Thursday, December 23, 2010

Visual Experience/Structure in Near Death Experiences

Thomas Droulez

Judging by what people who had NDEs with clear visual aspects frequently report (including congenitally blind people, which is very disturbing and interesting, since it might tell us a lot about the functional role of the eyes and the impossibility to equate the visual field –or visual screen, to use the words used by John Smythies in his analogical functional description- and the retinal surfaces in the eyeballs –the optic lens, in his description-…. About the topic of congenitally blind people able to accurately retrieve visual information during NDEs, cf: Ring and Cooper’s excellent study… but that may be too long to develop here and now), they were able to “see through” objects (as weird as it may sounds!) and they had no limitations in their visual field (for example: no ocular rivalry any more, and no blurring!)

About the curvature of their visual field during NDEs, I do not know if we can say that it is really curved in itself, or if it phenomenologically appears as being curved, or if speaking of a “bubble” or a “spherical” form was only the verbal rendering of the experience that was the closest to what they actually experienced (they also speak of a total “omnidirectional” visual perception). If I remember well, in my description I used the terms “as if” (or something of that kind) in my first comment about visual perception during NDEs, when I was describing the subjects’ visual impressions during their anomalous near-death experiences. Some of these subjects describe it (verbally) in retrospect (perhaps because they have to use commonly shared usual frames of reference and commonly intelligible words to describe their anomalous near-death perceptual experience) as being a situation in which they (as observers) suddenly seem to be not “within” but on or rather into the surface of a spherical unit, but with no hidden parts.

It is as if they were now the surface of that sphere itself that is able to expand and contain the “external” environment. Judging by the reports, and especially those studied by Jean-Pierre, the subjects who experienced anomalous but veridical visual perceptions (for example: being able to reach distant or previously unknown places and see events happen that were later reported to have truly happened, or being able to see “through” walls or various obstacles hidden or forlorn objects the existence and aspect of which was later confirmed by people belonging to the hospital medical staff, etc) during an NDE cannot be described as static observers within a dynamically expanding/retracting spherical envelope: it would be more apt to say that it was as if they were that envelope/surface itself, because they did not have any more to revolve around an object to be able to get an overview of all its profiles at various angles, but this visual overview was presented as a unified and simultaneous view of all these profiles (I readily admit that I cannot imagine what it looks like, but maybe we can reach some understanding of that and an approximated representation of it by imagining that it would be the (higher-dimensional?) equivalent of the passage from a succession of 2D visual profiles of an object to a 3D visual presentation of that object.

The people who were able to sufficiently focus their attention on their visual experience and who later thought about the best verbal means to convey the essence of that peculiar perceptual experience, reported that, during their NDE, they were able to see the objects “entirely” as a synchronistical “multi-angle” perspective (and not as our classic/usual diachronically constructed succession of isolated visual profiles of the object with a final amodal completion of its successively hidden profiles).

We must be cautious. I think that, in a way, some of them spoke about a “spherical” or “bubble” impression mainly because of three inter-individually recurring aspects of the experience : 1/ they were able to have a 160° visual field and in some cases there are reports of a 360° visual panorama (I cannot spontaneously remember of any specific observation about the curvature, but I will check in the literature); 2/ they had a peculiar new ability of “projection” or “zooming” (both competing –motor and visual- interpretations of this ability exist) at multi-angle perspectives (as if they were the surface itself of a volume containing a lower space) to see distant places or microscopic details of their spatial environment; 3/they sometimes had peculiar “weightless” (bodily?) sensations (that’s why there are sometimes expressions in their reports like –these are not quotes, only typical samples- “I felt like a floating soap bubble” or “it was as if I was hovering above the room and I was a round cloud”: sometimes, when they think they have an “aerial body” (one of Jean-Pierre’s subjects used that expression), then they become suddenly able to locate their limbs in a kind of new reconstructed body image, but when they stop thinking that they have a body (to be more accurate: when they stop being convinced that since they are not “nothing” and they still exist as “observers” they must logically have a kind of embodiment similar to what we are used to), then they begin to feel either like a medium-sized “spherical” cloud or (less frequently reported) like a mere shrunken “point”. I am not sure to know if it tells us something about the structure of their visual “zooming” and “spreading” ability or rather about their possible new kind of embodiment…

Maybe Bill Rosar's suggestion (stated in "On Looking vs. Being Curved") about the curvature being due to the structure of the eyeballs is interesting and relevant: couldn’t it be compatible with John’s model in which (in the camera comparison) the eyes are described as being only the lenses of our optical system (so maybe: if you change the detecting device, the lenses in our analogical comparison, without modifying the screen itself, then the latter will not appear any more as a curved surface). Maybe that is what happens in NDEs: the eyes are now out of order (or never were functional, like in the cases of congenitally blind people!) and there is a whole new structure doing their job of detection and transmission…and that’s why the new “medium” induces drastic modifications of the visual field (the “screen” part of our device)?

Tuesday, December 21, 2010

Looking Curved vs. Being Curved

It seems best to start a new thread to continue the discussion that Bob French and I have been having lately on "Neurobabble in High Places" regarding how one relates our obvious ability to see things as curved (or straight) in the visual world, yet the postulated curvature of visual space is apparently not experienced as a curved visual world. My "diagnosis" is that in order to explain this apparent paradox we need to retrace the epistemological development of the idea of curved space, which does *not* appear to have been derived from visual experience (I believe Gauss is now credited with first advancing the notion of non-Euclidean geometries that would violate Euclid's postulate about parallel lines never converging).

In works I have read on the philosophy of space and time (Mach, Poincare, Nicod, Reichenbach, Gr├╝nbaum, and Nerlich) it has never been quite clear to me how a curved space would be perceived, particularly, how curved physical space would be perceived, except for the claim that it is locally Euclidean and therefore is perceived as being flat (ergo, "locally" Euclidean). But in the case of visual space, we perceive its entirety, not just a local region of it, so logically, we should be able to perceive its curvature. Yet most of the arguments for visual space being curved, as I have previously noted, seem not to be based on the perception of curvature, but upon discrepancies between perceived straightness (or parallelness) and third person observations of the test display stimuli employed to make those judgments (the so-called "alley experiments" originated by Blumenthal).

As geometrodynamics points out, physical space(-time) is curved because of a physical force: gravitiy. Why is visual space curved, moreover, of variable curvature as has been claimed by Bob, Indow, Koenderink et al? Is it attributable to the sphericity of the eyes themselves which, to some extent might introduce variable curvature as the eyes are deformed as they are turned?

In this regard, I was particularly interested in the NDE reports which Thomas Droulez shared from the research of Jean-Pierre Jourdan. I was particularly struck that patients reported something like an expanding bubble--this pointing to some sort of sphericality of visual space--and that the visual world as (apparently) seen from outside (from the vantage point of a "5th dimension") itself seemed to involve a kind of spherical construction as well. Perhaps Thomas or Jean-Pierre could supply more details of this apparent structure?

Sunday, December 5, 2010

Neurobabble in high places and other topics.

Here are some comments, that seem appropriate for this blog, on the new book by Stephen Hawking and Leonard Mlodinow “The Grand Design” (New York, Bantam, 2010). (My comments in square brackets)
Key words to be queried starred in text.

They say:

“Recent experiments in neuroscience support the view that it is our physical brain, following the known laws of science, that determines our actions, and not some agency that exists outside these laws.” (p. 32)

[This represents a total misreading of these "recent experiments" in which NCCs are illegitimately identified with phenomenal events. Also we determine our consciously motivated actions—not our brains]

“…we human beings…are ourselves mere collections of fundamental particles of nature…” (p. 181)

[ How does he know that?]

“…the raw data sent to the brain are like a badly pixilated picture with a a hole in it [the blind spot]. Fortunately the human brain *processes* that data, combining the input from both eyes, filling in gaps on the *assumption* that the visual properties of neighboring locations are similar and interpolating. Moreover, it reads a two-dimensional array of data from the retina and creates from it the *impression* of a three-dimensional space. The brain, in other words, builds a *mental picture* or model.” (pp. 46-47).

“…our brains *interpret* the input from our sensory organs by making a *model* of the outside world. We form *mental concepts* of our home, trees, other people, the lectricity that flows from wall sockets, atoms, molecules, and other universes. These *mental concept*s are the only reality we can know [no mental percepts?]. There is no model-independent test of reality.”

[These "mental" pictures and "mental" concepts suddenly appear from nowhere!!]

“Feynman realized that…a particle [going from A to B] takes every possible path connecting these points, and take them all simultaneously.” (p. 75). In two slit experiments this is“…how the particle acquires the *information* about which slits are open.” (p. 76)

[Particles acquiring information??]

[I should like to see Bill’s and Ray’s opinion on all this!]


Problems about higher dimensions

“…if a theory called the holographic principle is correct, we and our four-dimensional world may be shadows on the boundary of a larger five-dimensional space-time.” (p. 44)

[Nowhere does Hawking mention this idea again.]

“Similarly, we know our universe exhibits three large space dimensions” although “… the number of large space dimensions is not fixed by any law of physics.” (p.141)

[That's useful to know]

“There seems to be a vast landscape of possible universes.” (p. 144)

{Hawking assumes a priori that all higher-dimensional space-times must contain matter like ours]

“Although Einstein’s general theory of relativity unified space and time as space-time and involved a certain mixing of space and time, time was still different from space…In the early universe there were effectively four dimensions of space and none of time.” (p. 134)

Needs further explication—mixing?

Saturday, December 4, 2010

On Perceptual Reality

The earliest reference I can find to the phrase "perceptual reality" is in English statistician Karl Pearson's "Grammar of Science" (1892):

[The Motion of bodies] is not a reality of perception, but is the conceptual manner in which we represent the mode of perception which consists in the combination of Space with Time, by which mode we describe changes in groups of sense impressions; the perceptual reality is the complexity and variety of sense impressions.
Psychologists studying perception today would consider this rationalistic nonsense, and that it is rather the case that we literally see motion, first and foremost, and it is only the concept that comes afterward, based on the perception.

Perhaps we might try to seek some sort of consensus at this point and see where it takes us. Here is a general proposition:

Reality is achieved within the perceptual world.