Previously in this article, I explained how the brain's perceptual learning and memory storage system is organized. In today's post, I reveal the surprising source of my understanding. Here goes.
Liars and Thieves
In Part I, I wrote:
It turns out that the brain performs at least two essential functions while we are asleep: it purges liars (bad predictors) from sequence memory and eliminates thieves (redundant connections) from pattern memory.I am not going to go through a detailed explanation of how I arrived at my understanding because I would have to write a book. I probably will, eventually, but not today. I'm too busy. :-) Instead, let me just list one example to give you an idea of what I'm talking about. Here's where I got the idea for the liars and thieves metaphors:
Note: I will explain my choice of the liars and thieves metaphors in an upcoming post.
Then said he unto me, This is the curse that goeth forth over the face of the whole earth: for every one that stealeth shall be cut off as on this side according to it; and every one that sweareth shall be cut off as on that side according to it.After years of agonizing and thinking about it, I finally figured out, in the light of other passages, what the liars and thieves metaphors were all about. One day, some neurons in my cortex just made the right connections, and then, without warning, I understood what it all meant. Just like that.
I will bring it forth, saith the Lord of hosts, and it shall enter into the house of the thief, and into the house of him that sweareth falsely by my name: and it shall remain in the midst of his house, and shall consume it with the timber thereof and the stones thereof.
Source: Zechariah 5
A Little History on How It All Started
In December 1999, I made an amazing discovery, one that would transform my life. As a Christian, I had long suspected that some of the metaphorical passages in several Old and New Testament books were scientific in nature. I knew that, one day, their true meaning would be deciphered to reveal world-changing scientific knowledge. To me, it was inconceivable that Yahweh would go to great lengths to hide certain information for future advanced generations just for grins and giggles. I also felt that the various interpretations of the metaphors that I had seen in the Christian literature were not only stale and nonsensical but they did something even more reprehensible: they insulted Yahweh's intelligence with their banality.
At the time, I was researching artificial intelligence and, after many years of study, I had developed the beginning of a theory of intelligence. Things were starting to make sense a little and then I came face to face with the brick wall of my own ignorance. Progress just stopped. One evening, while reading the book of Revelation, it suddenly occurred to me that chapters 2 and 3 (known commonly as the letters to the seven churches of Asia) were a detailed metaphorical description of the organization and working of the left hemisphere of the brain. Color me crazy (I don't care) but I could see a clear correspondence between a couple of the metaphors and objects in my own AI model. I trembled with excitement.
Where others saw strangely worded admonitions to a handful of first-century Christian churches, I saw sensors, effectors, signals, hierarchies, patterns and sequences, perceptual learning, motor learning, success and failure, fitness criteria, etc. I knew nobody would believe it but, to me, the general meaning of the text was unmistakable. It just needed to fleshed out, that's all. Then my investigation of the message to the Church of Sardis soon led me to discover the book of Zechariah (The Lord Remembers), an amazing fountain of knowledge about memory organization, attention and pattern recognition. I was overwhelmed.
I remember the time I finally figured out that the two olive trees on both sides of the golden lampstand did not represent the trees of knowledge in the left and right hemispheres of the brain, as I had originally assumed. I had no real reason to make that assumption other than the observation that the brain consisted of two hemispheres. The analogy seemed to fit at the time but it was wrong. It took me years to realize I was hopelessly lost. I was forced to retrace my steps to that fork in the road and take the other path, the one that I had previously dismissed. It was like finding an opening out of the forest.
I could see clearly for the first time. I understood that the brain's memory consisted of two hierarchies, one for concurrent patterns (fig trees) and one for sequences (vine).
In that day, saith the Lord of hosts, shall ye call every man his neighbour under the vine and under the fig tree. Zechariah 3:10I understood the importance and meaning of the Branch metaphor in Zechariah's text with respect to knowledge construction, attention and invariant recognition. I understood the metaphors of the flying scroll, the thieves and the liars. I understood why sequence memory was a hierarchy of seven-node chunks or building blocks. I understood what the brain was up to during sleep and why. I understood that the mainstream Bayesian approach to AI was deeply and fundamentally flawed, in spite of its successes. I knew why the brain went to great lengths to eliminate uncertainty.
I understood a lot of things. It felt sort of like what Mr. Anderson might have felt in the Matrix movie, when he wakes up from a virtual reality session and announced that he knew Kung-Fu.
Not long after that fateful evening in December 1999, my elation quickly faded when I realized that it was not going to be that easy to extract the full meaning of those ancient metaphors. I noticed that almost every word used in the metaphorical texts was pregnant with powerful and subtle meanings that were easily overlooked. I was forced to commit myself to carefully analyse everything in detail. I made slow progress over the years but I kept at it. Progress came in fits and starts but I think I have come a long way. I don't yet understand it all but it's just a matter of time before I do. Almost everything I wrote in this article regarding the brain came from my interpretation of the ancient metaphors.
Let me conclude by saying that I am not asking anybody to believe me. Whether you take it or leave it, is up to you. But do keep your ears and eyes open. It will get a lot more interesting in the not too distant future.
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