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Do you know what sensations you’re having?

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Last week, Matt Lieberman posted the video below on Twitter. (I believe it was originally posted on TikTok by the dancer featured in it.) The video illustrates change blindness. Large visual changes occur during the course of the video, which the viewer typically doesn’t notice. You may like to watch the video a few times and see if you notice the changes.

If you still haven’t noticed the changes, I’ll tell you. [Spoiler follows]

. . .

The colours of the dancers’ tops change markedly during the video. You can see the difference easily by jumping to different points in the video and noting the colours of the tops at each point.

You may be surprised that you missed such a large change, but it is not really surprising. Our visual systems are designed to keep track of things through changes in their appearance. Imagine you’re in a forest with a tiger stalking you. As the tiger moves in and out of the shade, the light reflected from its coat changes continually, but you need to ignore these changes and focus on what’s constant: the individual animal moving through the trees. And that is exactly what your brain does. In the case of the video, your brain accurately tracked the individual dancers, not confusing one with another, and it ignored changes in colour that were irrelevant to this task. Looked at in this way, change blindness is not a bug in our visual system but a feature, and we should expect it to occur all the time.

But this feature of vision presents a problem for a certain view of consciousness, which I’ll call the three-stage view. The view goes like this. Conscious perception proceeds in three stages. First, physical stimuli impact on our sense organs and produce neural activity in sensory processing regions of our brains. Second, this neural activity produces a visual sensation — a private mental quality which makes it like something to perceive the stimuli. Third, the sensation in turn produces reactions appropriate to its nature (unpleasant sensations cause us to shun the things generating them, pleasant sensations cause us to seek them out, etc). We react as we do because of what our experiences are like.

Now, when the colours changed without your noticing it, what happened at each of the three stages? There were certainly changes at the first stage. The light rays hitting your retina changed, and, presumably, at least some of the activity in your visual cortex did, too. There were no changes at the third stage, however — or at least no major ones. Maybe there were subtle changes in your behavioural dispositions that could be detected under experimental conditions. (I don’t know if this has been investigated; it would be an interesting project.) But your reactions did not change in a way that was noticeable either to you or to a casual observer.

What about the second stage? Did your visual sensations change? Was there a change in what the experience was like for you?

If there wasn’t, then the three-stage view is undermined. For it says that our reactions are produced by our sensations; we react as if there is something green in front of us because we are having a sensation of green. But if we don’t have such a sensation until we react, then the sensation can’t be playing this role. Indeed, it not clear why we would need sensations at all, since the reactions occur without them.

So a defender of the three-stage view must say that our sensations change before we react. They can then continue to claim that when we do react we are reacting to a change in our sensations, albeit after a delay.

But this has a strange consequence. It means that we can be mistaken about our own current sensations. At the mid-point of the video, you thought you were having the same colour sensations as at the start, but you were in fact having different ones. And does that even make sense? Your sensations are supposed to define how things seem to you, and while you may be wrong about what colour something is, you can’t be wrong what colour it seems to be.

That’s not all. If you can fail to notice your sensations changing, then maybe you could fail to notice them fading out altogether. Maybe your sensations faded out an hour ago, and you haven’t noticed yet. You’ve continued to react as if they hadn’t faded out, of course, but during the video you continued to react as if your colour sensations hadn’t changed. Maybe you’ve never had colour sensations at all. Maybe you’re just reacting as if you have them. How do you know? All you can be sure of is what you think about your sensations. Maybe sensations are a sort of illusion.

A confession

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I have a confession to make. I often fail to reply to people who email or message me with invitations, requests, and questions. I have an excuse, of sorts. I have many demands on my time and haven’t been in the best of health. But I feel guilty about it.

I am particularly bad at replying to messages that pose philosophical questions. Replying to such a message takes time and thought — especially if the question is a good one — and I often put it off, though fully intending to reply at some point. And then, of course, more messages come in, and my to-reply list grows longer and longer. The senders must think I am just ignoring them.

Why don’t I at least send a short acknowledgement, saying that I have received the message and will reply if and when I have time? I have thought of doing this, but the danger is that it would make me even less likely to write a full reply. Having sent the acknowledgement, I might feel that I’d dealt with the matter and could forget it. By contrast, If I don’t reply at all I feel guilty, and the guilt does sometimes push me to reply properly.

So here’s a message to anyone who has written to me and not received a reply:

First, I am sorry; please accept my apologies.

Second, please don’t think that I felt your message wasn’t worth a reply. The chances are it was just the opposite: I felt that it deserved a long and careful reply, which I just didn’t have time to write.

Third, please feel free to re-send your message. I won’t be annoyed and will reply eventually!

Zac’s disappearing nonconsciousness

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Clive Wearing is a former musicologist and musician who has chronic amnesia, both anterograde and retrograde. He can’t form new memories or retrieve old ones. Although he is fully conscious, Clive lives trapped in a perpetual present, with no awareness of his own past (according to Wikipedia his episodic memory has a capacity of only 30 seconds). He continually feels that he has just emerged from a long period of unconsciousness, and in his diary he repeatedly affirms that he is now at last awake, scoring out earlier entries which affirmed the same and which now mean nothing to him:

8:31 AM: Now I am really, completely awake.
9:06 AM: Now I am perfectly, overwhelmingly awake.
9:34 AM: Now I am superlatively, actually awake.

Clive’s condition is a personal tragedy for him and his loved ones, but it is a also a fascinating psychological case study, and I want to take it as the basis for a philosophical thought experiment. I hope this does not suggest any disrespect to Clive or his family. I certainly intend none.

Clive suffers from what we might call disappearing consciousness. At every waking moment he is fully conscious, but those conscious moments rapidly pass into oblivion, and Clive’s conscious life has a brief temporal extension. We can imagine his memory span reducing further — to twenty seconds, ten, one, less — until his conscious life is the merest flicker in an otherwise dark existence.

I want to imagine someone who is the inverse of Clive — someone who suffers from disappearing nonconsciousness. Consider Zac. Zac has suffered an illness which has left him a zombie in the philosopher’s sense. His brain functions exactly as it did before, taking in the same range of sensory information and using it to produce responses just like those of a fully conscious person. He can give detailed reports on the world around him and his own bodily condition, noticing everything a fully conscious person would. However, his brain no longer produces any subjective experience — his mental states no longer have any phenomenal feel to them, no ‘what-it-is-likeness’. The inner light of phenomenal consciousness has gone out, and Zac experiences the world unconsciously. Given the standard way of thinking of consciousness, this should be at least conceivable.

There is a twist, however. Zac is not a complete zombie. Unlike other philosophical zombies, he is aware that he is not phenomenally conscious. So when he describes the visual scene before him, he adds that he isn’t really seeing it. He knows what the world is like, but his experience is not like anything. If zombies are conceivable, then a partial zombie like Zac should be, too. (I have borrowed the notion of a partial zombie from Allin Cottrell, who uses it to question the conceivability of zombies. See his excellent paper ‘Sniffing the Camembert’.)

Zac’s lack of phenomenal consciousness troubles him, and he repeatedly notes it in his diary. (He can write perfectly well, of course, and is aware of what he is writing, though the experience of writing is not like anything for him.)

8:31 AM: Now I am really, completely unconscious.

So Zac is unlike Clive in not being conscious. He is unlike Clive in another way, too. Whereas Clive’s brain fails to record memories of being conscious, Zac’s brain keeps fabricating them. When it forms episodic memories of scenes and events, it tags them as having been experienced in the normal way, just as they were before Zac’s illness. So although Zac experiences the world unconsciously, he remembers it has having been experienced consciously.

The upshot is that Zac suffers from the opposite delusion to Clive. Whereas Clive continually feels that he is waking up into consciousness and denies his past consciousness, so Zac continually feels that he losing consciousness and denies his past nonconsciousness:

8:31 AM: Now I am really, completely unconscious.
9:06 AM: Now I am totally, overwhelmingly unconscious.
9:34 AM: Now I am fully, actually unconscious.

And as the latency period between experience and memory shrinks, Zac’s sense of nonconsciousness shrinks too, until it is a mere flicker of darkness in an otherwise illuminated life.

What is the moral of this? The obvious one is that even if our experiences do have a subjective phenomenal feel to them, this feel may play little or no role in generating our sense of being conscious — of its being like something to be us. So maybe consciousness doesn’t have much to do with phenomenal feel after all.

Designed for destruction?

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Suppose that our universe is intrinsically special in a way that it would not have been if the physical constants had taken other possible values. (As I argued in this previous post, it’s important that it be intrinsically special, not just special in the eyes of the creatures who inhabit it.) Then this would seem to raise the credence we should give to the hypothesis that the constants were not randomly set but shaped by a purposive agency of some kind, which sought to produce a universe with this special feature. For the sake of argument, let’s grant that it does.

So is our universe intrinsically special? What might be the special-making feature be? An obvious candidate is life. Life looks pretty special, perhaps even intrinsically valuable. Now, I’m not convinced that life is intrinsically valuable in the relevant sense. (We often treat it as intrinsically valuable, of course, and it’s right that we do, but that’s another matter.) But let’s concede it. And life certainly could not have existed if the physical constants had not been within a vary small range. So we have an argument that a life-seeking agency shaped our universe to enable to it to support life. Cool!

But wait a minute! Our universe’s physical laws and constants may allow life to emerge, but they also condemn life to complete annihilation. The second law of thermodynamics secures that. The relentless growth of entropy, which actually drives the local development of complexity, will eventually dismantle all complexity, leaving the universe a cold, dead realm of undifferentiated low-energy soup. This doesn’t look like something a life-seeking agency would build in. If we were designing a giant spaceship to carry humanity to a new star system, we wouldn’t build in a self-destruct mechanism set to trigger automatically halfway through the voyage.

In fact, a more plausible hypothesis is that the special making feature is the destruction of life, and that the agency that shaped the constants was seeking this goal — an inference not dissimilar to that drawn by Gloucester in King Lear:

As flies to wanton boys are we to th’ gods,
They kill us for their sport.

A defender of the life-agency hypothesis might reply that the agency could only do so much. It could tweak the physical constants but couldn’t change the second law. But what reason do we have to think that? We know nothing of this agency and the constraints under which it operated. (Unless of course, we think that revealed religion provides such information.) The agency has been introduced simply in order to explain why the universe supports life on the assumption that life is what makes this universe intrinsically special. If the universe is not really so special in the life department, then we can’t save the life-agency hypothesis by saying that the life agency did its best. It’s begging the question. We need to identity the special-making feature independently of the process posited to explain it.

Notes on emergence

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Last April, Bryce Huebner and I had a Twitter exchange about emergence in biology. I felt that we were talking past each other and tried to work out how it had happened. I suspected that it was due to the way the concept of emergence had been used in different traditions, and I sketched the following tentative history. (I should stress that this is speculative; I’m not a historian.)

1. Late 19th – early 20th century: Some British philosophers (Broad, Lloyd Morgan, Alexander) started using ’emergentism’ to describe a metaphysical view on which the world is radically layered, with new fundamental properties and powers spontaneously appearing at each level, building up to the mental.

2. Mid 20th century: That kind of emergentism was empirically falsified, and philosophers rejected it. However, dualist philosophers continued to claim that some mental properties and powers are fundamental, emerge spontaneously, and exert a ‘top-down’ influence on the physical world, causing particles to behave in ways that physics alone could not predict.

3.Late 20th century: Scientists adopted the term ’emergence’, ignoring its metaphysical baggage and using it in a different sense to characterize global features of complex systems, especially self-sustaining ones. Confusingly, these scientists often spoke of these global features as exhibiting a ‘top-down’ causal influence — meaning that the components of complex systems are causally sensitive to global conditions, not that global features appear spontaneously and exert a fundamental causal influence on the physical world, additional to that of the components.

5. Late 20th – early 21st century: To capture the difference between the philosophical and scientific uses, philosophers drew a distinction between strong and weak emergence. However, they tended to define weak emergence in terms of deducibility and denial of ‘top-down’ influences, which made scientists think that that ‘weak’ emergentists denied the kind of global influences they needed to talk about.

6. Same time: Some dualist philosophers seized on this, claiming that scientists themselves were now talking of strong (spontaneous, fundamental) emergence. If strongly emergent features are common in the natural world, then why shouldn’t aspects of the mind be strongly emergent? Science vindicates dualism!

7. April 2021: Bryce and Keith talk past each other, Bryce adopting the scientific use, Keith the philosophical one.

At the time, Bryce and I talked of writing this up as a short paper, which we may still do. Meanwhile, if anyone has any comments, I’d be grateful for them. Comments from historians of science and philosophy would be particularly welcome!

Illusionism cover image

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Front cover of Illusionism book

The cover image for my 2017 book Illusionism as a Theory of Consciousness is a painting of a rather flamboyant stage magician performing a variety of tricks simultaneously. I found the image on Wikimedia and thought it was an appropriate visual metaphor for the theory discussed in the book. But who was this magician? Wikimedia says only this about the image:

Zan Zig performing with rabbit and roses, including hat trick and levitation. Advertising poster for the magician (who seems to have left no other trace behind).

Could it be Julius Zancig? It seemed unlikely to me, given the description of Julius’s act, which he performed with his wife Anges. I put a message on my website asking if anyone could find out more.

In 2020, Jeff Miner (a former student of Kent Bach at SFSU, now working in tech) contacted me to say that he’d done some research on the image, which he has kindly given me permission to share. Jeff wrote:

I asked around and crowd-sourced a bit.

It looks as though he was a magician (possibly from the Cincinnati area) who named himself in such a way as to be confused with Zancig.

There’s a second lithograph of him at the LoC.

This response I got seems the most complete:

It was fairly common for second and third rank magicians to use names that resembled those of first-rank magicians (e.g. Hoodini, Howdini, Houdyni, etc.). The Zancigs, (Agnes and Julius) toured with a two-person telepathy (second sight) act. They didn’t do bunnies, doves and goldfish. It’s possible there was a fellow who called himself “Zan Zig” in hopes that people would think they were seeing the Zancigs.

Since the US Copyright Office is part of the Library of Congress, and since this lithograph was copyrighted, I expect the LOC got the name from the copyright registration. Librarians are pretty good about researching items in their collections, and the LOC librarians are some of the best in the world.

As to who “Zan Zig” might have been, at least on the Google-Indexed Web all hits on “Zan Zig” are to this picture (or the second lithograph also at the LOC showing a fellow who looks like the same guy doing four different illusions.) The fellow top left in that second lithograph is the standard stage version of Mephistopheles from Faust.

Doing a search in The New York Clipper and the New York Dramatic Mirror for the year 1899 might reveal more, or maybe not if this fellow was a local Cincinnati magician.

In a second email, Jeff forwarded further information from one of his correspondents:

There was a magician of this period named “Zanzic,” He was referred to in Leaves From Conjuror’s Scrapbooks, with this paragraph:

Another magician by the name of Robinson has been traveling in the Western States for the past few years, but is going under the professional name of Zanzic. Being a clever performer, it would seem he ought to have originated a more healthful-sounding name, which is “sick’led o’er with a pale cast of thought.”

There is quite a bit more about him in Jim Steinmeyer’s book The Glorious Deception, pages 135-138. The first paragraph there reads:

Zanzic was a tall, slender, dark-haired magician. His real name was Robertson or Brenner, and he also worked under the name Henry Andre. Zanzic had been born in New Orleans, the son of a Creole fortune-teller. He was six years younger than Will [Robinson], an old friend from the days when they were both starting out in magic and used to meet at Martinka’s shop. His associates thought of Zanzic as unstable: accident-prone and filled with half-baked schemes. He certainly had the skill to be a good magician. But for Zanzic, the adrenaline of a performance was like a strange, addictive sort of poison that made him giddy and stupid.

In short, the illustration is of a hyperactive magician who was hoping to deceive people about his very identity. I think that makes it even more appropriate for a book about the addictive self-illusions our brains create.

The title of this blog

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The title of this blog, Tricks of Mind, reflects the role that notions of illusion and artifice play in my view of the human mind. We humans have learned a variety of subtle but powerful tricks — strategies of self-control, self-manipulation, and extended problem-solving — which vastly extend the power of our biological brains and give us the sense of having a unified, phenomenally conscious mind, self, or soul. The conscious mind is a virtual system, constituted by these activities. It is, in a sense, a trick of the biological mind.

The pinprick solution to the Fermi paradox

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Why are there no signs of aliens, given the vastness of the galaxy and the apparent abundance of opportunities for life to develop? This is the Fermi paradox. Here’s a possible solution to it. I’ve not seen it proposed before, though I don’t know the literature well.

Suppose the following claims are true:

1) There is a multiverse. (It may not be strictly necessary to assume this, but it makes exposition easier.)

2) Any universe that is capable of supporting life is also fragile, in the sense that a relatively small, highly localized ‘pinprick’ event can cause the whole thing to collapse, as a pinprick can destroy an inflated balloon.

3) ‘Pinprick’ events do not occur naturally. (Again, it may not be strictly necessary to assume this.)

4) An advanced technological civilization will almost certainly create a pinprick event inadvertently as soon as it is capable of doing so. (Suppose that there is a technological process that promises huge benefits in say, in cheap energy or interstellar travel, but which will also, and unforeseeably, create a pinprick event.)

Then we have a solution to the Fermi paradox. Every universe in which a technological civilization develops is rapidly destroyed by that civilization — or by another that develops around the same time. No universe contains more than a very small number of technological civilizations, and we shouldn’t expect to see signs of another one in our galaxy.

And we’re going to destroy the universe soon.

Fine-tuning and intrinsic value

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I’ve been thinking a bit about the fine-tuning argument for design, and in particular about this Scientific American piece by Philip Goff. I’ve also been talking to Philip about it. Here are few thoughts arising from the process.

(Note added 8/11/21: Below I talk about fine-tuning as evidence for design — a word which might be taken to imply the existence of a personal creator god of the kind believed in by the Intelligent Design community. Philip has asked me to clarify that he does not align himself with that community and that he prefers to talk of fine-tuning as evidence for ‘teleology’ or ‘goal-directed activity’ in the early universe rather than design. The points made below equally to this weaker claim.)

The fine-tuning argument starts with the uncontroversial claim that if the fundamental physical constants of our universe had been different, then life would have been impossible. There is only a tiny range of possible values within which stable complex physical structures, and hence life, could arise. That is, it looks as if our universe has been designed to support life. More precisely: given the evidence (the actual nature of the constants — call this E), the hypothesis that the universe was designed (D) is more probable than the hypothesis that it arose by chance (C). Schematically, Pr(E/D) > Pr(E/C).

One reply to this is that is there is another, equally probable, hypothesis — namely, that there is a multitude of universes (a ‘multiverse’), each member of which has different constants. Our universe was not specially designed for life; it just happens to be one in which life is possible. It seems special to us because it enabled us to exist. Compare a lottery winner who thinks there must have been something special about their ticket. There wasn’t really anything special about it. It seems special to them because it made them a winner. It doesn’t seem special to anyone else, and our universe doesn’t seem special from other perspectives either.

I think Goff would agree that if there were a multiverse, then the existence of our universe would be no more improbable than if there were a designer. But he argues that the existence of our universe does not make it probable that there is a multiverse. To think it does, he argues, is to commit the reverse gambler’s fallacy (the fallacy that an observed lucky throw of the dice must have been preceded by long series of unobserved unlucky ones). To underline the point, he describes a scenario in which a deranged kidnapper will kill you unless a certain monkey types out an English sentence within a set time (an analogy for the universe having just the right constants for us to exist). Goff points out that if the monkey comes through with the goods and you survive, you won’t be tempted to infer that there are lots of other typing monkeys around, on whose productions the lives of other, less fortunate, victims depend (analogous to a multiverse).

The issues here are tricky, and I don’t claim to be clear about them. But even if Goff is right about the multiverse hypothesis, I don’t think the result is a win for the design hypothesis. For the obvious alternative to the design hypothesis is a simpler one: that our universe arose by chance, with random constants (analogous to the monkey just happening to type English). Our universe had to have some constants, and they just happened to be ones that made life possible. It seems amazingly lucky to us, of course, but that is because we are living beings and wouldn’t be around if the constants had been different. The specialness is in our eyes only — analogous to the specialness of the lottery’s winner’s ticket. Why is this hypothesis less probable than the hypothesis that the universe was designed to support life? Why should we think that a designer tuned the constants to make our existence possible, any more than a lottery winner should think that someone fixed the lottery to make them win?

Now we can easily imagine a case where design would be more probable than chance. Suppose our universe had some feature that made it objectively special, not just special in our eyes. Suppose that, in virtue of having the constants it has, it supported something intrinsically valuable, which a universe designer would plausibly want to promote. Then, other things being equal, design would be more probable than chance. Analogously, if there were something about the lottery winner that made their winning independently significant — say, that they were married to the chief executive of the lottery company — then we would be warranted in suspecting that the lottery had been fixed. Proponents of the fine-tuning argument can claim that this is in fact the case, and that life is the specialness-conferring feature.

In short, the fine-tuning argument requires the assumption that life itself, or the experiences of living beings, is intrinsically valuable. (This is in fact Goff’s view.) This isn’t to say that that the assumption is sufficient for the argument to work — there might be other problems with the argument, particularly with the design hypothesis itself — but it is necessary to get it going.

Should we make the assumption? It is a big issue, but I think not. Of course, life and the experiences of living creatures matter enormously to us, but I don’t see any reason to think they matter in the way required by the fine-tuning argument — that they have an intrinsic value, independent of the interests of living creatures. Indeed, I find it hard to make sense of the claim. As I see it, value and meaning are rooted in the interests of living creatures, even if we sometimes speak of them as intrinsic properties of things. But that’s another story. The moral I want to draw here is that the fine-tuning argument needs the assumption that life is intrinsically valuable.

Introducing jekylls

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Philosophers of mind talk a lot about zombies. I want to introduce a related species of philosophical monster, which I shall call jekylls. Like zombies, jekylls are atom-for-atom duplicates of us, inhabiting a world with the same physical laws as ours — a world which, let’s assume, is causally closed. Your jekyll twin has all the same physical and functional states you do, including mental ones. It has the same functionally defined perceptions, sensations, thoughts, desires, memories, and emotions, and it is conscious in a functional way too. It also has a sense of self, built of memories, emotions, and introspective and interoceptive states — all functionally defined. (For simplicity, I’ll use ‘psychological’ as David Chalmers does in TCM to mean ‘psychological in a functional sense’.)

So far, then, jekylls are just like zombies. There is a difference, however. Jekylls also have phenomenal states, understood as qualitative mental states that can’t be characterized in functional terms. The phenomenal lights are on inside, as they supposedly are in us. But jekylls aren’t just like us, either. For their phenomenal states are not aligned with their psychological ones. There is a deep incongruity between what they are thinking and feeling psychologically and what they are thinking and feeling phenomenally. When they are psychologically calm, they are filled with phenomenal rage, when they are in psychological pain, they feel phenomenal bliss, when they are psychologically confused, they experience phenomenal clarity, and so on. They are phenomenal/psychological self-inverts.

As a consequence, jekylls have dual selves (you see now why I chose the name). As psychological beings, they have no introspective access to their body’s phenomenal states (which have no distinctive effects), and their phenomenal states make no contribution to their psychological sense of who they are. The subject of their phenomenal states — whatever it is — is completely isolated from the self manifested in their reactions, overt and covert. Each jekyll harbours a phenomenal Mr Hyde. (As with zombies, the literary parallel is not exact, since jekylls never morph into hydes; their inner hyde is forever locked away in a metaphysical limbo.)

Are jekylls conceivable? If zombies conceivable, then jekylls are too. We can conceive of zombies because there is no conceptual connection between functional facts and phenomenal facts. And if there no conceptual connection between functional facts and phenomenal facts, then jekylls are conceivable too. If you think that jekylls are not conceivable, then you have a conception of the phenomenal that is not the one employed in the zombie argument.

Now if phenomenal realism is true, then we are like jekylls, except that our phenomenal selves are beautifully aligned with our psychological ones. You, too, have an ineffective hidden self, but it perfectly mirrors the worldly self manifest in your reactions.

But wait a minute! How do you know that aren’t a jeykll — that you don’t harbour an inner hyde? If you are sure you don’t, then there are two explanations. The first is that you identify with your phenomenal self rather than your psychological one, and know that you are not a hyde. Your mind harmonizes perfectly with the psychological mind your brain processes implement. The downside of this option is that you are strangely alienated from the self manifest in your reactions. You are a phenomenal ghost ineffectively haunting a psychological machine. The other explanation is that at heart you identify with your psychological self and don’t really think you have a phenomenal self at all. You are a complex psychological being, and if you are tempted to think you have a phenomenal self as well, that’s due to features of your psychology. The downside of this is . . . you’re an illusionist!

Old poster for Dr Jekyll and Mr Hyde