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Charles Bonnet and Illusions of Knowledge

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In the 1970s a retired Swiss civil servant named Henri Bonnet started having hallucinations. This troubled him, a scientist by training who did not believe in the supernatural. He spoke to his grandson, Charles Bonnet, a naturalist, about this problem. Charles noted that his grandfather was able to describe these hallucinations in some detail – he reported seeing dogs and children – but he rationally understood that the things he was seeing were not real. In other words, his grandfather was presenting certain characteristics of dementia, but was well-oriented in time and space.

Charles’s interest in this odd combination of the rational and the irrational led him to explore other explanations for his grandfather’s affliction. His conclusion, reached in consultation with ophthalmologists and neurosurgeons, was that Henri’s problem originated in his eyes, and not his brain.

His grandfather previously had suffered three retinal detachments in his right eye and two in his left eye. Medical intervention had restored his eyesight, and he was able to function normally. He had no problem driving a car, for example.

A consequence of the retinal detachments was that a significant portion of each eye was no longer capable of receiving optical signals and sending these signals to his brain. About 20% of his vision was lost forever as a consequence of the retinal detachments. While Henri could see only 80% of what was in front of him, his brain, employing only the remaining 80%, had recalibrated itself to cover a full field of vision. However, Henri’s brain was confused by the fact that it received nothing from the 20% of his retinas that were no longer transmitting images. As a consequence – and this is the punch line – the brain, always trying to be helpful, made up – invented – images for his grandfather to see. The brain knew that his grandfather liked dogs and small children, so it created hallucinations of these entities to satisfy the empty part of his field of vision. Henri did not have dementia; he simply had the illusion that he was seeing something that was not there.

A parallel can be drawn with the general case of human understanding of the world. In the same way that our brains create illusions – convincing pictures – of objects that our eyes cannot see, our brains also create illusions of knowledge. These illusions, in the same way that our optical illusions derive from an absence of information, are created by our brains when we need an explanation for something but lack the information or comprehension that is required to understand it. For example, Ptolemy (and millions of others) had the illusion of knowledge that the sun orbited around the earth. Anybody who questioned this belief could be put to death for heresy. And yet this belief that was considered to be factual proved to be only an illusion.

Another example: after Europeans first traveled to the Americas, they were subject to the illusion that the human-like beings who inhabited these lands either actually were not human or were representatives of an inferior species, since there was no mention of such creatures in the Christian Bible. These illusions were considered to be facts, not theories, yet they were as fanciful as Charles Bonnet’s grandfather’s optical illusions of dogs and children. Once again, rational individuals without dementia or other organic brain disease were afflicted with illusions of knowledge – and they in turn managed to convince others that these illusions were established knowledge.

An important theme in There Are No Foreign Lands concerns these illusions of knowledge. Wealth and power are not prerequisites for illusions of knowledge, and neither are illusions of such knowledge the consequences of wealth and power. All humans suffer from this (mostly) non-fatal affliction. As with Henri Bonnet’s brain, the illusion of knowledge fills in for an absence of data and knowledge – erroneously.

But a civilization possessing “guns, germs, and steel” – to borrow from the title of the book by Jared Diamond of the same title – has the ability to act upon these illusions – often to the detriment of civilizations lacking equivalent means to resist the resulting economic and military domination. The results of these imbalances have been racism, slavery, colonialism, and imperialism, all wrapped in a protective cloak of cultural arrogance based on illusions of knowledge. These have led to a horrifying and ethically unsupportable blot on the conscience of the world for hundreds of years.

Even today, billions of people suffer from the consequences of this intolerable illusion of knowledge. What can be done to right these wrongs? As Nelson Mandela taught, you cannot hope for reconciliation until you have identified and acknowledged the truth. One of the goals of There Are No Foreign Lands is to acknowledge this truth.

Another goal is to inquire into the nature of intercultural communication, to make a good-faith effort to identify a path forward, unencumbered by illusions of knowledge.

Correcting such ethical errors begins with identifying the illusions of knowledge, purging them of their power to do harm, and reconstructing a world in which true knowledge is empowered to do good. There Are No Foreign Lands is a small, tentative contribution to the achievement of this monumental task.

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