Just Call Them "Machine-Metaphor-Misguided"

A recent interview on the website www.vox.com inadvertently gives us a portrait of the scrambled thinking of modern neuroscientists, whose thinking about the brain is senselessly guided not by the low-level characteristics of the brain discovered by neuroscientists, but by silly mechanical metaphors in which the non-mechanical brain is constantly compared to machines invented by men.  The article containing the interview begins with the statement, "It’s difficult to talk about the human brain without inadvertently talking about computers."  No, that isn't true. 

The interview is with a zoologist named Matthew Cobb, who has written about the history of ideas about the brain.  Cobb had some insightful and intelligent-sounding things to say about the improbability of eukaryotic cells evolving, which I quoted in a 2017 post.  But in this interview his answers are empty-sounding. 

Cobb makes it sound like scientists have a history of comparing the brain to whatever is the most impressive communications technology available in a particular time. So when the telegraph was the latest and greatest in communication technology (around 1850), the brain was compared to a telegraph; and when telephone technology was the latest and greatest in communication technology (in the early twentieth century), the brain was compared to a telephone switchboard; and when computers and Internet-capable devices were the latest and greatest in communications technology, the brain was compared to a computer. 

None of these metaphors ever made sense. Telegraph systems, telephone systems and computer systems all are based on the signal transmission in copper wires that transmit signals with near-100% reliability.  The chemical synapses in the brain that are by far the most common type of synapses have no such reliability. Tests have shown that in a chemical synapse the probability of successful transmission is less than 50%. 

In an interview, an expert on neuron noise states the following:

"There is, for example, unreliable synaptic transmission. This is something that an engineer would not normally build into a system. When one neuron is active, and a signal runs down the axon, that signal is not guaranteed to actually reach the next neuron. It makes it across the synapse with a probability like one half, or even less. This introduces a lot of noise into the system."

So according to this expert, synapses (the supposed storage place of human memories) transmit signals with a probability of less than 50 percent. That's very heavy noise – the kind of noise you would have if half of the characters in your text messages got scrambled by your cell phone carrier.  A scientific paper tells us the same thing. It states, "Several recent studies have documented the unreliability of central nervous system synapses: typically, a postsynaptic response is produced less than half of the time when a presynaptic nerve impulse arrives at a synapse." Another scientific paper says, "In the cortex, individual synapses seem to be extremely unreliable: the probability of transmitter release in response to a single action potential can be as low as 0.1 or lower."

Another reason it never made sense to compare the brain to a telegraph system is that telegraph systems are based on a particular signal transmission code (the Morse Code) invented by Samuel Morse; but no one has ever discovered any evidence of any code system in the brain by which complex learned information can be reliably transmitted or stored or retrieved.  No one has ever discovered a "brain code" or a "neuron code" analagous to the Morse Code.  

It also never made any sense to compare the brain to a telephone switchboard. In an old-fashioned telephone switchboard, a caller would be routed exclusively to one particular telephone number.  For example, a switchboard operator (after getting a request) might cause the caller with the number 342-2352 to be exclusively routed so that one and one phone number would ring: the number 342-4252.   But the brain does not work like that. Most neurons are connected to very many other neurons.  A scientific paper tells us, "Each neuron may be connected to up to 10,000 other neurons, passing signals to each other via as many as 1,000 trillion synapses."

This is actually an extremely strong reason for rejecting all claims that memory recall occurs in brains or that memories are stored in brains or that brains produce thinking.  In my long post here I discuss this point at great length.  I'll give just a short summary of my reasoning: reliable signal transmission only occurs when there is an exclusive or near-exclusive relation between a receiver and a transmission source. That's why TV sets never receive ten channels at the same time. When a receiver is bombarded by signals from very many sources at the same time, it would be like a TV that is simultaneously getting broadcasts from very many TV channels. The result would be an unintelligible jumble kind of like the mess shown in the visual below:

A jumble rather like the one above is something we should expect from a brain in which each neuron is always getting signals from very many other neurons, except that the jumble and unintelligibilty would be far worse; for most neurons receive signals from very many other neurons. 

But what about the modern-day "brain as computer" metaphor? It never made any sense. To understand why, just read my post entitled "The Brain Has Nothing Like 7 Things a Computer Uses to Store and Retrieve Information." Below are the things I mentioned, things that are crucial components of computers, but have no counterpart in the brain:

• An Operating System
• An Application to Store and Retrieve Data
• The ASCII Code for Encoding Information
• A Decimal to Binary Conversion Table or Utility
• A Medium That Allows a Permanent, Stable Storage of Information
• A Storage Location System by Which the Exact Position of a Data Item Can be Specified, Allowing Fast Retrieval from an Exact Location
• Read/Write Functionality Allowing Data to Be Written to a Specific Location and Also Read From the Same Location

Asked about when scientists first started assuming that thinking comes from the brain, we get a very revealing answer from Cobb, an answer that inadvertently reveals the lack of any sound foundation for such an idea.  The answer is a minor classic of empty  insubstantiality. Here is Cobb's answer about when scientists first started assuming that thinking comes from the brain:

"Not in one moment. You mustn’t get the idea that somebody suddenly did an experiment and said, 'Aha!' Instead, there’s this slow accumulation of certainty. First, there’s anatomical demonstration that the 'viscera' like the heart have other functions. The heart is a pump, which was demonstrated at the beginning of the 17th century — so it doesn’t have the wherewithal to do the mysterious business associated with perception and thinking and so on. On the other hand, the brain, as anatomical studies showed, has got all these neurons, and it’s connected by the neurons to all the sense organs and everything else. So gradually, in the course of the 17th century in particular, people became increasingly confident that it was the brain that was doing thinking. How it did it, they weren’t quite sure."

Cobb confesses that there was never any experiment that caused scientists to assume that brains think.  He suggests that showing that hearts probably don't think was some reason for thinking that brains think, which makes no sense at all. You do not show that one organ does something by showing that some other organ does not do that thing.  The fact that neurons are connected to sense organs does nothing to show that brains cause thinking.  The phrase "slow accumulation of certainty" is very misleading. There has never been any certainty that brains think, nor any sound basis for believing that they do think.  

To the contrary, there are the strongest reasons for thinking that brains cannot possibly be the cause of lightning-fast human thinking. They include the following:

• The fact that no one has the slightest idea of how any arrangement of neurons could ever cause the arising of abstract ideas. Cobb's claim that neuroscientists aren't quite sure of how a brain could think is misleading. The truth is they haven't the slightest credible idea of how such a thing could occur.  
• The fact that severe slowing factors should make it impossible for brains to produce the lightning fast thinking that occurs in people such as math savants who can produce very complex calculations with astonishing speed. 
• The fact that unreliable synaptic transmission (discussed above) should make accurate memory recall and very accurate thinking impossible, contrary to the reality that humans such as Hamlet actors can recall large bodies of text with perfect accuracy, and other humans can do very complex mental calculations "in their head" with perfect accuracy.

An extremely important point about human thinking is that some people are capable of doing very complex thinking with blazing speed and perfect accuracy.  The natural limitations of the brain (very heavy signal noise, many internal slowing factors, and unreliable synapse transmission) rule out the brain as a source of such phenomena. An example of such a person is Neelakantha Bhanu Prakash, called "the world's fastest calculator." He can do things such as accurately multiply 869,463,853 times 73 in just 20 seconds. This is despite the fact that he had a very bad brain injury in a motorcycle crash, an injury to the front of his head so bad it required 85 stitches, multiple operations and a medically induced coma to treat.  He still has a prominent scar on his forehead as a reminder of the accident. 

Later in the interview discussed above, Cobb makes this very misleading statement comparing brain wiring to undersea transatlantic cables:

"They looked, for example, at the structure of undersea cables that were carrying telegraph messages across the Atlantic, and they could see that there was a central core of copper and then around it was insulation. And then they looked at neurons, at nerves, and they said, 'Well, this is exactly the same.' " 

Many readers probably read that statement and thought: "Gee, I didn't know there are copper wires inside the brain." There are no such things. There are what are called myelinated axons in the brain that transmit signals quickly. But in the grey matter cortex of the brain the great majority of axons are not well myelinated. A scientific text co-written by a Yale scientist says this:

"The axons of grey matter are not heavily myelinated, unlike white matter, which contains a high concentration of myelin. The grey matter contains the majority of neuron somas, making it appear tan with circulation but grey when prepared for examination outside of the body. These somas are circular structures that house the nucleus of the cells."

Besides the lack of myelination in the grey matter of the brain, there's a crucial reason why the "transatlantic cable" analogy is profoundly misleading. The 1866 transatlantic cable was capable of transmitting eight words per minute across the Atlantic ocean, because of a lack of any "speed bumps" that would slow down the signal. In the cortex there are "speed bumps" all over the place.  They include the following:

(1) The speed of transmission through dendrites, which can be 200 or more times slower than the "100 meters per second" estimate based on transmission through well-myelinated axons. According to one expert, dendrites make up 90% of neural tissue. 
(2) Synaptic delays, each about .5 millisecond, which end up being a huge slowing factor because so very many synapses must be traversed to pass through a decent amount of cortex tissue.
(3) Synaptic unreliability or noise, the fact that a signal across a synapse is typically transmitted with only between 10% to 50% likelihood, a factor that is typically ignored but which has a huge impact on effective speed.
(4) Synaptic fatigue, the fact that a synapse will so often need a rest period after firing, a period that can be more than a minute.
(5) Tortuosity, the fact that nerve signals must travel through sinuous paths that are not straight lines.
(6) Folding of cortex tissue, a further slowing factor. 

(7) Low myelination in the cortex, where the gray matter has little myelination. 

Every one of these factors is ignored by 95% of discussions of brain signal speed in the popular press. Altogether these factors should cause us to conclude that the brain cannot possibly be the source of very fast recall and very fast thinking in people such as mathematical savants. 

After discussing how brains were first compared to telegraph systems and then compared to telephone systems, Cobb is asked "what came after the telephone?" He describes the latest silly machine metaphor, whose silliness he fails to perceive:

"Well, the dominant metaphor is that the brain is something like a computer. It’s carrying out some kind of calculations. And that idea, which came into being in the 1940s and early 1950s, still dominates over 70 years on." 

To see why this metaphor makes no sense, read my post entitled "The Brain Has Nothing Like 7 Things a Computer Uses to Store and Retrieve Information."  Among the reasons why it is senseless to claim that brains make minds and brains are like computers, some additional reasons are:

• Minds are conscious, and computers are not.
• Minds can have novel abstract ideas, and computers cannot. 
• Minds can have curiosity and morality, but computers cannot. 
• Minds have experience and feelings, and computers do not. 
• Minds can be interested in things, but computers cannot. 
• Minds can experience pleasure and pain, but computers cannot.

A very general question that we should be asking again and again to scientists is: "What forced you to believe that?" When there is a good evidence basis for thinking something, scientists will be able to discuss some evidence that forced them to believe some particular thing, regardless of whether they wanted to.  There is nothing at all that forced scientists to believe that brains produce thinking. They simply adopted such a belief because they didn't want to believe in souls or because they wanted to say they had an answer to a deep question they did not understand.  The lack of any good evidence  basis for believing that brains produce thinking is suggested by the very wobbly "not in one moment" answer given by Cobb quoted above. 

Neuroscientists should not be asking, "What machine created by humans should we compare the brain to?" Instead, neuroscientists should be asking, "What low-level facts that we have learned about the brain should cause us to reduce and limit our ideas about what the brain could be capable of?" Above I have listed many such facts, senselessly ignored by neuroscientists.  There are many other such facts mentioned in other posts on this blog.