Somehow my wife and I missed most of the original showing of the 6-part PBS series, "The Brain - With David Eagleman." We saw the final episode, and wanted to catch up on the rest.
So last night we streamed What is Reality?, the first episode. It's available on iTunes and Amazon Prime, with clips on the PBS web site. Here's one of the clips:
The basic neuroscientific message of this episode is that reality doesn't directly stream into consciousness through our senses, or by any other means. Instead, the brain does all sorts of processing of raw sensual data (photons, sound waves, scent molecules, etc.) before it reaches awareness.
So this supports a point I make frequently on this blog: there is no such thing as "reality as it is."
Sure, this phrase, and others like it, often is found in Buddhist and nondual writings, along with other spiritual, mystical, and meditation literature.
It doesn't have any foundation in fact, though. Eagleman shows quite a few experimental examples of how the brain selectively makes sense of the world by comparing incoming information with previous experiences.
This explains why we don't see a mysterious shape supported by round thingies. We see a car. The brain's processing of sense data occurs automatically, so usually it goes unnoticed. But Eagleman describes what happened when a man who became blind when he was three years old was able to see again late in life.
His eyes functioned perfectly, but he hasn't been able to see normally. One reason is that parts of his brain devoted to vision were converted to areas that process touch, sound, and other senses during his lengthy blindness.
Even for those of us with normal sensory inputs from birth, it doesn't matter how mindful or attentive we are to the world. We humans, along with every other sentient being, only are aware of a small fraction of reality.
And like I said, the portion we are conscious of gets heavily interpreted by the brain before we're aware of it. I recall Eagleman saying that more information flows from the cortex to a sensory area (thalamus, I believe) than the other way around.
Meaning, our awareness of reality is more dependent on previous experiences, than on what is being perceived by the senses here and now. The brain, Eagleman said, is continually updating its understanding of reality by processing mismatches between past and current experiences.
Another fascinating part of the What is Reality? episode was a description of what happened to a man imprisoned in Alcatraz who was put in a sensory deprivation "hole" part of the prison as a punishment. He was there for about three weeks, I recall.
No light. No sound. No contact with other people.
Soon he was seeing things. His brain, Eagleman explained, dealt with the lack of sense data coming in from outside by producing it from the inside.
And it wasn't just that he hallucinated sights and sounds. Rather, the man said, he began to experience a whole other reality. He was immersed in this new world, not just experiencing hallucinations in his jail cell.
Or, rather, he was, but the prisoner wasn't aware of this.
Just as a dream seems real while we're sleeping, the man entered another reality of his brain's own making during much of the time he was in the "hole." This reminded me of stories about mystics who spend months or years meditating in a dark room, cave, or wherever.
Given Eagleman's explanation of what the brain does when it is deprived of sensory input, it sure seems very possible, if not likely, that when these mystics describe other realms of reality that they supposedly entered, the "realms" actually were produced by processes within their own brains.
This hypothesis is supported by the fact that no one who claims to have experienced some sort of ethereal "heaven" has come back with verifiable knowledge of some previously unknown fact about our reality -- or any other evidence that what they experienced was objectively, rather than subjectively, real.
Anyway, I'm looking forward to seeing the other episodes of the PBS series that we missed. I've also ordered a copy of David Eagleman's companion book, "The Brain: The Story of You."