Is the ultimate nature of reality mental?

Philosopher Wilfrid Sellars had a term for the world as it appears, the “manifest image.”  This is the world as we perceive it.  In it, an apple is an apple, something red or green with a certain shape, a range of sizes, a thing that we can eat, or throw.

The manifest image can be contrasted with the scientific image of the world.  Where the manifest image has colors, the scientific one has electromagnetic radiation of certain wavelengths.  Where the manifest image has solid objects, like apples, the scientific image has mostly empty space, with clusters of elementary particles, held together in configurations due to a small number of fundamental interactions.

The scientific image is often radically different from the manifest image, although how different it is depends on what level of organization is being examined.  For many purposes, including scientific ones, the manifest image, which is itself a predictive theory of the world at a certain level or organization, works just fine.  For example, an ethologist, someone who studies animal behavior, can generally do so without having to concern themselves about quantum fields and their interactions.

But if the manifest image of the world is how it appears to us, how do we develop the scientific ones?  After all, we only ever have access to our own subjective experience.  We never get direct access to anything else.

The answer is that we start with those conscious experiences, sensory experiences of the world, and we work to develop models, theories, of how those experiences relate to each other.  (We sometimes forget that “empiricism” is just another word for “experience.”  One comes from Greek, the other Latin.)  We judge these theories by how accurately they’re able to predict future experiences.  It’s the only real measure of a theory, or any kind of knowledge, we ever get.

But often developing these theories, these models, requires that we posit aspects of reality that we can’t perceive.  For example, no one has ever seen an electron.  We take electrons to exist because they’re crucial to many theories.  But they’re most definitely not part of the manifest image.

So the theories give us a radically different picture of the world from what we perceive.  Often those theories force us to conclude that our senses, our actual conscious experience, isn’t showing us reality.  The only reason we take such theories seriously, and give them precedence over our direct sensory experience, is because they accurately predict future conscious experiences.

Of course, there are serious issues with many of these theories.  Two of the most successful, quantum mechanics and general relativity, aren’t compatible with each other.  And there’s the measurement problem in quantum mechanics, the fact that everything we observe tells us that there is a quantum wave, until we measure it, then everything tells us there’s just a localized particle.

These are truly hard problems, and solving them is forcing scientists to consider theories that posit a reality even more removed from the manifest image.  It’s why we get things like brane theory, the many worlds interpretation of quantum physics, or the mathematical universe hypothesis.  If any of these models are true, than the ultimate nature of reality is utterly different from the manifest image.

But as stark as the distinctions between the manifest and scientific images are or could be, it’s not enough for some.  Donald Hoffman is a psychologist and philosopher whose views I’ve discussed before.  Hoffman has a new book that he’s promoting, and it’s putting his views back into the public square.  This week I listened to a podcast interview he did with Michael Shermer.

Hoffman’s main point is that evolution doesn’t prepare us to accurately perceive reality.  That reality therefore can be very different than what our perceptions tell us.  But Hoffman is going much further than the typical manifest / scientific image distinction.  He contends that there isn’t even a physical reality out there.  There are only minds.  Our perception of reality is a “user interface” that enables access to something utterly alien in nature.  Even the various scientific images don’t reflect reality.  These are just more user interfaces.

What then is the ultimate reality?  Hoffman appears to believe it’s consciousness all the way down.  In my last post on Hoffman, I labeled him an idealist, in the sense of thinking that the primary reality is mental rather than physical, and I still think that’s the right description.

Although in the Shermer interview, he says he does think there is an objective reality.  Based on what I’ve heard, he sees this objective reality existing because there’s a universal mind of some sort outside of our minds thinking about it, a view that seems similar to the subjective idealism (and theology) of George Berkeley, where objective things exist because God is thinking about them.

How does Hoffman reach this conclusion?  He starts with the fact that natural selection doesn’t seem to favor an accurate perception of reality, just an effectively adaptive one.  He tests this using mathematical simulations which reportedly tell him that there’s zero probability of natural selection selecting for accuracy.

Here we come to my issues with this idea.  Hoffman is using an empirical theory (natural selection) along with empirically observed results of simulations, to conclude that empirical observations aren’t telling us about reality.  But if all of reality is an illusion, then how can he trust his own observations?  In the interview, he assures Shermer that he avoids this undercutting trap, but if so, it doesn’t seem evident to me.

The second issue is that Hoffman is taking this insight and apparently making a major logical leap to conclude that it leads to much more than the manifest vs scientific image distinction.  The established scientific images exist because they’re part of predictive models.  Extending these images to another level requires additional models and evidence, and those models must explain the successes of the previous ones.  Hoffman owns up to this requirement, but admits it hasn’t been met yet.

My third issue is that Hoffman’s stated motivation for positing this idealism is to solve the hard problem of consciousness.  Per the hard problem, there’s no way to relate physics to consciousness, so maybe the solution is to do away with all physics.

But there is an easier solution to the hard problem, one that doesn’t require radically overturning our view of reality.  That solution is to recognize what many psychological studies tell us, that introspection is unreliable, including our introspection of experience.

This too is a sharp distinction between the manifest image and the scientific view.  The problem, of course, it’s that this version isn’t emotionally comforting.  Like Copernicanism, natural selection, relativity, and quantum physics, it takes us ever further from any central role in reality.

Which brings me to my fourth issue with Hoffman’s view.  It’s a radical view that’s emotionally comforting, seemingly positing that it’s all about us after all.  Of course, just because it’s comforting doesn’t mean it’s wrong, but it does mean we need to be more on guard than usual against fooling ourselves.

I’m a scientific instrumentalist.  While I generally think our scientific theories are telling us about reality, I think to “tell us about reality” is to be a useful prediction instrument.  They are one and the same.  There is no understanding of reality which is not such an instrument.

We can’t rule out idealism.  We can only note that any feasible version of it has to meet all the predictive successes of physicalism.  Once it does, it has to then justify any additional assumptions it makes.  It’s not clear to me that we then have anything other than physicalism by another name, or perhaps a type of neutral monism that amounts to the same thing.

But maybe I’m missing something?

Is reality an illusion? If so, does it matter?

Hoffman_1KDonald D. Hoffman, a psychologist at the University of California, Irving, has been getting a lot of attention recently for his views, that evolutionary evidence indicates that reality is an illusion, that the only thing that exists are conscious minds.

This is a modern version of an ancient concept, called idealism.  The earliest writings about it come from the ancient Greeks, although they were almost certainly influenced by the Indian ascetics and sages.

Hoffman’s version is built using ideas of modern science.  He starts with the observation that we aren’t evolved to perceive reality as it is, but in a way that is adaptive, that ensures our survival.  He then brings in quantum physics, noting the often held understanding that consciousness is what causes quantum decoherence (aka wave function collapses).  From this, he deduces that the external world is an illusion, that conscious minds are all that exist.  (This is admittedly a very quick and dirty summation.  Read the articles for a more thorough, and perhaps fairer summary, or watch one of his talks or debates.)

Hoffman has a very valid point about our minds not being evolved to accurately comprehend reality.  This is something that has been understood for a long time.  The idea that we can’t naively trust our perceptions is ancient, and has been well known throughout the history of modern science.  (For example, see Francis Bacon’s Idols of the Mind.)  Reality is not as we perceive it, although it’s a large jump from that common understanding to concluding that reality overall is an illusion.

Image credit: Dhatfield via Wikipedia
Image credit: Dhatfield via Wikipedia

To bridge that gap, Hoffman brings in quantum physics.  To be clear, quantum physics is bizarre.  The more people seem to understand it, the more bizarre it seems to them.  However, Hoffman’s understanding of consciousness causing quantum decoherence might be a bit dated.

Quantum decoherence is now commonly described by physicists to happen from any interaction with the environment.  Only isolated quantum objects, such as individual subatomic particles before they interact with anything (such as hitting the screen in the double-slit experiment), or molecules kept in very isolated laboratory conditions, can remain in a superposition wave state.  In other words, Schrodinger’s Cat either lived or died before the box was opened, since a cat is definitely a noisy system in terms of quantum interference.

This makes sense when you consider why scientists and engineers are struggling to build quantum computers.  Keeping qubits, quantum computing’s version of binary bits, in superposition, preventing them from decohering, is a major challenge.  It’s also why most proto-quantum processors have to operate at near absolute zero temperature, to avoid disturbing the superposition state of the processor’s internals.  If preventing conscious interaction were all that were necessary to prevent decoherence, it seems like these designs could be much simpler.

There’s also the broader difficulty that using sensory experience to conclude that all sensory experience is an illusion, that is, using data from that illusion to conclude it is an illusion, seems problematic.  Of course, someone could say they find logical contradictions or absurdity in that data, hence the illusion conclusion.  But then I have to ask, contradicting what?  Or absurd by what standard?

But, just for the sake of argument, let’s bracket those difficulties, and assume Hoffman is right.  Idealism is true.  One of the other issues I’ve always seen with idealism is that it exempts other minds from this logic.  If everything else is an illusion, what prevents any other minds I perceive to be out there from also being an illusion?  Maybe I’m the only mind that exists.  Or maybe you are and I’m the illusion.  Of course, this is solipsism.  But I’ve  never been able to see what stops idealism from being a logical slippery slope into solipsism.

Furthermore, if we’re going to engage in this kind of skepticism, we can’t even be sure about our own memories.  Maybe everything outside of your mind is an illusion.  Maybe you came into existence 30 seconds ago together with your existing memories.  Perhaps you are in fact a Boltzmann brain, a conscious entity that emerged from random fluctuations a few seconds ago, and will disappear back into those fluctuations in a few more seconds.

All of this is aside from the issue that if reality is an illusion, that illusion appears to exact unpleasant, often painful consequences for not taking it seriously, including consequences for aspects of that illusion we don’t know about, or forget about, or any of the other problems caused by what we normally think of as objective, mind independent reality.

Essentially this makes the illusion our reality, our universe.  And that all the people who insist that there is a reality outside of the universe are right.  We can only hope, if anyone is controlling this illusion, that they’re kindly disposed toward us, or at least not hostile.  The border between this line of reasoning and theology seems like a blurry one.

All of which is to say, if reality is an illusion, then we have little choice but to play the game.  It makes sense to play that game as well as we can, which means understanding it in the most reliable way we can, which brings us back to the methods of science and philosophy for understanding what we commonly call objective reality.

Unless, of course, I have logical holes in my reasoning.

Proof that the external world exists?

Solipsism (Photo credit: Nauman Sadiq)

Eric Schwitzgebel is reading Stannis Lem’s novel ‘Solaris’ and discovers in the novel a test of the existence of the external world:

I instructed the satellite to give me the figure of the galactic meridians it was traversing at 22-second intervals while orbiting Solaris, and I specified an answer to five decimal points. Then I sat and waited for the reply. Ten minutes later, it arrived. I tore off the strip of freshly printed paper and hid it in a drawer, taking care not to look at it…. Then I sat down to work out for myself the answer to the question I had posed. For an hour or more, I integrated the equations….

If the figures obtained from the satellite were simply the product of my deranged mind, they could not possibly coincide with [my hand calculations]. My brain might be unhinged, but it could not conceivably complete with the Station’s giant computer and secretly perform calculations requiring several months’ work. Therefore if the figures corresponded, it would follow that the Station’s computer really existed, that I had really used it, and that I was not delirious (1961/1970, p. 50-51).

This is similar to a test Schwitzgebel describes on his blog.

While these tests are interesting, I don’t see how they conclusively prove that solipsism, the belief that we alone exist and all else is an illusion, is false.  It seems like for any test that we could construct, our very evaluation of that test would be based on sensory inputs, which might themselves be an illusion.  But maybe I’m missing something?

Ultimately, I think we all have to take it on faith that the external world exists.  It certainly doesn’t pay to ignore what looks like the external world, since doing so can cause substantial grief and pain.  Maybe that grief and pain is also an illusion, but I find illusory pain just as…painful as the real thing.