How many minds can one organism have? (Answer: One.)

I was asked this question on Quora:

Do the two halves of the brain have wills of their own? Can they dislike each other or fight?

Here’s my answer:

It’s very difficult to define what exactly the will is in neuroscientific terms. It seems best to reserve this word for the whole organism, rather than some part of it.

Some philosophers would say that attributing will to some sub-component of an organism is an example of the “mereological fallacy”. It’s like saying the stomach eats, or the brain thinks, or the legs walk. We use these kinds of phrases as a kind of poetic shorthand, but only a complete organism can be said to eat, think, or walk.

In the case of the two hemispheres, we also know that the left brain right brain story — that one is “rational” and the other “holistic/artistic” — is wildly misguided. Some neural processes are lateralized, but most normal tasks that humans perform require close integration and communication between the hemispheres.

But we do have to make sense of a common experience — being “in two minds” about something. Most people know what it is like to be in a conflicted state — multiple goals or biases seem to be tugging at us. Clearly decision-making involves a sort of “parliamant” in the brain, in which multiple vested interests vie to enact legislation that suits them. 🙂

But the parliament metaphor should not be taken too seriously. There is little to be gained in anthropomorphizing neurons or groups of neurons. Neural ensembles might sometimes seem to behave as if they have a will, but that idea will not really help us understand decision-making, or the subjective feeling of having a will.

So brain areas don’t have likes or dislikes — organisms do, and brain areas mediate the processes by which these likes and disliked become manifest.

For more on the problems with anthropomorphizing neural processes, see these two essays I wrote:

Persons all the way down: On viewing the scientific conception of the self from the inside out | 3 Quarks Daily (This essay is partly a gentle critique of the Pixar movie Inside Out.)

Me and My Brain: What the “Double-Subject Fallacy” reveals about contemporary conceptions of the Self | 3 Quarks Daily (This essay explores the tendency of people, including neuroscientists, to think of the brain is a separate agent from the person as a whole.)

I admit that it is often fun to anthropomorphize neurons, which is what I do in the essay below. I paint a picture of a neural city and a neural economy, complete with start-ups and investors. 🙂

Be Careful What You Wish For: Some Wild Speculation on Goodhart’s Law and its Manifestations in the Brain | 3 Quarks Daily


Further reading

Yohan John’s answer to Is the left brain and right brain concept a myth, or is it true?

Yohan John’s answer to What happens to consciousness when the brain’s two cerebral hemispheres are disconnected?

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A Clockwork Orange? (A brief musing on the concept of a neural “code”)

I was asked this question on Quora:

Are there many layers of neural codes from the human retina to the optic nerve and the optic nerve to the brain, or are they essentially same signals relayed?

Here’s how I responded:

Here’s a question: in a system composed of clockwork, is there a “code”?

I ask this because I find that the “code” metaphor is often misleading when thinking about biology. Codes are composed of symbols. But it is not clear that neurons communicate using symbols.

The way a neuron affects other neurons is more like how a gear affects other gears. There is no code — there is causality. An active neuron releases some neurotransmitter, and this in turn makes other neurons more active. It’s like a complex network of dominoes.

Does the idea of a “code” help us understand how one domino affects the next one in the chain?

I admit that by the time a human is thinking in terms of words and symbols, “code” is probably a useful metaphor for what is going on. But the origin of coding schemes remains a great mystery in neuroscience, cognitive science, and artificial intelligence. So I recommend starting with a much less loaded metaphor, such as clockwork or dominoes. Thinking in mechanical terms helps us realize what exactly neuroscience and AI research are trying to achieve.

For now, there is a fascinating gap in our understanding of what exactly codes are in the first place.


Anyway, if you are interested in the causal “domino effect” that starts at the retina, have a look at this answer:

Yohan John’s answer to In which format is information stored in the brain?

 

“Are thoughts just a bunch of electrical and chemical signals being tossed around inside the brain, or is there more to it than that?”

“In our world,” said Eustace, “a star is a huge ball of flaming gas.”

“Even in your world, my son, that is not what a star is but only what it is made of…”

The Voyage of the Dawn Treader, CS Lewis

I really like the quote above, which is from the Chronicles of Narnia. It raises a neat little metaphysical question:

Why do we assume that what a thing is made up of is what a thing is?

As a neuroscientist I have to point out that no one really knows what a thought is from a scientific perspective. This means that we don’t know what we would need to measure in order to ‘decode’ a person’s thoughts. For the foreseeable future, I cannot look at a brain scan and say, “This person is definitely thinking about pineapples!”

Of course, thoughts seem to be closely linked with neural patterns in the brain, and those patterns are clearly linked with electro-chemical signaling. Tinkering with the signaling clearly tinkers with the thinking. Otherwise the effects of drugs such as alcohol and coffee on thought would be a mystery. Perhaps some day we will have a scanner that tells us what a person is thinking of.


Matter and form

While I admit that electro-chemical signals being tossed about is a necessary precondition for thinking — no phenomenon that lacks such tossing will be unanimously labeled as thinking — I think that material constituency is a less than stellar guide for thinking about what something is.

Consider charcoal, diamonds, graphite, and graphene. These are made up of carbon. But is that all there is to the story of what they are? I hope the answer is an emphatic no, since they all have radically different properties. Charcoal is black and relatively soft. Diamonds are transparent and exceptionally hard. Graphene and graphite conduct electricity whereas other forms do not.

What explains the differences between the various allotropes of carbon? Clearly it isn’t what they are made of — it’s the same stuff in each case.

Eight allotropes of carbon: a) diamond, b) graphite, c) lonsdaleite, d) C60 buckminsterfullerene, e) C540, Fullerite f) C70, g) amorphous carbon, and h) single-walled carbon nanotube. Source: Wikipedia

~

What differs among the allotropes is the arrangements of carbon atoms. In other words, form is as important as ‘content’. Depending on how you arrange carbon atoms, you will end up with something soft and opaque or hard and transparent. Clearly the properties of the substances are not to be found in the properties of the atoms.

This is generally true for most complex and interesting objects and processes. You can boil them down to some set of elements — and these elements maybe subatomic particles, atoms, molecules, genes, cells, neurotransmitters — but some defining feature of the overarching process will be missing from the constituent parts considered in isolation, just as transparency or opaqueness are missing from individual carbon atoms.

In complex systems theory and in condensed matter physics, the word emergence is often used to describe the phenomenon by which collections of matter acquire new properties as a result of arrangement or sheer scale. Chemistry is full of examples. Oxygen is a gas. Hydrogen is a gas. But when they combine together in the right way, they produce water, which is a liquid — and one with all kinds of properties that can’t be predicted from first principles through analyzing the constituent parts.


Are thoughts emergent?

Since we don’t know exactly what thoughts are, we cannot say for sure whether they are emergent phenomena or not. But we can indirectly infer that they are by considering properties of thoughts and comparing them with properties of chemicals being tossed around in the brain.

A hallmark of thoughts is that they are about things. When you are thinking about a pineapple, there is an “aboutness” relation between the thought and the pineapple. Thoughts refer to things — which may be real things in the world, or imaginary things like dragons. This is a distinctive feature of mental phenomena, and the philosophers call it intentionality. (Note that intentionality has nothing to do with intentions or motivations — it’s not the best term, but that’s where you’ll find the relevant writings.)

This “aboutness” or “intentionality” is not a feature of chemical tossing patterns. A pattern is a pattern is a pattern, and isn’t intrinsically about any other pattern. At the very least, we can say that modern physics and chemistry have had no reason to invent an “aboutness” concept so far. In other words, there is no purely physical theory of reference.

So it seems reasonable to at least consider the possibility that the property of “aboutness” emerges when matter is arranged in just the right way.


“Is there more to it?”

This admittedly abstract concept is not really going to satisfy people who were hoping that thoughts were actually composed of “magic dust”, as Sam Moss quite rightly termed it. Thoughts are not “made up” of some special secret sauce. If you look at a brain — or any other tissue — under a microscope, all you see are cells. And cells are made up of atoms — mostly carbon, hydrogen and oxygen, with some crucial cameos by nitrogen, calcium, phosphorus, sulfur, sodium, potassium, magnesium and choride.

So is that all a brain or a body is? A stew of a dozen elements? If you followed the story with carbon, then you’ll know that the answer is no. The arrangement of the atoms makes all the difference in the world.

But does this mean that “there is more to it”? If “more” implies a substance of which thoughts are made, then the answer is most likely no.

In any case, given that matter makes up everything, saying that something is “just” matter seems a bit unfair to matter — it’s about as magical a dust as you could possibly hope for!

Matter gives you the universe and you ask if there is more to it?! 😉

If you like, you can call arrangement or form the special “something more”. Arrangement is the “something more” that distinguishes charcoal from diamonds, and thought from nonsense.

But arrangement will not fulfill all the duties of magical dust. It is not the same as the traditional notion of a soul. A soul can live on without a body. But a form has no meaning without the constituent matter that is arranged.

So here’s the compromise: thoughts are made up of electro-chemical signals tossing around, but that is not what they are, since this definition does not distinguish in any useful way between thoughts and perceptions, feelings, moods, emotions or sensations — or even unconscious neural processes for that matter — all of which are also made up of electro-chemical signals.

So saying thoughts are electro-chemical signals is about as useful as saying diamonds are carbon. It’s true, but not in an especially interesting or informative sense.


Notes

If you’ve made it this far, well done! I guess I was having a slow Friday evening! 🙂

I know that what I’ve written is quite abstract, but that goes with the territory if you are thinking about thoughts.

Here are some answers that may be of interest:

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This post was originally a Quora answer.

Is a memory a bunch of atoms? And does this mean we can transfer exact memories?

I was asked the following question on Quora.

Are specific memories just arrangements of atoms in our brains? Could you put certain molecules in someones head and give them an exact memory that you had?

Short answer: No.


Modern science has shown that every thing is an arrangement of atoms: neurons, apples, tables, rockets, asteroids, aardvarks… they are all made up of atoms.

The question now is this: is a memory a thing?

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Are mental disorders the same as brain disorders? Maybe not!

I am currently reading an excellent paper that will be published in Behavioral and Brain Sciences soon. It raises some very important issues with popular conceptions of mental illness.

Brain disorders? Not really… Why network structures block reductionism in psychopathology research

These two figures capture some of the key points:

Here is the abstract:

“In the past decades, reductionism has dominated both research directions and funding policies in clinical psychology and psychiatry. However, the intense search for the biological basis of mental disorders has not resulted in conclusive reductionist explanations of psychopathology. Recently, network models have been proposed as an alternative framework for the analysis of mental disorders, in which mental disorders arise from the causal interplay between symptoms. In this paper, we show that this conceptualization can help understand why reductionist approaches in psychiatry and clinical psychology are on the wrong track. First, symptom networks preclude the identification of a common cause of symptomatology with a neurobiological condition, because in symptom networks there is no such common cause. Second, symptom network relations depend on the content of mental states and as such feature intentionality. Third, the strength of network relations is highly likely to partially depend on cultural and historical contexts as well as external mechanisms in the environment. Taken together, these properties suggest that, if mental disorders are indeed networks of causally related symptoms, reductionist accounts cannot achieve the level of success associated with reductionist disease models in modern medicine. As an alternative strategy, we propose to interpret network structures in terms of D. C. Dennett’s (1987) notion of real patterns, and suggest that, instead of being reducible to a biological basis, mental disorders feature biological and psychological factors that are deeply intertwined in feedback loops. This suggests that neither psychological nor biological levels can claim causal or explanatory priority, and that a holistic research strategy is necessary for progress in the study of mental disorders.”

Behavioral and Brain Sciences is one of the premier journals for “big thinking” in cognitive science and neuroscience, so it’s great to see these ideas there.

Why can’t we perceive cells? Or atoms?

I was asked the following question on Quora:

Why can’t we see, touch, hear and smell on a cellular level? And what happens if we can?

Here’s what I wrote:

Essentially, we perceive the visible world in the way that we do because of our overall size, the shape of our eyes, and the sizes of objects in the world that are relevant to our voluntary behavior.

This question might seem silly, but a closely related question can serve as a springboard for us to think very deeply about physical scale, and how it relates to biological life and to the very concept of a scientific law.


But first lets deal with the basic question.

Continue reading

Is the mind a machine?

My latest 3QD essay explores the “mind as machine” metaphor, and metaphors in general.

Putting the “cog” in “cognitive”: on the “mind as machine” metaphor

Here’s an excerpt:

People who study the mind and brain often confront the limits of metaphor. In the essay ‘Brain Metaphor and Brain Theory‘, the vision scientist John Daugman draws our attention to the fact that thinkers throughout history have used the latest material technology as a model for the mind and body. In the Katha Upanishad (which Daugman doesn’t mention), the body is a chariot and the mind is the reins. For the pre-Socratic Greeks, hydraulic metaphors for the psyche were popular: imbalances in the four humors produced particular moods and dispositions. By the 18th and 19th centuries, mechanical metaphors predominated in western thinking: the mind worked like clockwork. The machine metaphor has remained with us in some form or the other since the industrial revolution: for many contemporary scientists and philosophers, the only debate seems to be about what sort of machine the mind really is. Is it an electrical circuit? A cybernetic feedback device? A computing machine that manipulates abstract symbols? Some thinkers so convinced that the mind is a computer that they invite us to abandon the notion that the idea is a metaphor. Daugman quotes the cogntive scientist Zenon Pylyshyn, who claimed that “there is no reason why computation ought to be treated merely as a metaphor for cognition, as opposed to the literal nature of cognition”.

Daugman reacts to this Whiggish attitude with a confession of incredulity that many of us can relate to: “who among us finds any recognizable strand of their personhood or of their experience of others and of the world and its passions, to be significantly illuminated by, or distilled in, the metaphor of computation?.” He concludes his essay with the suggestion that “[w]e should remember than the enthusiastically embraced metaphors of each “new era” can become, like their predecessors, as much the prisonhouse of thought as they at first appeared to represent its liberation.”

Read the rest at 3 Quarks Daily:

Putting the “cog” in “cognitive”: on the “mind as machine” metaphor