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Old 11-14-2002, 10:37 AM   #71
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I think the analogy works better if you use a sphere rather than a cylinder, since a sphere does not have edges - on a cylinder, there will be a central line.
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Old 11-15-2002, 08:07 AM   #72
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We can take the cylinder and fold it over to make a torus shape, which is just as good. It's too hard to make a sphere out of paper, isn't it?
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Old 11-15-2002, 12:05 PM   #73
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Actually, it's pretty hard to make a decent torus out a single piece of paper too. Still, I see your point.
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Old 11-15-2002, 09:02 PM   #74
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Quote:
Originally posted by eh:
<strong>We can take the cylinder and fold it over to make a torus shape, which is just as good. It's too hard to make a sphere out of paper, isn't it?</strong>
Simple, screw it up into a ball
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Old 11-16-2002, 07:08 AM   #75
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Don't mean to jump into the middle of an arguement, but most of you seem informed enough to answer my question: I have heard (sceince channel and whatnot; bad sources I know...) that nde's have happened in all cultures, and often reflect the mainstream beliefs of that culture, although not necessarily that of the person. For example, an atheist in Geaorgia, USA might experience a bright light and tunnel to a heaven-like place. I'm aware there are cases where peopl simply have out-od-body experiences, but I'm interested in whether or not they can be attricuted to societies influence on views of the afterlife.
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Old 11-16-2002, 09:56 AM   #76
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Yes, they can and do. I've read of some Hindu NDE's, that do not look anything at all like those in the West. It seems the only thing common for all cultures, is the feeling of peace and the light. The message is always different. A new ager and fundementalist both will claim to have met God, but apparently this deity of the afterlife suffers from multiple personality disorder.
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Old 11-16-2002, 09:57 AM   #77
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Quote:
Originally posted by crocodile deathroll:
<strong>

Simple, screw it up into a ball </strong>
Cheater!
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Old 11-16-2002, 12:21 PM   #78
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I think NDEs are more of and obsession with the new age movement that any think else and became very popular especially after <a href="http://skepdic.com/moody.html" target="_blank">Raymond Moody</a> published his book "Life after Life."
I treat the NDEs as some kind of a red herring that is no evidence of a window into the afterworld. New Agers frequently claim they see all their dead relatives, Adult Christians may commonly claim to contact with religious figures like God, Angels, the Virgin Mary, or Jesus, but children with no religious indoctrination may meet people that have not died like close relatives or they report being united the fictional characters like the the Telly Tubbys or Thamas the Tank Engine and Friends. Hardy the classical image of Heaven
The "starving brain" theory I feel is the best explanation such as depriving the brain of oxygen or anoxia.

[ November 16, 2002: Message edited by: crocodile deathroll ]</p>
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Old 11-16-2002, 03:49 PM   #79
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Quote:
Originally posted by strubenuff:
[QB]For example, an atheist in Geaorgia, USA might experience a bright light and tunnel to a heaven-like place.
Actually, the tunnel and the light are not culture-specific features of the NDE, nor are they limited to NDE's. The tunnel and light are very common with psychedelic experiences, for instance psilocybin and ketamine. As Blackmore states in her book Dying to Live, the tunnel and light "appear in a bewildering bariety of conditions and are one of the commonest forms of hallucination" (p. 67). Blackmore goes on to argue that the tunnel and light are expected consequences of over-activation of the visual cortex. On the other hand, the specific appearance of the tunnel varies very widely from person to person.

According to Susan Blackmore's article <a href="http://www.susanblackmore.co.uk/si91nde.html" target="_blank">Near-Death Experiences: In or out of the body? Skeptical Inquirer 1991, 16, 34-45</a>:

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Tunnels do not only occur near death. They are also experienced in epilepsy and migraine, when falling asleep, meditating, or just relaxing, with pressure on both eyeballs, and with certain drugs, such as LSD, psilocybin, and mescaline. I have experienced them many times myself. It is as though the whole world becomes a rushing, roaring tunnel and you are flying along it toward a bright light at the end. No doubt many readers have also been there, for surveys show that about a third of people have—like this terrified man of 28 who had just had the anesthetic for a circumcision.

I seemed to be hauled at "lightning speed" in a direct line tunnel into outer space; (not a floating sensation . . .) but like a rocket at a terrific speed. I appeared to have left my body.

In the 1930s, Heinrich Klüver, at the University of Chicago, noted four form constants in hallucinations: the tunnel, the spiral, the lattice or grating, and the cobweb. Their origin probably lies in the structure of the visual cortex, the part of the brain that processes visual information. Imagine that the outside world is mapped onto the back of the eye (on the retina), and then again in the cortex. The mathematics of this mapping (at least to a reasonable approximation) is well known.

Jack Cowan, a neurobiologist at the University of Chicago, has used this mapping to account for the tunnel (Cowan 1982). Brain activity is normally kept stable by some cells inhibiting others. Disinhibition (the reduction of this inhibitory activity) produces too much activity in the brain. This can occur near death (because of lack of oxygen) or with drugs like LSD, which interfere with inhibition. Cowan uses an analogy with fluid mechanics to argue that disinhibition will induce stripes of activity that move across the cortex. Using the mapping it can easily be shown that stripes in the cortex would appear like concentric rings or spirals in the visual world. In other words, if you have stripes in the cortex you will seem to see a tunnel-like pattern of spirals or rings.

This theory is important in showing how the structure of the brain could produce the same hallucination for everyone. However, I was dubious about the idea of these moving stripes, and also Cowan’s theory doesn’t readily explain the bright light at the center. So Tom Troscianko and I, at the University of Bristol, tried to develop a simpler theory (Blackmore and Troscianko 1989). The most obvious thing about the representation in the cortex is that there are lots of cells representing the center of the visual field but very few for the edges. This means that you can see small things very clearly in the center, but if they are out at the edges you cannot. We took just this simple fact as a starting point and used a computer to simulate what would happen when you have gradually increasing electrical noise in the visual cortex.

The computer program starts with thinly spread dots of light, mapped in the same way as the cortex, with more toward the middle and very few at the edges. Gradually the number of dots increases, mimicking the increasing noise. Now the center begins to look like a white blob and the outer edges gradually get more and more dots. And so it expands until eventually the whole screen is filled with light. The appearance is just like a dark speckly tunnel with a white light at the end, and the light grows bigger and bigger (or nearer and nearer) until it fills the whole screen. (See Figure 1.)
Blackmore references this article:

Blackmore, S. J., and T. S. Troscianko. 1989. The physiology of the tunnel. Journal of Near-Death Studies, 8:15-28.

Clearly though there are culture-, person- and situation-specific aspects of NDEs though. For instance, although 'the light' is not culture-specific, it occurs much more commonly in cases involving cardiac arrest and anesthesia.

Appearance of people or spirits or gods is fairly rare, and what is 'seen' is very variable. For instance, some have reported a female figure, some a male figure, some children have reported cats and dogs, and one Indian account of a 7 foot tall chicken. Dead relatives are the most common in adults, although as was already pointed out, children are more likely to see living friends or relatives than ones who have died (Morse, J., P. Castillo, D. Venecia, J. Milstein, and D. C. Tyler. 1986. Childhood near-death experiences. American Journal of Diseases of Children, 140:1110-1114).
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Old 11-16-2002, 09:07 PM   #80
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Comparing NDEs to death itself is like comparing a bunge jump to a suicide leap off a cliff.
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