialist basis, is a physical system, any change in it must be the result of a physical force. Such a hypothesis can be regarded as valid only' if it meets the normal criteria of a physical theory; for example, that it explains the nature and operation of the phenomenon concerned, and gives adequate answers to relevant questions such as the following :

(a)    This physical force must originate somewhere. Where?

(b)   How does it originate? The normal explanation would be as the result of a prior physical action, but this could lead to the dangers of an infinite regress. It might be claimed that it could arise spontaneously like the fission of a radioactive atom, but an unpredictable, spontaneous and atomic reaction of this type has no relationship whatsoever with the controlled, predictable and detailed change of a complex percept.

(c)    How does it find its way to the requisite area of the visual cortex ?

(d)   How does it know which cells it must not affect? (Those which constitute the background remain the same whether the image is retinal or voluntary, and must not be interfered with.)

(e)    How has it been programmed to recognize the direction of rotation, so that it can reverse it?

(f)     The retinal electro-neural signals have been programmed to modify the visual cortex so as to correspond always to the retinal pattern. The volition force has had no such programming. How does it know the procedure necessary to modify the brain pattern to result in the required image?

(g)    What power does the volition force possess which enables it to obliterate the existing retinal pattern, so that it can replace it with its own design?

(h)    And so on.

 This is the type of question for which a materialist theory must provide an acceptable answer if it is to continue to receive serious consideration. It is useless to claim that the nature and function of such a force cannot be determined at present because we do not know enough about it, or because the brain activity involved is far too complex to allow us to understand its operation. Nor is it any longer acceptable to assert blandly that "such questions can be explained by orthodox science" or that "they can be explained with reference to physiological and psychological aspects of the human brain " and simply leave it at that. The reason why these techniques can no longer be adopted is that the 'idea-pattern' hypothesis can explain the voluntary control of perception, auto-kinesis and many other perceptual phenomena, and also satisfactorily accommodate the foregoing questions. For example, in the case of the apparent reversal of the radar scanner, the idea of reversed motion is generated in the consciousness by volition and accordingly that is the image which is created and observed.

Another type of example is auto-kinesis, in which a stationary dim light in an otherwise totally dark room is seen to move in any direction at random. Numerous physiological theories based on the possibility of moving particles in the aqueous humour, corrective signals to prevent the eyes from moving, etc., have been suggested but none has been regarded as generally acceptable, and none is ever likely to be, because they do not take into account one basic fact, namely, that the movement of the light can be controlled by volition. This can be demonstrated by practically everyone for themselves; nevertheless, for some unknown reason, it has apparently never been discussed in the literature or taken into account in formulating a theory. Perhaps it has never previously been noticed.

An even more conclusive argument is provided by group auto-kinesis, in which a group of observers, on being informed that the light is moving, say, upwards, will almost all see it doing so, although, of course, it is stationary. In this case the difficulties in presenting a physiological solution are virtually insurmountable, yet the single fact that each observer is led to believe that the light is moving upwards is sufficient basis to account for each observer actually seeing it doing so.
There is a scientific principle known as Occam's Razor, which states, in effect, that if a single theory can explain a situation, then any hypothesis based on a multiplicity of ad hoc theories is invalid. When the principle of Occam's Razor is applied to the materialist and dualist theories of perception, there is little doubt, based on the foregoing examples, about which theory it rejects. In these circumstances, the materialist contention that all conscious phenomena are organic, but they are not explicable because the brain is too complex to understand, is no longer valid.

The 'idea-pattern' theory of consciousness is able to accommodate many of the anomalies of perception. For example, why is it that in the whole field of vision, a rotating anemometer is the only object which can be affected by volition? With auto-kinesis, why must the room be in total darkness for volition to be effective, whilst the anemometer effect can be observed in full daylight? Although Tyrrell suggested that perceptual images could be initiated by a psychological source additional to sensory data, there is ample evidence indicating that they can be initiated and controlled by at least five different agencies, namely, a pattern in the visual cortex, volition, suggestion, hypnosis and, more speculatively, telepathy. All these result in the creation of a belief or idea in the consciousness. Whichever of these is the dominant factor in any set of circumstances controls perception. Under normal conditions the dominant agent is sensory data and this has no doubt been established through evolution. Throughout evolutionary existence, consciousness has learned to create a specific image from a specific brain pattern. Repeated observation during this period has firmly established in consciousness the appropriate responses to the retinal signals, with the result that volition cannot affect them.

However, consciousness is sometimes presented with brain patterns to which it has no established response, because they have never, or extremely rarely, arisen in the past. Examples are a specifically designed object rotating in the line of sight at a suitable speed, such as an anemometer, or the behaviour of a dim light in total darkness.

It will now be seen why an anemometer, or rotating radar scanner, is the only area in a field of vision which can be controlled by volition. Whereas the perceived background initiated by the cerebral pattern is a firmly a recognized response. It is therefore more susceptible to other influence, and when volition engenders a belief that rotation is actually in the opposite direction, the image is created accordingly.

It can also be shown why controlled auto-kinesis must be carried out in total darkness. If there is sufficient general lighting to relate the dim light to the background, the luminous point becomes part of the general background and subject to its dominant influence. There is nothing to suggest that once an image has been created, from any source, its interpretation can be affected by volition. This would indicate that interpretation is conducted by an even higher level of consciousness, and if the creation of mental percepts is not a physiological function, as the foregoing observations strongly suggest, then it is most unlikely that there is a reversion to organic functioning in the conscious interpretation of a percept.

The hypothesis that perception is independent of the brain appears to be confirmed by several anomalies of normal vision. It would seem that perception is unaffected by the passage of time, and whilst all faculties of the brain and body deteriorate through normal ageing, perceptual images are as clear and detailed in old age as in youth. (Damage to the operation of the optical system may be caused by cataracts and retinal detachment, but these are defects which have developed at any age, and not symbols of normal ageing.) From the physiological point of view, this implies that the visual cortex itself does not age, which would make it a unique physiological phenomenon.

Again, perception does not appear to be affected by the observer's bodily condition, because it is seen to be as detailed and clear when he, or she, is suffering from high blood pressure, exhaustion, depression, nausea, etc., as when perfectly fit, yet these and similar conditions adversely affect all physiological activities.

The explanation of such situations could be that consciousness can construct fully detailed images from a minimum of cerebral information : in fact, it can obviously do so from nothing more than an idea or belief. Even if the visual cortex, due to ageing or bodily condition, is deficient or imperfect in the configuration it presents, consciousness nevertheless constructs the full image we observe. This outcome would be impossible if the ageing cortex were itself the perceptual experience, or consciousness were directly dependent on it.

A readily observable aspect of this phenomenon is the fact that the field of vision does not include a blank area caused by the blind spot in the eye. It has been claimed that experiments (although admittedly by no means reliable) made with computers and artificial blind spots suggest that the brain performs some kind of unspecified compensatory adjustment to fill the blank area, but it is far more likely that, in line with the phenomena already described, consciousness is able, with sufficient information from the blind spot fringes, simply to fill the details of the image it has created.

Again, it would appear from observed behaviour that everybody looking at the same object has an identical perceptual image (apart, of course, from parallax and spatial position). On the other hand, each individual is totally different from everyone else. He or she would walk differently, talk differently, eat, sing, write, breathe, digest, think and so on with all the physiological functions; and people could individually be of any size, race, sex, age, colour, etc., yet, nevertheless, they would all have identical perceptual activity.

The hypothesis that perceptual activities do not deteriorate with the passage of time is supported to a remarkable extent by the phenomenon of regression under hypnosis. In this state, a middle-aged subject is, for example, apparently able to re-experience in absolute detail an experience of his youth. In doing so, he adopts all the characteristics he had at that time — posture, voice, phraseology, handwriting, personal idiosyncrasies, etc.—in a way completely impossible for it to be due to memory. If an experience can be retained unchanged in the consciousness for half a century, and that stratum of consciousness is also able to create percepts with unchanged clarity and detail throughout the same period, it is virtually impossible to avoid the conclusion that it is a non-physiological situation. A simple test which might clarify the claims of regression, one way or the other, was given in the July issue of the Journal (Roberts, 1991).

It may seem unnecessary to give any further examples illustrating the probable non-physiological nature of consciousness, and especially its apparent independence of physical time, but a reference to time distortion under hypnosis is appropriate. This is a phenomenon in which a hypnotised subject is able to undertake mental feats normally requiring a considerable time in an almost impossibly short time. Investigators of the highest standard (Cooper & Erickson, 1951; Cooper, 1952) came to the conclusion that with a suitably hypnotised subject the amount of mental effort which could be undertaken, or hallucination experienced, in the subjective period of duration, was "greatly in excess of what the worldly time interval would ordinarily permit". A typical example cited by Cheek and LeCron (1968) was that of a child who could watch an hour's television programme and re-experience it in fullest detail in a few seconds. The veracity of this situation has been confirmed by many different experiments and observations, and it demonstrates two qualities of consciousness, firstly, that it is virtually impossible for a physical brain to operate at such speeds and, secondly, that there would certainly appear to be a stratum of consciousness operating apart from physical time.

It would seem that what has now to be given serious consideration is that there is a stratum of consciousness independent of the brain, unaffected by the passage of time, which retains a complete record of experiences passed into it and which allows such experiences to be extracted and re-experienced at a later date, and within which perception functions in exactly the same manner in everybody who is normal, irrespective of all differences in their physical attributes, or temporary changes in bodily condition. All this indicates that there is some kind of common factor throughout consciousness in the whole of humanity and that this common factor is not limited by physical constraints.

What does this hold for parapsychology, or at least for its mental phenomena? Front now on, we can only speculate, but on good grounds. A non-physiological element in consciousness will have no problem connected with physical distance. For example, with a crisis apparition, where the agent might be several thousand miles away, one big objection to accepting its veracity has been the difficulty of the transmission of the necessary information. However, if the question of distance does not arise, there is no difficulty in accepting that one person's consciousness is not prevented by intervening distance from becoming aware of the experiences of another, especially if, as indicated above, some common factor pervades the consciousness of the whole of humanity.

This situation puts telepathy in a different perspective. Theories to explain telepathy have tended to assume that it has a physical quality in that some unknown kind of radiation must be involved, but this approach is invalid. Not only is it ruled out by the inverse square law, but no sign of any transmitting or receiving organ in the brain has ever been found. This fact alone has been sufficient for many investigators to reject the possibility of telepathy, yet such objections have no foundation when it is recognized that a stratum of consciousness may be non-physical.

As a result of this situation, it is interesting, and justifiable, to consider the possible role of timeless perception in parapsychology. If perceptual experience and its relevant stratum of consciousness are not affected by the passage of time, what happens when the associated brain dies? Is there any reason why it, too, should cease to exist? If it is non-physical, it should be immune from the effects of normal physical agents causing death and decay, and should continue to exist.

Since consciousness can make its influence apparent only through the highly complex organic structure of the brain, it would appear that a disembodied consciousness, if it could exist, would be an isolated and impotent entity. However, it is always possible that it could behave as if it were a telepathic agent, similar to its pre-death state, and could utilise the cerebral facilities of an existing alternative consciousness. There are innumerable anecdotal accounts of communication in various forms with a disembodied consciousness, and there is now good ground for giving them some attention.

These are some of the considerations which arise if consciousness contains a stratum independent of the brain. There is, of course, no proof of anything parapsychological in the foregoing; in fact, the very nature of consciousness itself could well preclude any such conclusion. However, the volume of circumstantial evidence concerning so many different aspects of consciousness is so formidable that, unless it can be disproved, acceptance of a non-physical element cannot be avoided. It will be appreciated that the foregoing account does not attempt to explain in detail any parapsychological phenomenon; what it does do is to try and show that there is a solid foundation, based on scientifically-grounded observations, on which future investigations into this aspect of parapsychology can be carried out with confidence.

Ashford, Kindlestown Hill
Delgany, Co. Wicklow

- Cheek, D. B. and LeCron, L. M. (1968) Clinical Hypnotherapy. New York: Grime Sc Stratton.

- Cooper, L. F. (1952) Time distortion in hypnosis. In LeCron, L. M. (ed.) Experimental Hypnosis. New York : Citadel Press.

- Cooper, L. F. and Erickson, M. H. (1952) Time distortion in hypnosis II. In LeCron, L. M. (ed.) Experimental Hypnosis. New York: Citadel Press.

- Roberts, F. S. (1991) Some apparently non-cerebral aspects of consciousness. JSPR 58, 31-38.

- Tyrrell, G. N. M. (1953) Apparitions. London: S.P.R./Duckworth.