12 January 2007

Gibt es eine Seele?

Ich bin zufällig über einen Artikel gestolpert, der sich mit genau dieser Frage befasst. Der Autor bringt eine ganze Reihe von Beispielen von Verletzungen und/oder Krankheiten des Gehirns, die zu schwerwiegenden Persönlichkeitsveränderungen führen und alle zusammengenommen sehr stark dafür sprechen, dass es keine vom Körper unabhängige Seele gibt, sondern all das, was manche einer Seele an Eigenschaften zuschreiben, in Wirklichkeit Eigenschaften des Gehirns selbst sind.

Die Fallbeispiele von Gehirnverletzungen sind teilweise echt harter Stoff, kaum vorstellbar, dass so etwas möglich ist.
In light of the above evidence, advocates of [brain-soul] dualism must now explain how the doctrine of the soul is sustainable. With these case studies, I have strived to show that the three basic aspects of consciousness - identity, personality, and behavior - are in all respects unified with the brain, and can be altered or disabled by damage to the brain. Brain damage can fragment the fragile boundaries of the self, splitting a single individual into non-overlapping spheres of consciousness that perceive and desire completely different things, or shattering the continuous thread of awareness into a multitude of fleeting selves cut off from themselves and from external reality. Changes to the physical structure of the brain can exert dramatic effects on personality, turning a friendly, hard-working, dedicated individual into a vulgar, abusive, lazy and reckless scoundrel. Conditions that affect the chemistry of the brain can entirely control behavior, robbing an individual of the ability to act or denying them the ability to stop themselves from doing so.
However, these cases constitute strong evidence against most varieties of brain-soul dualism. After all, most theists hold that the total destruction of the brain upon the death of the body will have no effect on the soul: how then can the destruction or alteration of small parts of the brain during life have such a dramatic and profound effect on it? Once we acknowledge that the brain mediates and controls all the aspects of consciousness to an overriding degree, what then do we even need to postulate a soul for?
Die Erklärung von "religiösen Gefühlen" ist dagegen eher witzig: Sie könnten nach der Aussage des Autors die Folge von kleinen elektrischen "Fehlzündungen" im Temporallappen des Gehirns sein. Es gibt Epileptiker, bei denen diese Hirnregion betroffen ist, und zu ihrem Krankheitsbild gehört, dass sie hyperreligiös sind und behaupten, Gott selbst wäre bei ihnen oder würde mit ihnen sprechen etc. Es könnte also durchaus sein, dass diese Epileptiker nur die Spitze des Eisbergs sind und abgeschwächte Fälle zwar keine "echten" epileptischen Anfälle haben, aber eben diese kleineren Entladungen, die die Betroffenen dann als "Gotteserfahrung" interpretieren.
We can make other predictions from this hypothesis. The temporal lobes contain projections to all the sensory areas - vision, hearing, taste and smell, even the vestibular regions (the sense of balance). The most intense TLTs [temporal lobe transients] could potentially spread into these regions, producing vivid sensory hallucinations - the affected individuals might see bright, shining forms and landscapes, hear voices, experience a sense of floating or flying, or experience all of these at once, depending on where in the temporal lobes the electrical instability occurs and how far it spreads. These symptoms often occur in temporal lobe epilepsy. Milder TLTs, such as the kind that occur in most people, would not produce these experiences, but would be more subtle and abstract. Depending on their extent, some might be "mild cosmic highs, the kind we feel in the early morning hours when a hidden truth becomes sudden knowledge. Other more intense transients would evoke the peak experiences of life and determine it thereafter. They would involve religious conversions, rededications, and personal communions with God" (Persinger 1987, p. 16). Like all TLTs, they would be followed by marked reductions in anxiety and positive expectations for the future. In any case, there is no fundamental difference between the seizures of temporal lobe epileptics and the temporal lobe transients experienced by ordinary people - the difference is a matter of degree, not of kind.

"What would happen to the patient's personality - especially his spiritual leanings - if we removed a chunk of his temporal lobe? .... Would he suddenly stop having mystical experiences and become an atheist or an agnostic? Would we have performed a 'Godectomy'?" (Ramachandran 1998, p. 187)
Empirical support for this hypothesis comes in the form of experiments conducted by Dr. Persinger himself. We cannot predict natural temporal lobe transients, so it is difficult to precisely measure their effects - but what if we could produce artificial ones on demand?
This is exactly what Dr. Persinger has done, by constructing what some have dubbed the "God helmet". It is an ordinary motorcycle helmet fitted with solenoids which, when worn, produce a complex magnetic field designed to interact with and stimulate the temporal lobes of the brain. Four out of five people who undergo this experience report sensing a "presence" in the room with them, one which religious individuals frequently identify as that of God (Holmes 2001, p. 28).
Indeed, such a situation can happen naturally. Alzheimer's disease, for example, tends to attack and damage the limbic system early on - and therefore it can be no coincidence that loss of religious interest is a frequent symptom of its onset (Holmes 2001, p. 27). Why would God create and then inflict on people a disease that robs them of the ability to hear and respond to him? Would such an individual be punished for nonbelief upon their death?


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