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Monday, July 4, 2011

On discovering you’re an android

Deckard: She's a replicant, isn't she?
Tyrell: I'm impressed. How many questions does it usually take to spot them?
Deckard: I don't get it, Tyrell.
Tyrell: How many questions?
Deckard: Twenty, thirty, cross-referenced.
Tyrell: It took more than a hundred for Rachael, didn't it?
Deckard: [realizing Rachael believes she's human] She doesn't know.
Tyrell: She's beginning to suspect, I think.
Deckard: Suspect? How can it not know what it is?

A very discomfiting realisation, discovering you are an android. That all those thoughts and ideas and feelings you seem to be having are just electrical impulses zapping through your circuits. That you are merely a collection of physical parts, whirring away. What if some of them break and you begin to malfunction? What if they wear down with use and someday simply fail? The replicants in BladeRunner rail against their planned obsolescence, believing in the existence of their own selves, even with the knowledge that those selves are merely the products of machinery.

The idea that the self, or the conscious mind, emerges from the workings of the physical structures of the brain – with no need to invoke any supernatural spirit, essence or soul – is so fundamental to modern neuroscience that it almost goes unmentioned. It is the tacitly assumed starting point for discussions between neuroscientists, justified by the fact that all the data in neuroscience are consistent with it being true. Yet it is not an idea that the vast majority of the population is at all comfortable with or remotely convinced by. Its implications are profound and deeply unsettling, prompting us to question every aspect of our most deeply held beliefs and intuitions.

This idea has crept along with little fanfare – it did not emerge all at once like the theory of evolution by natural selection. There was no sudden revolution, no body of evidence proffered in a single moment that overturned the prevailing dogma. While the Creator was toppled with a single, momentous push, the Soul has been slowly chipped away at over a hundred years or more, with most people blissfully unaware of the ongoing assault. But its demolition has been no less complete.

If you are among those who is skeptical of this claim or who feels, as many do, that there must be something more than just the workings of the brain to explain the complexities of the human mind and the qualities of subjective experience (especially your own), then first ask yourself: what kind of evidence would it take to convince you that the function of the brain is sufficient to explain the emergence of the mind?

Imagine you came across a robot that performed all the functions a human can perform – that reported a subjective experience apparently as rich as yours. If you were able to observe that the activity of certain circuits was associated with the robot’s report of subjective experience, if you could drive that experience by activating particular circuits, if you could alter it by modifying the structure or function of different circuits, would there be any doubt that the experience arose from the activity of the circuits? Would there be anything left to explain?

The counter-argument to this thought experiment is that it would never be possible to create a robot that has human-like subjective experience (because robots don’t have souls). Well, all those kinds of experiments have, of course, been done on human beings, tens of thousands of times. Functional magnetic resonance imaging methods let us correlate the activity of particular brain circuits with particular behaviours, perceptions or reports of inward states. Direct activation of different brain areas with electrodes is sufficient to drive diverse subjective states. Lesion studies and pharmacological manipulations have allowed us to map which brain areas and circuits, neurotransmitters and neuromodulators are required for which functions, dissociating different aspects of the mind. Finally, differences in the structure or function of brain circuits account for differences in the spectrum of traits that make each of us who we are as individuals: personality, intelligence, cognitive style, perception, sexual orientation, handedness, empathy, sanity – effectively everything people view as defining characteristics of a person. (Even firm believers in a soul would be reluctant recipients of a brain transplant, knowing full well that their “self” would not survive the procedure).

The findings from all these kinds of approaches lead to the same broad conclusion: the mind arises from the activity of the brain – and nothing else. What neuroscience has done is correlated the activity of certain circuits with certain mental states, shown that this activity is required for these states to arise, shown that differences in these circuits affect the quality of these states and finally demonstrated that driving these circuits from the outside is sufficient to induce these states. That seems like a fairly complete scientific explanation of the phenomenon of mental states. If we had those data for our thought-experiment robot, we would be pretty satisfied that we understood how it worked (and could make useful predictions about how it would behave and what mental states it would report, given enough information of the activity of its circuits).

However, many philosophers (and probably a majority of people) would argue that there is something left to explain. After all, I don’t feel like an android – one made of biological rather than electronic materials, but a machine made solely of physical parts nonetheless. I feel like a person, with a rich mental life. How can the qualities of my subjective experience be produced by the activity of various brain circuits?

Many would claim, in fact, that subjective experience is essentially “ineffable” – it cannot be described in physical terms and cannot thus be said to be physical. It must therefore be non-physical, immaterial or even supernatural. However, the fact that we cannot conceive of how a mental state could arise from a brain state is a statement about our current knowledge and our powers of imagination and comprehension, not about the nature of the brain-mind relationship. As an argument, what we currently can or cannot conceive of has no bearing on the question. The strong intuition that the mind is more than just the activity of the brain is reinforced by an unfortunate linguistic accident – that the word “mind” is grammatically a noun, when really it should be a verb. At least, it does not describe an object or a substance, but a process or a state. It is not made of stuff but of the dynamic relations between bits of stuff.

When people argue that activity of some brain circuit is not identical to a subjective experience or sufficient to explain it, they are missing a crucial point – it is that activity in the context of the activity of the entire rest of the nervous system that generates the quality of the subjective experience at any moment. And those who dismiss this whole approach as scientific reductionism ad absurdum, claiming that the richness of human experience could not be explained merely by the activity of the brain should consider that there is nothing “mere” about it – with hundreds of billions of neurons making trillions of connections, the complexity of the human brain is almost incomprehensible to the human mind. (“If the brain were so simple that we could understand it, then we would be so simple that we couldn’t”).

To be more properly scientific, we should ask: “what evidence would refute the hypothesis that the mind arises solely from the activity of the brain”? Perhaps there is positive evidence available that is inconsistent with this view (as opposed to arguments based merely on our current inability to explain everything about the mind-brain relationship). It is not that easy to imagine what form such positive evidence would take, however – it would require showing that some form of subjective experience either does not require the brain or requires more than just the brain.

With respect to whether subjective experience requires the brain, the idea that the mind is associated with an immaterial essence, spirit or soul has an extension, namely that this soul may somehow outlive the body and be said to be immortal. If there were strong evidence of some form of life after death then this would certainly argue strongly against the sufficiency of neuroscientific materialism. Rather depressingly, no such evidence exists. It would be lovely to think we could live on after our body dies and be reunited with loved ones who have died before us. Unfortunately, wishful thinking does not constitute evidence.

Of course, there is no scientific evidence that there is not life after death, but should we expect neuroscience to have to refute this alternative hypothesis? Actually, the idea that there is something non-physical at our essence is non-refutable – no matter how much evidence we get from neuroscience, it does not prove this hypothesis is wrong. What neuroscience does say is that it is not necessary and has no explanatory power – there is no need of that hypothesis.

18 comments:

  1. Your discussion of self-awareness reminds me of an idea that I first encountered, I think, from Asimov. In some of his stories, future scientists are constructing models of the universe in order to predict future events. They of course discover that a perfect model would contain every single variable, all matter and energy, and therefore would effectively *be* a universe, and would have to occupy the same amount of space as the actual universe.

    Similarly in our brain, we cannot allocate enough physical resources to have a complete awareness of our own consciousness. We have a simple model, labelled "me". There are parts within the brain which we just cannot model. The "subconscious" mind, thoughts and processes that we can't access or analyse, is not necessarily completely inaccessible, however. We can still understand the physical (chemical, electric) processes, and gradually build the model in the scientific literature, instead of inside our brains!

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  2. Some good points. Personaly, I was convinced of everything you say here when I read Crick's "Astonishing Hypothesis".

    Each region of, at least, the neocortex is an analog computer that potentially can perform a transform of an incoming signal representing a scalar value mapped over an n-dimensional space into an output signal of the same type. Set three or more of these into a closed loop, and you have the potential for an animal to be aware of its own mental state in the same way that it's aware of its environment.

    In fact, it can be aware of the integrated results of its own awareness with the changing state of the environment with a delay of one passage round the closed loop, say 30 ms.

    If you assume the 6-layered neocortical structure is required for such closed loops, you could probably point the beginning of such self-awareness to sometime in the Permian, although T. S. Kemp would assign it to the earliest mammals. (You would need to explain the appearance of awareness in birds: perhaps the wulst performs a similar function.)

    Personally, I suspect that the 3-layered structure of the paleocortex would be sufficient for such closed loops, and primitive self-awareness began with the earliest vertebrates.

    However, there is an aspect of the human personality that isn't explained by all this. Experiments with twins have suggested that around 50% of the personlity is inherited, while perhaps 10% is due to parental influences. The rest remains unexplained, although it might be explained by random factors in the developing brain (analogous to fingerprints) or perhaps the influence of peer-group experiences. Nevertheless, it might also constitute a "soul" infused into the body during prenatal development, and even perhaps transmigrated.

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  3. red, that's a really interesting idea - that to intuitively understand our own consciousness on a personal level would require our building a mental model of equal (or greater) complexity. Better to do it as a collective scientific enterprise!

    AK, I agree that there are good models for how self-awareness can emerge from interlocking loops, enabling metacognition in humans (and some forerunners of it in lower animals). I don't see your point about the twin studies though. My own viewpoint, which I have discussed here before, is that the unexplained variance between twins arises largely from stochastic developmental variation in how the brain is wired. I.e., the same substrate - differences in brain wiring - but a different, non-genetic and also non-environmental cause.

    (See: http://wiringthebrain.blogspot.com/2009/06/nature-nurture-and-noise.html, and also: http://wiringthebrain.blogspot.com/2011/05/somatic-mutations-make-twins-brains.html)

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  4. Hooo... I was waiting 'till the end for a killer new reference that would bring new insights on the matter !

    The dream in creating a brain in silico would be to be able to freeze its mental state and rewind to the processes of how it got there. I believe researchers at IBM are trying to model a working cortex in collaboration with Universities and the DARPA (http://www-03.ibm.com/press/us/en/pressrelease/28842.wss). They claim to be able to model something approaching the size of a cat cortex !

    However, considering what's been said here, it is very likely that if by the use of mutating algorithms we could achieve that level of complexity, it will be out of our reach to understand how we got it working in the first place!

    Also, you are right to point out that metaphysical explanation of the mind are indeed beyond science, and scientists shouldn't bother to even try arguing with their supporters.

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  5. Sorry Nicolas, no new reference, no new data - not much original thought in fact! I wrote this because I was struck, in giving various public talks, that the starting point for neuroscientists was so far removed from that of the majority of the general public. And most people are not very receptive to the idea that their "selves" simply emerge from the activity of a few pounds of electric meat. Many find the idea offensive actually, though it doesn't have to be. (And whether it's offensive or not has no bearing on its accuracy).

    I don't think we shouldn't bother trying to argue the point, however - I just think the argument should be framed differently - not as the theory of neuroscientific materialism versus religious or spiritual ideas, as if they are on an equal footing - that is like pitting evolution against ID. One theory has a massive amount of scientific data behind it and the other has, well... not a lot, to be frank.

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  6. I enjoyed your article and I do agree with Red's Asimov reference. But I don't think that the way you wish to re-frame the material/spiritual argument is at all helpful - I think to transcend such dualistic thinking is what is called for (I speak here, as a budding scientist, an experiencer of zen and master of neither). Often, I have found, that the the people arguing are not even referring to the same thing!
    Take for example 'consciousness', the concept bandied about by both. The consciousness neuroscientific circles are referring to, is consciousness of the self. You are entirely right - there is no questioning, that this 'emerges'as a pattern, a construct (and as such IS immaterial, adding to the confusion) and that this is not possible with out the integration and organisation occurring in the material brain (specifically the left hemisphere). Consciousness thrown around in spiritual circles is usually referring to consciousness of the whole/connection with something 'bigger', more than just our flesh etc. This is not un-scientific, it is actually the state of no-self experienced when attention is lateralised in the right brain but definitely another story.

    Back to the idea that both sides of the argument are missing things. Spiritual types aren't aware of the concept of self organisation which occurs without any "ghost in the machine". They are misguided in thinking it's required. But do have a point in arguing extreme reductionism - as it seems some scientists don't live by the tenets of non-linear dynamics - we ARE more than the sum of the parts/circuitry. We cannot reach understanding of the whole/brain/self etc by looking at parts in isolation, as biological systems operate on a different level to linear cause and effect.
    Another hang up I have is the way mind and soul are thrown together in one basket. Spiritual people with any credibility (and sadly yes, that's few) do not consider these the same thing at all. Soul in more eastern traditions, is not housed in the brain. The conclusion I have come to is that this said soul is not material and is does exist separate from the body. Sounds absurd but I think it may be more like a blueprint/a constraint guiding self organisation (existing as a frequency/energy~electrical field like the embryonic field). For those existing before understanding of technology, energy, emf etc probably would have been thought of as some mysterious essence.

    Anyway I guess the main idea I wanted to impart is that to disregard one side of the other is not helpful, and without a thorough understanding of both, possibly ignorant. Iv'e become increasingly frustrated with both sides from my readings lately and do sincerely apologise for leaving such a slightly off topic and more than likely incoherent/incomplete (possibly related to the large glass of red wine beforehand) rant, on your generally well informed and definitely well written and interesting blog! cheers and thanks.
    ~never stop questioning your assumptions~

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  7. The amount of physical space our brain occupies has so much to due with how enriched/impoverished the environment is that comparing it to a computer has serious discrepancies. The incoming signal of a computer doesn't build the computer. This is where the hardware/software analogy falls short. As for the twin studies I think the homogeneity of the adoptive environment leaves out so much of the diversity that is essential for any real understanding.

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  8. For a wonderful take on the idea that our sentient selves may emerge from the workings of our physical bodies, this Mind Hacks blog links to an audio recording of a short story by Terry Bisson entitled "They're made out of meat":
    http://mindhacks.com/2011/07/07/theyre-made-out-of-meat/

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  9. Sorry Nicolas, no new reference, no new data - not much original thought in fact!

    I don't recall seeing a discussion of this paper (although I may have missed it). And you could always go back and take another look at Jaynes' Origin of Consciousness in the Breakdown of the Bicameral Mind. IMO many of the implications of his suggestions have been neglected in modern neurology.

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  10. briefly: thanks for the article, it's the clearest short summary of the position I can remember reading. cheers! Andi

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  12. Interesting post! Reading this I realize that I'm not an Android lol. Thanks for posting this. Keep working hard on this site!
    3tabs

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  13. I like to refute this its not true there is no scientific evidence for mind being independent from the brain. There is a lot of such evidence from psi phenomena under very tight strict controls as well as evidence for life after death from the cross correspondences, near death experiences etc. I am sure your not aware of them because your not necessarily interested in what psychical research and parapsychology and quantum physics has to say. However, If you are interested their is a book out called the Irreducible Mind: Toward a Psychology for the 21st Century you may want to check out.

    http://www.amazon.com/Irreducible-Mind-hard-find-contemporary/dp/0742547922

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  15. It is a Copernician revolution. As the earth is trivial in the universe, so our self and subjective experience are meaningless (mainly) also. Ho hum...

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  16. Oh yeah, a good extended discussion of this issue is at www.whyevolutionistrue.com. Search free will

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  17. "What neuroscience does say is that it is not necessary and has no explanatory power – there is no need of that hypothesis."

    This is a very absurd statement. You realize what you're saying ? You say: "Because all the colors that I see don't explain anything, they don't exist." Which is of course, an absurd statement, given the fact that... hey... the colors actually exist.

    I don't say there is a soul that would survive death. I'm saying that qualia are something more than the mere activity of our brain. They may even be entirely generated by the brain, but still, they are something more. They are telling us about some fundamental principles in physics. And these unknown principles may well have a greater influence in other areas of physics as well. As long as merely analyzing some circuits in the brain, we unexpectedly obtain something more (qualia), then what if when we do Newtonian mechanics, we also get something more ? Something we don't yet know.

    And there is also the apparent intervention of qualia in determinism. Think about it. The reason that I am writing this post now, is the very fact that I have qualia. If I wouldn't have qualia, I would not care about talking about them. For example: First I see red color, and then I ask: "What is red color ?" If there would be no red color, if there would be only the brain activity in response to electromagnetic radiation of a given wavelength, then I would see no red color, and I would not ask the question: "What is red color ?" So, how do you explain this ?

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    Replies
    1. I like the fact that you exemplify one of the issues I mentioned in this post: http://www.wiringthebrain.com/2013/03/genes-brains-and-human-nature-joys-and.html - "I occasionally get comments starting, “So, what you’re really saying is…”, which continue to say something I really wasn’t saying."

      I don't deny the "existence" of qualia, as states of the mind (not as objects in the world, as you seem to suggest colours are). We cannot currently explain how they come about or why it feels like something to experience them. This does not mean we need to invoke something supernatural - all the evidence still indicates they arise from brain activity.


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