Do we see reality as it is? | Donald Hoffman | TED

Summary

In this thought-provoking talk, Donald Hoffman challenges the intuitive belief that our perceptions reflect reality as it is. Drawing on evolutionary theory and neuroscience, he argues that our perceptions are not accurate representations but rather adaptive interfaces designed by evolution to enhance survival, not truth. Hoffman suggests that reality may be far more complex and fascinating than our perceptions indicate, opening up new avenues for understanding consciousness and the nature of existence.

Takeaways

• 🧠 The relationship between brain activity and conscious experiences remains a scientific mystery, with the question of how consciousness arises from physical processes still unexplained.
• 🕵️‍♂️ Thomas Huxley noted the correlation between brain activity and consciousness in 1868 but was unable to explain the 'why' behind it, highlighting the longstanding nature of this enigma.
• 🤔 Some experts believe the problem of consciousness is unsolvable due to a lack of necessary concepts and intelligence, comparing it to monkeys not being able to solve quantum mechanics.
• 💡 The speaker is optimistic, suggesting that the mystery of consciousness may be solved by correcting a false assumption in our understanding of perception and reality.
• 👀 The script challenges the idea that we perceive reality as it is, using the example of a red tomato and questioning whether our perceptions accurately reflect objective reality.
• 🔬 Neuroscience reveals that a significant portion of the brain is involved in vision, creating shapes, objects, colors, and motions in real-time, rather than passively recording reality like a camera.
• 🎨 The script presents visual illusions to demonstrate that we construct our visual perceptions, such as seeing a 3D cube from 2D discs or glowing bars from static dots.
• 🧬 Evolutionary theory is discussed, suggesting that accurate perception may not always confer a survival advantage, as illustrated by the Australian jewel beetle mistaking beer bottles for mates.
• 🔧 The speaker proposes that evolution has shaped our perceptions as an interface to guide behavior, rather than to present an accurate picture of reality, comparing it to a computer desktop.
• 🚂 The script argues against the literal interpretation of perceptions, suggesting that objects like trains are not what they appear to be at a deeper level of reality.
• 🌌 The theory of evolution is presented as a tool to challenge our intuitive but potentially false assumptions about the nature of reality, suggesting that what we perceive as physical objects may not be the true cause of our experiences.
• 🔮 The discussion concludes by opening up new possibilities for understanding consciousness, hinting at the potential existence of a reality beyond our perceptions that could be the source of cause and effect.

Q & A

What is the central mystery discussed in the script?

The central mystery discussed is the relationship between the brain and conscious experiences, such as the experience of taste or touch.

What did Thomas Huxley compare the emergence of consciousness to in 1868?

Thomas Huxley compared the emergence of consciousness to the appearance of the genie when Aladdin rubbed his lamp, highlighting its unaccountable nature.

Why do some experts believe we may not be able to solve the mystery of consciousness?

Some experts believe we lack the necessary concepts and intelligence to solve the mystery, comparing our inability to solve this problem to monkeys' inability to solve quantum mechanics problems.

What is the speaker's view on the progress made in understanding consciousness?

The speaker disagrees with the pessimistic view and is optimistic, suggesting that we have made a false assumption that, once corrected, could lead to solving the mystery.

What does the script suggest about our perception of reality?

The script suggests that our perception of reality may not be an accurate representation of how things truly are, and that our perceptions might be more of a construction rather than a direct reflection of reality.

How does the speaker describe the process of vision in relation to a camera?

The speaker describes the process of vision as partly similar to a camera, with the eye functioning like a high-megapixel camera capturing an image. However, the billions of neurons and trillions of synapses involved in vision suggest a more complex process of constructing what we see.

What is the evolutionary argument given for why our perceptions are accurate?

The evolutionary argument is that those ancestors who saw more accurately had a competitive advantage, were more likely to pass on their genes, and thus we, as their offspring, can trust that our perceptions are generally accurate.

How does the Australian jewel beetle example illustrate a flaw in the evolutionary argument for accurate perception?

The Australian jewel beetle example shows that even though the beetles had successfully found mates for a long time, they were misled by man-made bottles that resembled females, indicating that evolution does not necessarily favor accurate perception of reality.

What is the role of 'fitness' in the equations of evolution, and how does it relate to perception?

In the equations of evolution, 'fitness' is a key notion that depends on both the reality of the situation and the organism's state and actions. It suggests that what enhances an organism's fitness may not necessarily reflect an accurate perception of reality.

What does the speaker propose as a metaphor to understand our relationship with reality?

The speaker proposes the desktop interface of a computer as a metaphor, suggesting that just as icons on a desktop represent files without showing their underlying complexity, our perceptions are symbols that guide adaptive behavior without necessarily reflecting the true nature of reality.

What challenge does the theory of evolution present to our understanding of consciousness?

The theory of evolution challenges the intuitive belief that our perceptions are a window to reality, suggesting instead that they are constructs designed to promote survival and reproduction, not necessarily to reflect an objective reality.

How does the speaker address the concern that the theory might undermine our endeavors and ability to seek truth?

The speaker reassures that recognizing a false theory does not halt scientific progress. Instead, it allows for the development of new theories about the nature of reality, and science can continue as usual.

What alternative view to traditional materialism does the speaker suggest regarding the nature of reality and consciousness?

The speaker suggests a view called 'conscious realism,' which posits that reality might be a network of conscious agents causing each other's experiences, differing from traditional materialism that sees consciousness as a product of physical processes.

Outlines

00:00

🧠 The Enigma of Consciousness and Perception

This paragraph delves into the profound mystery of the relationship between the brain's activity and conscious experiences. It references Thomas Huxley's 1868 observation on the enigmatic nature of consciousness arising from brain activity. Despite advancements in neuroscience, the 'hard problem' of consciousness remains unsolved. The speaker challenges the pessimistic view that humans lack the intelligence to solve it, proposing instead that a fundamental assumption about perception might be incorrect. The paragraph also explores the idea that our perceptions may not reflect reality as it is, using the example of how our visual system constructs what we see, contrary to the common belief that vision is a passive recording of reality.

05:01

🐞 Evolutionary Illusions and Perceptions

The speaker discusses the evolutionary perspective on perception, questioning the assumption that natural selection favors accurate perception of reality. Using the Australian jewel beetle's mistaken attraction to beer bottles as a humorous example, the paragraph illustrates how perceptions can be misled. It suggests that evolution may not necessarily select for veridical perceptions but rather for those that enhance survival and reproduction, regardless of their accuracy. The speaker proposes that perceptions are more like interfaces that guide adaptive behavior, rather than mirrors reflecting the true nature of reality.

10:02

🖥️ The Interface Theory of Perception

This paragraph introduces the metaphor of a computer desktop interface to explain the concept of perception as an adaptive tool rather than an accurate representation of reality. The speaker argues that just as desktop icons simplify complex computer functions, our perceptions simplify the complex reality to facilitate survival. The paragraph addresses potential objections to this theory, emphasizing that while we take our perceptions seriously for survival, they should not be taken literally as the ultimate truth. It suggests that our understanding of reality, including our brain and neurons, is a construct without direct causal power, challenging the traditional materialistic view of consciousness.

15:06

🌐 The Radical Implications of Evolutionary Perception

The speaker further explores the implications of the evolutionary perspective on perception, suggesting that our understanding of space, time, and physical objects as the nature of reality is fundamentally flawed. By comparing our perceptions to a 3D desktop, the paragraph argues that these constructs are designed to guide behavior rather than reveal the true complexity of the world. The speaker posits that our perceptions are shaped by evolutionary pressures to be useful rather than truthful, and that this realization opens up new possibilities for understanding consciousness and the nature of reality.

20:09

🚀 The Future of Consciousness Studies

In the final paragraph, the speaker discusses the impact of the evolutionary perspective on the study of consciousness. They argue that recognizing the limitations of our perceptions does not undermine the pursuit of truth or scientific endeavor but rather advances it by discarding false theories. The speaker suggests that while our perceptions may not be shaped by reality, other cognitive faculties like logic and mathematics might be influenced by evolutionary pressures toward truth. The paragraph concludes with an open invitation to explore new theories of consciousness, including the possibility of a reality composed of conscious agents, and a challenge to rethink our most intuitive assumptions about the world.

Keywords

💡Consciousness

Consciousness refers to the state of being aware of and able to think about one's own existence, thoughts, and surroundings. In the video, it is a central theme as the speaker explores the mystery of how our conscious experiences, such as the taste of chocolate or the feeling of velvet, are related to brain activity. The video questions the nature of consciousness and its relationship to physical reality.

💡Perception

Perception is the process by which individuals interpret and organize sensory information to produce a meaningful experience of the world. The video challenges the assumption that our perceptions reflect reality as it is, suggesting instead that evolution has shaped our perceptions as survival tools, not as accurate representations of the true nature of reality. Examples include the visual tricks demonstrated in the video and the evolutionary argument about why we perceive objects the way we do.

💡Evolutionary Theory

Evolutionary theory explains how species adapt and change over time through the process of natural selection. In the context of the video, evolutionary theory is used to argue that our perceptions have been shaped not to reveal reality accurately but to enhance our chances of survival. This is illustrated through examples like the Australian jewel beetle, which mistakenly perceives beer bottles as potential mates, showing that perception is tailored to survival, not truth.

💡Reality

Reality refers to the state of things as they actually exist, independent of perception. The video suggests that what we perceive as reality—such as space, time, and physical objects—might not be the true nature of reality. Instead, these perceptions are likened to a desktop interface, simplifying and hiding the complexity of the real world to guide adaptive behavior. This idea challenges the conventional view that our senses provide a direct window into reality.

💡User Interface Metaphor

The user interface metaphor compares our perception of reality to a computer desktop interface, which simplifies and hides the underlying complexity of the computer’s processes. In the video, this metaphor is used to explain how our perceptions do not show us reality as it is but instead present a simplified version that aids in survival. Just as the desktop interface is not a literal depiction of the computer’s inner workings, our perceptions are not a literal depiction of reality.

💡Natural Selection

Natural selection is the process by which organisms better adapted to their environment tend to survive and produce more offspring. The video discusses natural selection in the context of how it shapes perception, arguing that those who perceive the world in ways that enhance survival, rather than accurately, are more likely to pass on their genes. This challenges the idea that our perceptions are evolved to be accurate representations of the world.

💡Fitness

Fitness in evolutionary terms refers to an organism’s ability to survive and reproduce in its environment. The video explains that fitness depends on the organism, its state, and its actions, and that our perceptions are shaped more by fitness than by an accurate understanding of reality. For example, the video uses the concept of fitness to explain why certain organisms, like the jewel beetle, might misinterpret reality but still thrive, as their misperceptions are aligned with survival needs.

💡Veridical Perception

Veridical perception refers to the idea that perceptions can be true and accurately reflect reality. The video argues against this concept, suggesting that evolution does not favor veridical perception but instead favors perceptions that are useful for survival, even if they are not true. This is demonstrated through evolutionary game simulations where organisms that perceive only fitness, rather than reality, outcompete those with more accurate perceptions.

💡Conscious Realism

Conscious realism is the idea that consciousness is fundamental and that reality is made up of conscious experiences rather than physical objects or spacetime. In the video, this concept is introduced as a potential solution to the mystery of consciousness, proposing that the true nature of reality could be a network of conscious agents interacting with one another, rather than the material world we perceive through our senses.

💡Causal Powers

Causal powers refer to the ability of something to cause effects in the world. The video challenges the traditional view that physical objects, like brains and neurons, have causal powers, proposing instead that these are merely symbols or hacks shaped by evolution. According to the speaker, the real source of cause and effect lies in a reality beyond our perceptions, possibly in the interactions of conscious agents.

Highlights

The relationship between the brain and conscious experiences, such as taste and touch, is a profound mystery in science.

Thomas Huxley's 1868 comparison of consciousness to Aladdin's genie highlights the long-standing nature of this mystery.

Modern neuroscience has advanced our understanding of brain activity but not the link to conscious experiences.

Some experts believe the problem of consciousness is unsolvable due to a lack of necessary concepts and intelligence.

The speaker proposes that the lack of progress in understanding consciousness is due to a false assumption that can be corrected.

The question of whether we see reality as it is challenges our perceptions and understanding of the world.

Galileo's hypothesis that sensory qualities like taste and color reside in consciousness is explored.

Neuroscience reveals that a significant portion of the brain's cortex is involved in creating our visual experiences.

The eye's comparison to a 130-megapixel camera does not account for the complexity of neural activity in vision.

Visual illusions demonstrate that we construct our visual reality rather than passively receiving it.

Neuroscientists argue that our perceptions are reconstructions of an objective reality that exists independently of observation.

Evolutionary arguments are used to suggest that accurate perceptions confer a survival advantage.

The Australian jewel beetle example illustrates how evolutionary adaptations can lead to false perceptions.

Evolutionary simulations show that accurate perception of reality does not necessarily lead to survival advantages.

The theory proposed is that evolution has shaped our perceptions as an interface to guide adaptive behavior, not to reveal reality.

The implications of this theory challenge our understanding of the causal relationship between the brain, neurons, and conscious experiences.

The speaker suggests that reality may be something entirely different from our perceptions, prompting a reevaluation of consciousness.

The idea that spacetime and physical objects are not the fundamental nature of reality is a radical departure from traditional views.

The speaker concludes by emphasizing the importance of questioning our assumptions about reality and the potential for new discoveries.

Transcripts

I love a great mystery,

and I'm fascinated by the greatest unsolved mystery in science,

perhaps because it's personal.

It's about who we are,

and I can't help but be curious.

The mystery is this:

What is the relationship between your brain

and your conscious experiences,

such as your experience of the taste of chocolate

or the feeling of velvet?

Now, this mystery is not new.

In 1868, Thomas Huxley wrote,

"How it is that anything so remarkable as a state of consciousness comes about

as the result of irritating nervous tissue

is just as unaccountable

as the appearance of the genie when Aladdin rubbed his lamp."

Now, Huxley knew that brain activity

and conscious experiences are correlated,

but he didn't know why.

To the science of his day, it was a mystery.

In the years since Huxley,

science has learned a lot about brain activity,

but the relationship between brain activity

and conscious experiences is still a mystery.

Why? Why have we made so little progress?

Well, some experts think that we can't solve this problem

because we lack the necessary concepts and intelligence.

We don't expect monkeys to solve problems in quantum mechanics,

and as it happens, we can't expect our species to solve this problem either.

Well, I disagree. I'm more optimistic.

I think we've simply made a false assumption.

Once we fix it, we just might solve this problem.

Today, I'd like tell you what that assumption is,

why it's false, and how to fix it.

Let's begin with a question:

Do we see reality as it is?

I open my eyes

and I have an experience that I describe as a red tomato a meter away.

As a result, I come to believe that in reality,

there's a red tomato a meter away.

I then close my eyes, and my experience changes to a gray field,

but is it still the case that in reality, there's a red tomato a meter away?

I think so, but could I be wrong?

Could I be misinterpreting the nature of my perceptions?

We have misinterpreted our perceptions before.

We used to think the Earth is flat, because it looks that way.

Pythagorus discovered that we were wrong.

Then we thought that the Earth is the unmoving center of the Universe,

again because it looks that way.

Copernicus and Galileo discovered, again, that we were wrong.

Galileo then wondered if we might be misinterpreting our experiences

in other ways.

He wrote: "I think that tastes, odors, colors, and so on

reside in consciousness.

Hence if the living creature were removed, all these qualities would be annihilated."

Now, that's a stunning claim.

Could Galileo be right?

Could we really be misinterpreting our experiences that badly?

What does modern science have to say about this?

Well, neuroscientists tell us that about a third of the brain's cortex

is engaged in vision.

When you simply open your eyes and look about this room,

billions of neurons and trillions of synapses are engaged.

Now, this is a bit surprising,

because to the extent that we think about vision at all,

we think of it as like a camera.

It just takes a picture of objective reality as it is.

Now, there is a part of vision that's like a camera:

the eye has a lens that focuses an image on the back of the eye

where there are 130 million photoreceptors,

so the eye is like a 130-megapixel camera.

But that doesn't explain the billions of neurons

and trillions of synapses that are engaged in vision.

What are these neurons up to?

Well, neuroscientists tell us that they are creating, in real time,

all the shapes, objects, colors, and motions that we see.

It feels like we're just taking a snapshot of this room the way it is,

but in fact, we're constructing everything that we see.

We don't construct the whole world at once.

We construct what we need in the moment.

Now, there are many demonstrations that are quite compelling

that we construct what we see.

I'll just show you two.

In this example, you see some red discs with bits cut out of them,

but if I just rotate the disks a little bit,

suddenly, you see a 3D cube pop out of the screen.

Now, the screen of course is flat,

so the three-dimensional cube that you're experiencing

must be your construction.

In this next example,

you see glowing blue bars with pretty sharp edges

moving across a field of dots.

In fact, no dots move.

All I'm doing from frame to frame is changing the colors of dots

from blue to black or black to blue.

But when I do this quickly,

your visual system creates the glowing blue bars

with the sharp edges and the motion.

There are many more examples, but these are just two

that you construct what you see.

But neuroscientists go further.

They say that we reconstruct reality.

So, when I have an experience that I describe as a red tomato,

that experience is actually an accurate reconstruction

of the properties of a real red tomato

that would exist even if I weren't looking.

Now, why would neuroscientists say that we don't just construct,

we reconstruct?

Well, the standard argument given

is usually an evolutionary one.

Those of our ancestors who saw more accurately

had a competitive advantage compared to those who saw less accurately,

and therefore they were more likely to pass on their genes.

We are the offspring of those who saw more accurately,

and so we can be confident that, in the normal case,

our perceptions are accurate.

You see this in the standard textbooks.

One textbook says, for example,

"Evolutionarily speaking,

vision is useful precisely because it is so accurate."

So the idea is that accurate perceptions are fitter perceptions.

They give you a survival advantage.

Now, is this correct?

Is this the right interpretation of evolutionary theory?

Well, let's first look at a couple of examples in nature.

The Australian jewel beetle

is dimpled, glossy and brown.

The female is flightless.

The male flies, looking, of course, for a hot female.

When he finds one, he alights and mates.

There's another species in the outback,

Homo sapiens.

The male of this species has a massive brain

that he uses to hunt for cold beer.

(Laughter)

And when he finds one, he drains it,

and sometimes throws the bottle into the outback.

Now, as it happens, these bottles are dimpled, glossy,

and just the right shade of brown to tickle the fancy of these beetles.

The males swarm all over the bottles trying to mate.

They lose all interest in the real females.

Classic case of the male leaving the female for the bottle.

(Laughter) (Applause)

The species almost went extinct.

Australia had to change its bottles to save its beetles.

(Laughter)

Now, the males had successfully found females for thousands,

perhaps millions of years.

It looked like they saw reality as it is, but apparently not.

Evolution had given them a hack.

A female is anything dimpled, glossy and brown,

the bigger the better.

(Laughter)

Even when crawling all over the bottle, the male couldn't discover his mistake.

Now, you might say, beetles, sure, they're very simple creatures,

but surely not mammals.

Mammals don't rely on tricks.

Well, I won't dwell on this, but you get the idea. (Laughter)

So this raises an important technical question:

Does natural selection really favor seeing reality as it is?

Fortunately, we don't have to wave our hands and guess;

evolution is a mathematically precise theory.

We can use the equations of evolution to check this out.

We can have various organisms in artificial worlds compete

and see which survive and which thrive,

which sensory systems are more fit.

A key notion in those equations is fitness.

Consider this steak:

What does this steak do for the fitness of an animal?

Well, for a hungry lion looking to eat, it enhances fitness.

For a well-fed lion looking to mate, it doesn't enhance fitness.

And for a rabbit in any state, it doesn't enhance fitness,

so fitness does depend on reality as it is, yes,

but also on the organism, its state and its action.

Fitness is not the same thing as reality as it is,

and it's fitness, and not reality as it is,

that figures centrally in the equations of evolution.

So, in my lab,

we have run hundreds of thousands of evolutionary game simulations

with lots of different randomly chosen worlds

and organisms that compete for resources in those worlds.

Some of the organisms see all of the reality,

others see just part of the reality,

and some see none of the reality,

only fitness.

Who wins?

Well, I hate to break it to you, but perception of reality goes extinct.

In almost every simulation,

organisms that see none of reality

but are just tuned to fitness

drive to extinction all the organisms that perceive reality as it is.

So the bottom line is, evolution does not favor veridical,

or accurate perceptions.

Those perceptions of reality go extinct.

Now, this is a bit stunning.

How can it be that not seeing the world accurately

gives us a survival advantage?

That is a bit counterintuitive.

But remember the jewel beetle.

The jewel beetle survived for thousands, perhaps millions of years,

using simple tricks and hacks.

What the equations of evolution are telling us

is that all organisms, including us, are in the same boat as the jewel beetle.

We do not see reality as it is.

We're shaped with tricks and hacks that keep us alive.

Still,

we need some help with our intuitions.

How can not perceiving reality as it is be useful?

Well, fortunately, we have a very helpful metaphor:

the desktop interface on your computer.

Consider that blue icon for a TED Talk that you're writing.

Now, the icon is blue and rectangular

and in the lower right corner of the desktop.

Does that mean that the text file itself in the computer is blue,

rectangular, and in the lower right-hand corner of the computer?

Of course not.

Anyone who thought that misinterprets the purpose of the interface.

It's not there to show you the reality of the computer.

In fact, it's there to hide that reality.

You don't want to know about the diodes

and resistors and all the megabytes of software.

If you had to deal with that, you could never write your text file

or edit your photo.

So the idea is that evolution has given us an interface

that hides reality and guides adaptive behavior.

Space and time, as you perceive them right now,

are your desktop.

Physical objects are simply icons in that desktop.

There's an obvious objection.

Hoffman, if you think that train coming down the track at 200 MPH

is just an icon of your desktop,

why don't you step in front of it?

And after you're gone, and your theory with you,

we'll know that there's more to that train than just an icon.

Well, I wouldn't step in front of that train

for the same reason

that I wouldn't carelessly drag that icon to the trash can:

not because I take the icon literally --

the file is not literally blue or rectangular --

but I do take it seriously.

I could lose weeks of work.

Similarly, evolution has shaped us

with perceptual symbols that are designed to keep us alive.

We'd better take them seriously.

If you see a snake, don't pick it up.

If you see a cliff, don't jump off.

They're designed to keep us safe, and we should take them seriously.

That does not mean that we should take them literally.

That's a logical error.

Another objection: There's nothing really new here.

Physicists have told us for a long time that the metal of that train looks solid

but really it's mostly empty space with microscopic particles zipping around.

There's nothing new here.

Well, not exactly.

It's like saying, I know that that blue icon on the desktop

is not the reality of the computer,

but if I pull out my trusty magnifying glass and look really closely,

I see little pixels,

and that's the reality of the computer.

Well, not really -- you're still on the desktop, and that's the point.

Those microscopic particles are still in space and time:

they're still in the user interface.

So I'm saying something far more radical than those physicists.

Finally, you might object,

look, we all see the train,

therefore none of us constructs the train.

But remember this example.

In this example, we all see a cube,

but the screen is flat,

so the cube that you see is the cube that you construct.

We all see a cube

because we all, each one of us, constructs the cube that we see.

The same is true of the train.

We all see a train because we each see the train that we construct,

and the same is true of all physical objects.

We're inclined to think that perception is like a window on reality as it is.

The theory of evolution is telling us that this is an incorrect interpretation

of our perceptions.

Instead, reality is more like a 3D desktop

that's designed to hide the complexity of the real world

and guide adaptive behavior.

Space as you perceive it is your desktop.

Physical objects are just the icons in that desktop.

We used to think that the Earth is flat because it looks that way.

Then we thought that the Earth is the unmoving center of reality

because it looks that way.

We were wrong.

We had misinterpreted our perceptions.

Now we believe that spacetime and objects

are the nature of reality as it is.

The theory of evolution is telling us that once again, we're wrong.

We're misinterpreting the content of our perceptual experiences.

There's something that exists when you don't look,

but it's not spacetime and physical objects.

It's as hard for us to let go of spacetime and objects

as it is for the jewel beetle to let go of its bottle.

Why? Because we're blind to our own blindnesses.

But we have an advantage over the jewel beetle:

our science and technology.

By peering through the lens of a telescope

we discovered that the Earth is not the unmoving center of reality,

and by peering through the lens of the theory of evolution

we discovered that spacetime and objects

are not the nature of reality.

When I have a perceptual experience that I describe as a red tomato,

I am interacting with reality,

but that reality is not a red tomato and is nothing like a red tomato.

Similarly, when I have an experience that I describe as a lion or a steak,

I'm interacting with reality,

but that reality is not a lion or a steak.

And here's the kicker:

When I have a perceptual experience that I describe as a brain, or neurons,

I am interacting with reality,

but that reality is not a brain or neurons

and is nothing like a brain or neurons.

And that reality, whatever it is,

is the real source of cause and effect

in the world -- not brains, not neurons.

Brains and neurons have no causal powers.

They cause none of our perceptual experiences,

and none of our behavior.

Brains and neurons are a species-specific set of symbols, a hack.

What does this mean for the mystery of consciousness?

Well, it opens up new possibilities.

For instance,

perhaps reality is some vast machine that causes our conscious experiences.

I doubt this, but it's worth exploring.

Perhaps reality is some vast, interacting network of conscious agents,

simple and complex, that cause each other's conscious experiences.

Actually, this isn't as crazy an idea as it seems,

and I'm currently exploring it.

But here's the point:

Once we let go of our massively intuitive

but massively false assumption about the nature of reality,

it opens up new ways to think about life's greatest mystery.

I bet that reality will end up turning out to be more fascinating

and unexpected than we've ever imagined.

The theory of evolution presents us with the ultimate dare:

Dare to recognize that perception is not about seeing truth,

it's about having kids.

And by the way, even this TED is just in your head.

Thank you very much.

(Applause)

Chris Anderson: If that's really you there, thank you.

So there's so much from this.

I mean, first of all, some people may just be profoundly depressed

at the thought that, if evolution does not favor reality,

I mean, doesn't that to some extent undermine all our endeavors here,

all our ability to think that we can think the truth,

possibly even including your own theory, if you go there?

Donald Hoffman: Well, this does not stop us from a successful science.

What we have is one theory that turned out to be false,

that perception is like reality and reality is like our perceptions.

That theory turns out to be false.

Okay, throw that theory away.

That doesn't stop us from now postulating all sorts of other theories

about the nature of reality,

so it's actually progress to recognize that one of our theories was false.

So science continues as normal. There's no problem here.

CA: So you think it's possible -- (Laughter) --

This is cool, but what you're saying I think is it's possible that evolution

can still get you to reason.

DH: Yes. Now that's a very, very good point.

The evolutionary game simulations that I showed were specifically about perception,

and they do show that our perceptions have been shaped

not to show us reality as it is,

but that does not mean the same thing about our logic or mathematics.

We haven't done these simulations, but my bet is that we'll find

that there are some selection pressures for our logic and our mathematics

to be at least in the direction of truth.

I mean, if you're like me, math and logic is not easy.

We don't get it all right, but at least the selection pressures are not

uniformly away from true math and logic.

So I think that we'll find that we have to look at each cognitive faculty

one at a time and see what evolution does to it.

What's true about perception may not be true about math and logic.

CA: I mean, really what you're proposing is a kind of modern-day Bishop Berkeley

interpretation of the world:

consciousness causes matter, not the other way around.

DH: Well, it's slightly different than Berkeley.

Berkeley thought that, he was a deist, and he thought that the ultimate

nature of reality is God and so forth,

and I don't need to go where Berkeley's going,

so it's quite a bit different from Berkeley.

I call this conscious realism. It's actually a very different approach.

CA: Don, I could literally talk with you for hours, and I hope to do that.

Thanks so much for that. DH: Thank you. (Applause)