Back Goldfinch looking backwards

Much in this depends on what one under­stands by explaining a perception. Does correlating a neuronal spike with a patient’s reported perception constitute something by which to explain that perception? Perceiving Jennifer Aniston for me is more than some kind of spike in my consciousness.

Despite my constant request in emails for a definite argument or reference to one for the position that consciousness is entirely produced by brain function, my friend never provided me with one. She came close after four months of quite a few back and forth emails. See here for that.

How the Real World Thinks

A friend and colleague from my early days of college teaching, a retired professor, has kindly offered to criticize my little proof here, and in doing so provides me with a very solid example of How the Real World Thinks.

I came to my own understanding of mind apart from matter in large part through the realization that — despite the almost universal conviction to the contrary among the university educated of the world — there actually exists no scientifically verifiable study by any of the scientists with what the world calls the best current knowledge in the field of the biochemistry of the brain that shows or even tends to show that consciousness is entirely a product of brain function.

As for partially or to some extent, or in some manner, of course, that’s a different matter. It has been common knowledge since the work of Wilder Penfield in the 1950’s that physical stimulation of parts of the brain elicit changes in conscious states often of a very striking nature. And especially with the introduction of the fMRI in the 90’s people have come to know that certain parts of the brain “light up” when particular states of consciousness are engaged. Indeed, this procedure has been used to demonstrate what I call ghostly operations of minds in bodies. (For instance, here.)

I think it unlikely that anyone in the world’s dominant cultures maintains that a person’s consciousness is not most of the time somehow or another intertwined with her or his brain functioning. On the other hand, I know from personal experience with people and books that many well-read people also believe that when the brain ceases to function, so does consciousness. They believe that brain function is the sole source of mind. Furthermore, they believe that science has proven this to be the case — by repeatable (and repeated), verifiable experiments testing falsifiable hypotheses reported in peer-reviewed journals and all the rest.

Holding this belief makes it practically impossible to take seriously arguments of the sort I am making here. I understand this. I have been there, thought that. Dealing with a Holocaust denier or Watchtower wielder, reasoned argument appears futile. And so it is, from my point of view, just as it must be for the Jehovah's Witness, sad and frustrating to realize that my skeptical interlocutors are blinded in their reasoning with me by the fact that they think I’m an absolute nut.

In the absence, then, of any actual argument from my friend (>>>) that it is in fact a scientific fact that consciousness (or mind) is entirely dependent on matter, as in brain function, I have turned my attention to very recent writings on that topic by a notable young neuroscientist from MIT. I hope to find him directly making the argument for matter over mind, but my expectation is that he will not. I don’t know anyone who does.


Notes on Sebastian Seung, Connectome (How the Brain’s Wiring Makes Us Who We Are). The hardcover Houghton Mifflin edition of 2012. Seung has a nice appearance on Ted Talks in which he summarizes this book — link.

 Click this little icon () for page xviii and a little more comment. I think it makes clear his materialist position as well as his fundamental insight and strategy in neurophysiology.

After taking us through some of the highlights of brain science history as it sought to localize mind function in the brain, a trip clearly designed to show us how we need to go beyond merely localizing mind functions in more accurate phrenology maps, Seung closes chapter three on his main theme: “This is the deepest question of neuroscience: How could the neurons of your brain be organized to perceive, think, and carry out other mental feats? The answer lies in the connectome.”

I am now following the rest of his book carefully to see what kind of evidence he has for this claim. He does say right away that he doesn’t “know of any objective, scientific evidence for the soul.” I notice right away that this is exactly what I say of claims that mind is (exclusively) a product of brain activity. Now it appears that in what follows, Seung’s disposition of Leibniz’s well-known argument about mind and the windmill, he is offering us what he considers a pretty good demonstration that mind is entirely a product of brain activity:

In 1665 the German philosopher and mathematician Gottfried Wilhelm Leibniz argued for the latter {the one soul over many neurons}:

Furthermore, by means of the soul or form, there is a true unity which cor­responds to what is called the I  in us; such a thing could not occur in artificial machines, nor in the simple mass of matter, however organized it may be.

ln the last years of his life, he took the argument one step further, asserting that machines were fundamentally incapable of perception:

One is obliged to admit that perception and what depends upon it is inexplicable on mechanical principles, that is, by figures and motions. In imagining that there is a machine whose construction would enable it to think, to sense, and to have perception, one could conceive it enlarged while retaining the same proportions, so that one could enter into it, just like into a windmill. Supposing this, one should, when visiting within it, find only parts pushing one another, and never anything by which to explain a perception.

Leibniz could only imagine observing the parts of a machine that perceives and thinks - and he did so purely for the sake of arguing that no such machine could ever exist. But his fantasy has literally come true, if you regard the brain as a machine constructed from neuronal parts. Neuroscientists regularly measure the spiking of neurons in living, functioning brains. (The technology for measuring secretions is less advanced.) (61)

Now Seung takes us confidently through the results of a well-respected, well-known and recent set of experiments by Quiroga et al. (This link will likely be more helpful to the non-specialist reader.) The comments of other qualified scientists at the second link there, are useful for getting at the gist of the article (my emphasis):

I found this article interesting because it identifies a population of neurons in the human medial temporal lobe (particularly the hippocampus) which respond to specific famous people or monuments irrespective of the way they are represented: pictures, drawings or even written names.

These observations suggest that this family of neurons encodes a strikingly specific abstract representation of individuals or objects and that they may contribute to the formation of long term abstract memories.

René Hen Columbia University, USA Genomics & Genetics

In a fascinating report, Quiroga et al. present some of the most striking evidence to date for an explicit and invariant sparse coding mechanism for the mnemonic coding of the identity of people and objects, as opposed to a more broadly distributed mechanism.

They describe neurons in memory-related structures of the human brain (including the hippocampus, parahippocampal gyrus, amygdala and entorhinal cortex) that responded highly selectively and invariantly to different visual images of a specific famous person (e.g. a television or sports star), or a famous object (e.g. Tower of Pisa), or sometimes even to viewing the printed name of those people or objects.

John Kalaska University of Montreal, Canada Neuroscience

Seung concludes his use of this experiment this way:

So Leibniz was wrong. Observing the parts of the neuronal machine has told us a great deal about perception, even though neuroscientists have generally been limited to measuring spikes from a single neuron at a time. Some have measured spikes from tens of neurons simultaneously, but even this is meager compared with the enormous number of neurons in the brain. From the experiments that have been done so far, we might extrapolate: If I could observe the activities of all your neurons, I would be able to decode what you are perceiving or thinking. This kind of mind reading would require knowing the “neural code,” which you can picture as a huge dictionary. Each entry of the  dictionary lists a distinct perception and its corresponding pattern of neural activity. In principle, we could compile this dictionary by recording the activity patterns generated by a huge number of stimuli. (63)

What Kalaska (above) refers to as responding “highly selectively and invariantly to different visual images of a specific famous person” becomes in Seung’s engaging popularization the discovery of the Jennifer Aniston neuron. I have not given the core journal article by Quiroga et al. sufficient study to understand the highly complex and inferential process by which the experimenters reach the conclusion that corresponds to this popularization, but I certainly see that they are looking at something very much like that. They conclude on the neural code and dictionary idea —

The possibility of reading-out information from simultaneously recorded neurons in humans is of considerable value for assessing the feasibility and constrains of brain–machine interfaces, so-called neuroprosthetic devices.... Our study shows that such decoding is possible in patients, despite the nonoptimal clinical recording conditions, short experimental sessions, and lack of training.

So these scientists do appear to have found that in some people specific-person neurons can be identified. As Seung himself points out, despite the high specificity of response, the study has not eliminated the possibility that the, say, Eiffel Tower, neuron is not also a Roman Coliseum neuron, but they clearly are on to a promising insight the core of which is that there can be a highly reliable correlation between a person’s seeing a well-known image and the firing of electrical spikes across one specific neuron in their brain.

The experiment, of course, does not claim to eliminate the participation of other neurons in the recognition event, nor does it even claim that there may not exist dozens of other specific Jennifer Aniston neurons. There is naturally far more the experiment doesn’t do than what it does, but what it does do reinforces other evidence that perception and memory are closely tied to neuronal events, and, of course, it adds this nice specificity and the possibility of a primitive decoding of brain activity as well as interfacing with electrical machines outside the brain.

From my perspective, though, nothing has happened. The authors of the paper (Quiroga, Reddy, Koch and Fried) nowhere in their paper say anything about brain activity being the sole source of consciousness. Neither do any of the evaluators in the source above-given that includes Hen and Kalaska. I imagine that they share the near-universal assumption of scientists that brain activity is all there is, but they avoid commenting on that aspect of their thinking, and they see no reason to bring it in. Seung, on the other hand, is definitely in the arena with Leibniz and others who might believe in soul — something for which he has stated he has “no objective, scientific evidence.” The unstated implication of his presentation is that he thinks he has objective scientific evidence for the absence of soul in all these neuronal correlates with perception.

Certainly he has in mind objections to the thesis that all perceptions can be reduced to brain activity —

You might protest that perceptions are too complex to be reduced to something as simple as spiking. But remember that the spiking of a population of neurons defines a pattern of activity in which some neurons spike and others do not. The number of possible patterns is huge — more than enough to uniquely represent every celebrity, and indeed every possible perception. (63)

And I quoted him above concluding, just after this passage, in fact, “If I could observe the activities of all your neurons, I would be able to decode what you are perceiving or thinking.” For Seung, for sure, we are our neuronal activity or, better, we are our connectome. That is the thrust of his book — that something more is needed than sophisticated phrenology, which is what the Quiroga experiment is, if we are really to understand this wonderful thinking machine, the brain. But, of course, it is the machine, and only the machine, that does the thinking.

On the supposition, then, that Seung thinks this experiment of Quiroga and friends definitely establishes that brain activity is the sole source of consciousness and any parts of mind that may be supposed by some not to be present in consciousness, I will lay out some doubts I have as to the credibility of his position.

  1. Given that one spiking neuron (or any more complex pattern of firings and the like, brain processes) is the cause of the conscious experience of seeing the Eiffel Tower, why not come right out and say “sole” or “exclusive”?
  2. Why not entertain and explicitly reject any contrary hypotheses?
  3. Granting the spike as the sole cause of the conscious experience, in what sense is the cause the effect? Do the differences matter?

Elaborating the implications of the questions:

As for item 1, Seung and Quiroga and the others do not claim exclusive, unique or sole for their Eiffel Tower neuron for the obvious reasons that they have not excluded other neurons except for a few and they have no way of knowing whether the neuron might not have other functions in the life of the brain. Now in the same way that the experiment cannot rule out the involvement of other brain components in mediating the conscious experience of the photo of the Eiffel Tower, neither can it rule out non-physical or non-brain causal elements. It is strictly a matter of scientific faith to claim or think that this experiment and the many others like it establish that consciousness is not mediated by anything other than brain processes.

My question, Why not come right out and say “sole” or “exclusive”? supposes the thinking of my friend (linked above and here) that “it {the theory that mind is exclusively a product of brain activity} is being shown more and more likely with each advance in neuroscience.” I imagine that Seung and Quiroga and the rest agree with my friend in fact as to this experiment’s strengthening that idea about mind and brain. So why not just say so in so many words? (Seung clearly offers the Quiroga experiment for this strengthening purpose.) And the answer to that would be the underlined point in the paragraph above. Experiments like this have no bearing at all on the counter thesis (which has been around since, yes, ancient Greece) that brain is an intermediary between mind and consciousness. (See my pages on Other Minds’ Matter and Chris Carter.)

As for item 2, Seung very briefly glances at that possibility. He does not entertain it in the way of philosophy, does not actually examine it. He dismisses it cavalierly when he says he doesn’t “know of any objective, scientific evidence for the soul.” Of course, the objective, scientific evidence that there is, the argument that in fact needs to be entertained and explicitly and rationally refuted, does not refer to “soul” because that’s a loaded term generally reserved for theological discussions. It refers to “consciousness” just as he does, but argues that it does in fact exist apart from the brain. Perhaps Seung is in fact ignorant of the evidence, or perhaps he intends to disparage the whole idea in the minds of his very non-religious audience by using the word “soul.”

As for item 3, it raises an issue quite important in the philosophical discussions on the question of consciousness and brain process, one that would require a major digression to treat at all well, but I am nevertheless rather surprised that Seung does not at least glance at it. Perhaps that is because he knows some very heavyweight philosophers have raised the issue and cannot be dismissed with an airy “I know of no thoughtful objections to the idea that the cause of perception is essentially the same as perception.” Or maybe he’s just not read much outside his specialty.

Eventually I did find a Thomas Huxley argument from 1874. Click here for more.

Seung does not explicitly add “exclusively” to what the neuroscientists say, but it is clear from this context and everywhere else in the book that this is what he means, as it is, indeed, what they do mean by this understanding of homo sapiens sapiens. Sometimes this is made explicit, as in this statement:

Consciousness is entirely caused by brain processes. We don't know many of the details of these processes, although neurobiologists are making much progress in tracing them. But there isn't any real doubt that processes in our brains are causing our conscious experiences.

My emphasis there, in material from John R. Searle’s review of Nicholas Humphrey’s book, Seeing Red: A Study in Consciousness for the New York Review of Books, November 2, 2006.

Neither does Seung offer any actual evidence for what he claims. Measurements offer ample evidence, he says, without telling us what measurements or even in general how some sort of code might take us from measured neuronal activity to consciousness. Nor does he want to think the lovely convolutions of thought that must be required to persuade yourself that by means of your conscious experience and thinking you can prove quite conclusively that the inner life of your mind is actually the unseen but “rapidly changing patterns of neural activity in the brain.” It is in fact rather a tricky thing for me to think that thought and not think that I’ve just thought myself out of existence.

However, I do appreciate the elegance of Seung’s distinction of neuronal activity from the wiring, the stream bed of the the stream of consciousness, and I can see the logic of his wanting (as one sees later in the book and this preface, too) to have frozen brains to study after people’s death.

Interesting to speculate as to the form the decoding would take — a print out in words? Might pictures also be generated? And would that constitute having my perception? Would it be an explanation for my perception?

Since writing that, the necessity of addressing another argument by my friend (Real Scientists Don’t Use Statistics, I call it.) has driven me to pay detailed attention to the paper.  See this page.