General Articles 1

The direct realist theory of perception states that we are directly aware of external physical objects. This was a view supported by many 20^th century philosophers. Its main opponent was the scientific representative theory in which phenomenal objects and their space are creations of the central nervous system. The article claims that recent experiments, notably Smythies &Ramachandran (1998), (1) Ramachandran and Blakeslee (1998), (2) Kovacs et al (1996) (3) and Yarrow et al (2001) (4) resolve the controversy in favour of the scientific representative theory.
 
Thus perception is the end result of a probability based computation. The previous direct realist theory held that the objects experienced only existed externally, but under scientific representative theory, they have to have their own phenomenal space. This is related to the fact that knowledge and experience of things are seen to be different in modern neuroscience. Thus in agnosia there is normal vision without knowledge about the objects seen, while in blindsight there is knowledge with consciousness. The same applies to awareness of the body, where phenomena such as phantom limbs demonstrate that the model of the body constructed by the brain may be different from the external reality. It is suggested that phenomenal space and physical space are different, they may be causally related but external to one another.

References:-

(1)  Smythies J. & Ramachandran V,  An empirical refutation of the Direct Realist Theory of Perception  Inquiry 40 pp 437-8

(2)  Ramachandran & Blakeslee,  Phantoms in the Brain  (1998)

(3)  Kovacs et al, When the brain changes its mind  Proceedings of the National Academy of Sciences USA 93 pp. 508-11

(4)  Yarrow K. et al  Illusory perceptions of space and time  Nature 414 pp 302-5

In discussions of blindsight, the conventional assumption has been that visual discrimination was preserved by using another non-conscious route that avoided the damaged visual cortex. Attempts have made to disprove this assumption, but the authors seek to defend the original view. The critics had suggested that blindsight was just a degraded version of normal vision, and that it was based on islands of functioning cortex within a damaged striate cortex, rather than a separate undamaged pathway. If this could be shown to be the case, it would appear to remove the threat to the mainstream reductionist stance on consciousness.

The first argument may be that the subject is biased against reporting a visual stimuli. However, the two alternate forced-choice task, where the subject has no separate knowledge of the right answer gets round this particular objection (Azzopardi & Cowey, 1997)⁽¹⁾. Studies showed that in normal subjects, the same mechanisms subserved conscious reports and forced-choice discrimination, while in subjects with damaged cortex the mechanisms were different. A later study (Kentridge et al, 1999)⁽²⁾ showed that there were differences between the good hemisphere of the brain and the damaged hemisphere in a blindsight subject used in the previous study by Azzopardi. A neuroimaging study by Stoerig et al (1998)⁽³⁾ on a blindsight patient showed no response to visual stimuli in the damaged cortex but activity in the extrastriate cortex, which did not contain the normal pathway. They did not find elements of portions of surviving functional cortex in the striate. Fendrich et al, (1992)⁽⁴⁾ did find such evidence, but it does not appear to have been enough to support extensive residual vision. The studies suggest to the authors that visual consciousness depends on an intact striate cortex, but detection and discrimination do not. Some studies do show that blindsighters have some degree of conscious awareness of movement or flickering from a stationary light source, but this does not disprove that the basic blindsight discrimination of stationary objects is suggested by recent studies to use a different pathway from conscious awareness.

References:-

(1)  Azzopardi, P & Cowey, A (1997)  Is blindsight like normal near-threshold vision?  Proceedings of the National Academy of Sciences USA, 94, pp. 14190-4

(2)  Kentridge, R., Heywood, C. & Weiskrantz, L. (1999)  Effects of temporal cueing on residual visual discrimination in blindsight  Neurpphysiologia, 37, pp. 479-85

(3)  Stoerig et al (1998)  Magnetic resonance imaging of a blindsight patient  Neuroreport, 9, pp. 21-5

(4)  Fendrich et al, 1992  Residual vision in a scotoma: Implications for Blindisight  Science, 258, pp. 1489-91

Block, N. (1995)  On a confusion about a function of consciousness  Behavioural and Brain Sciences, 18, pp. 227-87

Holt, J. (1999)  The use of blindsight in debates about qualia  Journal of Consciousness Studies, 6 (5), pp. 54-71

Marzi, C. (1999)  Why is blindsight blind?  Journal of Consciousness Studies, 6 (5), pp. 12-18

Pribram, K. (1999)  Brain and the composition of conscious experience  Journal of Consciousness Studies, 6, (5), pp. 12-18

Riddoch, G. (1917)  Dissociation of visual perceptions  Brain, 40, pp. 15-57

Sahraie, A. & Weiskrantz, L. (1997)  Conscious and unconscious processing of visual signals  Proceedings of the National Academy of Science USA, 94, pp. 9406-11

Stoerig, P. & Cowey, A. (1997)  Blindsight in man and monkey  Brain, 120, pp. 535-59

Weiskrantz, L. (1986)  Blindsight: A case study and implications  Oxford University Press

Weiskrantz, L. (1997)  Consciousness Lost and Found  Oxford University Press

Zeki & ffytche, D. (1998)  The Riddoch syndrome  Brain, 121, pp. 25-45

Sanders, M. & Weiskrantz, L. (1974)  “Blindsight”: Vision in a field defect





Jason Holt

University of Manitoba

Blindsight in debates about qualia

Journal of Consciousness Studies, 6, No. 5, 1999 pp. 54-71

Franck concentrates on the question of the relationship between time and in particular the connection between consciousness and the present time. He says that there is no concept of the present in either quantum theory or relativity. In these theories, there is no part of the universe that is marked out from the rest as being the present. The criticism of this approach is that in ignoring the present, science ignores consciousness. For humans as conscious beings, everything that we know to exist makes itself known through conscious awareness at the present moment.

 Franck also discusses memory in relation to consciousness and the concept of the present. Temporal change means that situations that had been in the future become present situations and then become past situations. The existence of memory allows humans to distinguish between the present and the past. Franck suggests that it is consciousness which creates the concept of the present, because not withstanding the ability to remember the past and speculate about the future, direct conscious perception and experience is focused on a single point in time, and it is not clear that such a thing as the present would exist without consciousness. Franck differentiates between direct perception and experience on the one hand and conscious thinking and memory on the other. he takes this to be the distinction between the temporally changing external world and the thoughts and reflections of the brain itself.

Franck considers the question of perception, which presents in a single state and yet is never in the same state. He views anything which is perceived as being singled out from the many possibilities of the state vector, and then brought into the present. This is only for a moment and each moment another state is manifested. On this basis, the flow of the time comprises states that appear in the present and then vanish into the past. Energy inputs into the brain are sensory information that produces perception, but this functions in such a way as to seem to be out there rather than in the brain.

In memory, the original perceptions are reactualised. The memory structure that performs the reactualisation and the original perception are separated in time. The two states are drawing on separate information, the original external input in one case and the stored memory in the other. However, the feel of the perception is different. The initial perception is much more concrete than the memory. The creation of memories demands energy. In perception, the energy comes directly from the environment, but in memory this link has been interrupted. This is reflected in their different feel in consciousness. In the original perception, one of the alternatives within the vector was selected to actually happen. Original perceptions are separated from subsequent recreation in memory by time. In one respect this is conventional physical time as measured by clocks. However, this is not the only difference. There is also the difference of the less substantial experience provided by memory, as against the original perception.
 
Franck attempts to explain this difference in terms of quantum theory. Each state entering the brain system contributes a weighting to the probabilities which may later be actualised as an experience of the present moment. Actualisation in the present means that the probability of a particular experience has moved from less than unity to unity. This temporal flow, with states being brought into the present is distinguished from time in the real world outside the brain. The present moment is argued to persist for ever, but the states manifesting in the present are constantly changing. The idea of the flow of time is something wholly derived from conscious experience. There is a modern distinction between the time of physics measured by clocks and subjective time as it is experienced. The experience of ‘now’ or the present moment is indistinguishable from the conscious experience as a whole. Consciousness is conceived to be about something and there is a problem in separating it from its own contents. Husserl is quoted as having concentrated attention on the relative motion between consciousness and the presence of consciousness. He could look at it from the point of view of a ‘now’ at rest while events passed by or ‘now’ passing events that were at rest. However, he never appeared to have resolved this distinction.
 
It is pointed out that in Heideger and much Eastern philosophy this distinction becomes less of a problem, because of the idea that being or consciousness can ultimately be separated from the entities that form the contents of consciousness. This attitude allows consciousness as such to come to the fore. It is this pure consciousness of ‘being’ stripped of the clutter of the contents of consciousness that is missing from physics.
 
The author suggests that content-free consciousness is a pure state of the mental world, while the quantum wave is a pure state of the physical world. He sees these both as symmetries when either the mental world is actualised by an experience, or when a particular physical state is selected from the quantum range of probabilities.

References:-

Bergson, Henri (1889)  Time and free will   Harper

Del Giudici et al (1988)   Vacuum evolution   Physics Letters, B 206, 661-664

Franck, Georg (2000)   Time and presence   in, Science and the Primacy of Consciousness   The Noetic Press

Franck, Georg (2001)   Time, actuality, novelty and history   in, Life and Motion of socio-economic units   Taylor and Francis

Franck, Georg (2003)   How time passes   in, The nature of time   Kluwer Academic Publishers

Globus, Gordon (2003)   Quantum closures and disclosures   John Benjamins

Heidegger, Martin (1927)   Being and time   Harper & Row

Husserl, Edmund (1966)  The phenomenology of internal time consciousness   Indiana UP

Jibu, Mari & Kunio Yasue (1995)   Quantum Brain Dynamics and Consciousness

Pauli, Wolfgang (1994)   Writings on physics and philosophy   Springer

Pöppel, Ernst (1997)   The brain’s way to create nowness   ed, H. Atmanspacher..in, Time, temporality, now   Springer

Pribram, Karl (1991)   Brain and perception   Lawrence Erlbaum

Stapp, Henry (1993)   Mind, Matter and Quantum Mechanics  Springer

Umezawa, Henry (1993)   Advanced field theory: Micro, Macro and Thermal Physics   American Institute of Physics

Vitellio, Giuseppi (1995)   Dissipation and memory capacity in the quantum brain model   John Benjamins

Vitellio, Giuseppi (2001)   My double unveiled: The dissipative quantum model of the brain   John Benjamins

Vitellio, Giuseppi (2002)   Dissipative quantum brain dynamics   ed. No matter, never mind   John Benjamins

Vitellio, Giuseppi (2003)   Classical chaotic trajectories in quantum field theory

The author looks at human thought processes with particular reference to the ideas of David Bohm. Bohm is indicated to have thought that while logical thought was important for the scientific effort, it might be a subset of more general thought processing, just as classical physics can be seen as a subset of quantum physics. Bohm considered that the basic thinking process was not logical. This was why new ideas could appear suddenly, often after a long period of unsuccesful but more logical work. He saw this as analogous to the quantum jump. Thus there might be a quantum-like general thinking process, which at a later stage has to be justified by more logical processes. Bohm thought it likely that quantum processes were involved in cognition, and that this accounted for the quantum-like nature of a lot of cognition. While most brain processes were admitted to be describable by classical physics, Bohm thought that there might be certain areas that were so finely balanced as to be described quantum mechanically. Further, in some altered states of consciousness, classical processes might play only a minor part, and this would allow holistic features to predominate.

References:-

Bohm, D. (1951)    Quantum Theory    Prentice-Hall  Reprinted: Dover science books

Bohm, D. (1980)    Wholeness and the Implicate Order    Routledge

Bohm, D. (1990)    A new theory of the relation of mind and matter    Philosophical Psychology, 3 (2), 271-286

Bohm, D. & Hiley, B. (1993)    The Undivided Universe

Fodor, J. & Pylyshyn, Z. (1988)    Connectionism and cognitive architecture  In Pinker, S. & Mehler, J. Eds.  Connections and Symbols, pp. 3-71    MIT Press

Globus, G. (1995)    The Postmodern Brain    John Benjamins

Globus, G. (2003)   Quantum closures and disclosures    John Benjamins

Hiley, B. (2004)    Information quantum theory and the brain    In Globus, G., Pribram, K. & Vitiello, G. eds.  Brain and Being    John Benjamins

Husserl, E. (1913/1976)    General Introduction to Pure Phenomenology    George Allen & Unwin

Penrose, R. (1994)    Shadows of the Mind    Oxford University Press

Plotnitsky, A. (2002)    After Bohr and Derrida    Duke University Press

Pylkkänen, P. & Vaden, T. Eds. (2001)    Dimensions of Consciousness    John Benjamins

Smolensky, P. (1988)    On the proper treatment of connectionism    Behavioural and Brain Sciences

Strawson, P. (1966)    Essay on Kant’s Critique of Pure Reason    Routledge

Van Loocke, P. Ed. (2001)    The Physical Nature of Consciousness    John Benjamins

Vitiello, G. (2001)    My Double Unveiled    John Benjamins

Atmanspacher starts his article by stressing that the randomness inherent in quantum theory is in sharp contrast to the determinism that permeates classical physics. This randomness is a fundamental characteristic of the theory, not a result of ignorance of the full system, as is the case in statistical mechanics.

Atmanspacher is also careful to draw a clear distinction between correlation and cause and effect. When two effects are correlated, one effect may cause the other, but equally well it may not, with the correlation being due to third cause lying in the common history of the two effects. He points out that while causation explains why something happens, correlation does not of itself explain why either of the correlated effects happen. Thus the fact that certain brain areas or functions are activated during consciousness does not necessarily explain what causes consciousness.

Atmanspacher discusses the ideas of the physicist, Henry Stapp. Stapp’s ideas on quantum theory are quite close to the Copenhagen interpretation, with major importance attached to the distinction between the observer and the observed. Stapp places the divide between observer and observed in the brain, and thinks that consciousness can influence brain activity.

The article gives some prominence to Beck and Eccles. They have done detailed work on possible quantum level information transfer at the synapses, involving electron transfer between biomolecules, but they have not provided a link from this to consciousness.

Atmanspacher appears relatively sympathetic to the Penrose/Hameroff model, which is unusual in consciousness studies. He comments that Hameroff’s microtubule theory is the lowest physical level at which a quantum consciousness theory has been attempted, with other theories implemented somewhere between synaptic and neuronal assembly level.

The article explains that the Penrose’s thinking derives from the Gödel theorem, and his interpretation of the theorem, which is that there is some non-computable function in the human brain. This latter is realised by a gravitationally based reduction of the wave function. Atmanspracher points out that in contrast to other quantum theories of consciousness, such as Stapp, Penrose is proposing an alteration to the presently agreed quantum theory. Hameroff has provided the physical position in the brain for the implementation of this theory. He suggests that the microtubules within the neurons might be a suitable location, because they might be screened from the environment to support quantum coherence for a sufficient period of time.

Atmanspracher, who is much more open minded than most commentators on consciousness does, nevertheless, fall into the old habit of quoting the critics of the model without quoting Hameroff’s response. Thus he mentions Tegmark’s objections to the theory based on the speed of decoherence, but not Hameroff’s criticism of Tegmark’s calculations. Similarly, the article refers to a paper by Grush and Churchland as providing an objection on philosophical grounds, but it does not explain either their objections, not mention the reply to them by Penrose and Hameroff. The last part of the section on Penrose/Hameroff also states that there are no plans for empirical confirmation of the theory, whereas Hameroff has proposed 20 possible tests, including plans to test Penrose’s theory of a gravitationally driven wave function collapse.