Life 3.0: Being Human in the Age of Artificial Intelligence

by Max Tegmark

It’s this particular definition of consciousness that gets to the crux of all the AI-motivated questions in the previous section: Does it feel like something to be Prometheus, AlphaGo or a self-driving Tesla?

To appreciate how broad our consciousness definition is, note that it doesn’t mention behavior, perception, self-awareness, emotions or attention. So by this definition, you’re conscious also when you’re dreaming, even though you lack wakefulness or access to...

Similarly, any system that experi...

conscious in this sense, even if it can’t move. Our definition leaves open the possibility that some future AI systems may be conscious too, even if they exist merely as software a...

With this definition, it’s hard not to care about consciousness. As Yuval Noah Harari puts it in his book Homo Deus:4 “If any scientist wants to argue that subjective experiences are irrelevant, their challenge is to explain why torture or rape are wrong without reference to any subjective experience.” Without such reference, it’s all just a bunch of el...

David Chalmers,

Then there’s the separate mystery of why you have a subjective experience, which David calls the hard problem. When you’re driving, you’re experiencing colors, sounds, emotions, and a feeling of self. But why are you experiencing anything at all? Does a self-driving car experience anything at all? If you’re racing against a self-driving car, you’re both inputting information from sensors, processing it and outputting motor commands. But subjectively experiencing driving is something logically separate—is it optional, and if so, what causes it?

To me, consciousness is the elephant in the

room. Not only do you know that you’re conscious, but it’s all you know with complete certainty—everything else is inference,

it’s well known that experts do their

specialties best when they’re in a state of “flow,” aware only of what’s happening at a higher level, and unconscious of the low-level details of how they’re doing it. For example, try reading the next sentence while being consciously aware of every single letter, as when you first learned to read. Can you feel how much slower it is, compared to when you’re merely conscious of the text at the level of words or ideas?

The CEO metaphor also explains why expertise becomes unconscious: after painstakingly figuring out how to read and type, the CEO delegates these routine tasks to unconscious subordinates to be able to focus on new higher-level challenges.

Finally, fluorescent voltage sensing involves genetically manipulating neurons to emit flashes of light when firing, enabling their activity to be measured with a microscope. Out of all the techniques, it has the potential to rapidly monitor the largest number of neurons, at least in animals with transparent brains—such as the C. elegans worm with its 302 neurons and the larval zebrafish with its about 100,000.

it’s been discovered that if you make one of your eyes watch a complicated sequence of rapidly changing patterns, then this will distract your visual system to such an extent that you’ll be completely unaware of a still image shown to the other eye.11 In summary, you can have a visual image in your retina without experiencing it, and you can (while dreaming) experience an image without it being on your retina. This proves that your two retinas don’t host your visual consciousness any more than a video camera does, even though they perform complicated computations involving over a hundred million neurons.

NCC researchers also use continuous flash suppression, unstable visual/auditory illusions and other tricks to pinpoint which of your brain regions are responsible for each of your conscious experiences. The basic strategy is to compare what your neurons are doing in two situations where essentially everything (including your sensory

input) is the same—except your conscious experience. The parts of your brain that are measured to behave differently are then identified as NCCs.

Such NCC research has proven that none of your consciousness resides in your gut, even though that’s the location of your enteric nervous system with its whopping half-billion neurons that compute how to optimally digest your food; feelin...

More shockingly, your consciousness doesn’t appear to extend to your cerebellum (figure 8.3), which contains about two-thirds of all your neurons: patients whose cerebellum is destroyed experience slurred speech and clumsy motion reminiscent of a drunkard, but remain fully conscious.

Some recent NCC research suggests that your consciousness mainly resides in a “hot zone” involving the thalamus (near the middle of your brain) and the rear part of the cortex (the outer brain layer consisting of a crumpled-up six-layer sheet which, if flattened out, would have the area of a large dinner napkin).12 This same research controversially suggests that the primary visual cortex at the very back of the head is an exception to this, being as unconscious as your eyeballs and your retinas.

Koch’s summary is that it takes about a quarter of a second from when light enters your eye from a complex object until you consciously perceive seeing it as what it is.13 This means that if you’re driving down a highway at fifty-five miles per hour and suddenly see a squirrel a few meters in front of you, it’s too late for you to do anything about it, because you’ve already run over it!

In summary, your consiousness lives in the past,

with Christof Koch estimating that it lags behind the outside world by about a quarter second. Intriguingly, you can often react to things faster than you can become conscious of them, which proves that the informatio...

uncons...

Indeed, the system that reads that email is continually bombarded with messages from all over your body, some more delayed than others. It takes longer for nerve signals to reach your brain from your fingers than from your face because of distance, and it takes longer for you to analyze images than sounds because it’s more complicated—which is why Olympic races are started with a bang rather than with a visual cue. Yet if you

touch your nose, you consciously experience the sensation on your nose and fingertip as simultaneous, and if you clap your hands, you see, hear and feel the clap at exactly the same time.14 This means that your full conscious experience of an event isn’t created until the last slowpoke email reports have trickled in and been analyzed.

A famous family of NCC experiments pioneered by physiologist Benjamin Libet has shown that the sort of actions you can perform unconsciously aren’t limited to rapid responses such as blinks and ping-pong smashes, but also include certain decisions that you might attribute to free will—brain measurements c...

It makes absolutely no sense to say that a single water molecule is wet, because the phenomenon of wetness emerges only when there are many molecules, arranged in the pattern we call liquid.

So solids, liquids

and gases are all emergent phenomena: they’re more than the sum of their parts, because they have properties above and beyond the properties of their particles. Th...

Now just like solids, liquids and gases, I think consciousness is an emergent phenomenon, with properties above a...

We physicists love studying these emergent properties, which can often be identified by a small set of numbers that you can go out and measure—quantities such as how viscous the substance is, how compressible it is and so on. For example, if a substance

is so viscous that it’s rigid, we call it a solid, otherwise we call it a fluid. And if a fluid isn’t compressible, we call it a liquid, otherwise we call it a gas or a plasma, depending on how well it conducts electricity.

consciousness is the way information feels when being processed in certain complex ways.

IIT agrees

with this and replaces my vague phrase “certain complex ways” by a precise definition: the information processing needs to be integrated, that is, Φ needs to be large. Giulio’s argument for this is as powerful as it is simple: the conscious system needs to be integrated into a unified whole, because if it instead consisted of two independent parts, then they’d feel like two separate conscious entities rather than one. In other words, if a conscious part of a brain or computer can’t communicate with the rest, then the rest can’t be part of its subjective experience.

we saw how a neural network, for example, is a powerful substrate for learning because, simply by obeying the laws of physics, it can rearrange itself to get better and better at implementing desired computations.

But how can consciousness feel so non-physical if it’s in fact a physical phenomenon? How can it feel so independent of its physical substrate? I think it’s because it is rather independent of its physical substrate, the stuff in which it is a pattern!

We encountered many beautiful examples of substrate-independent patterns in chapter 2,

including waves, memories and c...

We saw how they weren’t merely more than their parts (emergent), but rather independent of their parts, ...

For example, we saw how a future simulated mind or computer-game character would have no way of knowing whether it ran on Windows, Mac OS, an Android phone or some other operating system, because it would be substrate-independent. Nor could it tell whether the logic gates of its computer were made of transistors, optical circuits or other hardware. Or what the fundamental laws o...

In summary, I think that consciousness is a physical phenomenon that feels non-physical because it’s like waves and computations: it has properties independent of its specific physical substrate. This follo...

This le...

a radical idea that I really like: If consciousness is the way that information feels when it’s processed in certain ways, then it must be substrate-independent; it’s only the structure of the information processing that matters, not the structure of the matter doing the information pr...

As we’ve seen, physics describes patterns in spacetime that correspond to particles moving around. If the particle arrangements obey certain principles, they give rise to emergent phenomena that are pretty independent of the particle substrate, and have a totally different feel to them. A great example of this is information processing, in computronium. But we’ve now taken this idea to another level: If the information processing its...

This places your conscious experience not one but two levels ...

No w...

your mind feels non-...

This raises a question: What are these principles that information processing needs to obey to be conscious? I don’t pretend to know what conditions are sufficient to guarantee consciousness, but here are four necessary conditions that I’d bet on and have explored in my research: Principle Definition Information principle A conscious system has substantial information-storage capacity. Dynamics principle A conscious system has substantial information-processing capacity. Independence principle A consciou...

independent...