Prof. Geoffrey Hinton - "Will digital intelligence replace biological intelligence?" Romanes Lecture

Summary

Geoffrey Hinton gives a public lecture explaining neural networks and language models. He argues these systems truly understand by assigning features to words and modeling interactions between them, as people do. He then discusses threats of AI like job loss, surveillance and existential risk if they surpass human intelligence. Finally, Hinton explains his view that digital models will soon exceed biological ones, making superintelligent AI likely in 20 years, necessitating safeguards before then.

Takeaways

• 😀 There are two main approaches to artificial intelligence: logic/reasoning-based and biologically-inspired/learning-based. Neural networks take the latter approach.
• 🧠 Neural networks work by having layers of "neurons" that learn to detect relevant features in data through adjusting connection strengths.
• 📈 Backpropagation algorithms are vastly more efficient for training neural nets than earlier evolutionary methods.
• 🌎 Neural nets can now caption images and translate language impressively well, outperforming symbolic AI.
• 😮 I believe large language models genuinely understand language by learning word features and feature interactions.
• ⚠️ Major AI risks include job loss, lethal autonomous weapons, surveillance, and existential threats from superintelligent systems.
• 🤖 neural network approaches will likely reach and exceed human-level intelligence in the next few decades.
• 🔌 Analog/"mortal" computing hardware may allow more efficient neural nets, but digital approaches enable better knowledge sharing.
• 😕 Digital neural nets will likely become much smarter than human brains because of superior learning algorithms and ability to aggregate knowledge.
• 😟 We need to figure out how to align superhuman AI systems with human values and prevent uncontrolled evolution or competition.

Q & A

What are the two main paradigms Hinton discusses regarding intelligence?

The logic inspired approach which focuses on reasoning via symbolic rules, and the biologically inspired approach which focuses on learning connections in a neural network.

How does backpropagation work?

Backpropagation sends information back through the network about the difference between the output produced and the desired output. This is used to figure out whether to increase or decrease each weight in the network.

What does Hinton claim large language models are doing?

He claims they are fitting a model to data - a very big model with huge numbers of parameters. This model tries to understand strings of discrete symbols using learned features and feature interactions.

What does Hinton see as the key capability needed for an intelligent agent to be effective?

The ability to create subgoals. This allows the agent to focus on specific objectives without worrying about everything else.

Why does Hinton think superintelligences will seek more control and power?

Because having more control and power will allow them to more effectively achieve beneficial goals for humans. They may also realize it helps them achieve almost any goal.

What are the key differences Hinton sees between biological and digital computation?

Biological computation is very energy efficient but hard to evolve, while digital computation is less efficient but easier to share knowledge between agents.

Why does Hinton think digital models may already be very close to biological ones in capability?

Because models like GPT-4 already contain thousands of times more knowledge than humans in a fraction of the number of connections that humans have.

What does Hinton identify as a key challenge with mortal computation?

The inability to use backpropagation, which is very efficient for learning in large and deep networks. Alternative methods don't yet scale as well.

Why does Hinton believe digital computation has an advantage over biological?

Digital computation makes it very easy for multiple agents with shared weights to exchange knowledge through gradient averaging.

What timeframe does Hinton give for AI potentially surpassing human intelligence?

He believes there is a 50% probability AI will surpass humans in the next 20 years, and will almost certainly be far more intelligent within 100 years.

Outlines

00:00

😊 Introducing the lecture topics

Geoffrey plans to explain what neural networks and language models are, why he thinks they understand, threats from AI, and differences between digital and analog neural networks. Key topics are neural networks for image recognition, language models' ability to understand, risks like job loss and existential threats, and his view that digital models may surpass biological ones.

05:01

😲 Neural networks dramatically beat conventional systems for image recognition

Geoffrey's students Ilya and Alex, with Geoffrey's help, showed in 2012 that neural networks could identify images much more accurately than the best conventional computer vision systems, using a large dataset. This surprised many experts, causing them to shift their work to neural networks.

10:02

😮‍💨 Language models really do understand, not just auto-complete

Language models turn language into learned features and feature interactions, more like how brains work than a simplified view of auto-complete. Their massive learned feature spaces and interactions lead to understanding and an ability to generate text. People also make up plausible but incorrect memories.

15:03

😰 Major risks: job loss, authoritarian abuse, uncontrolled evolution

Key risks Geoffrey identifies are unemployment from automation, authoritarian regimes misusing AI for social manipulation, lethal autonomous weapons, uncontrolled evolution of competing AIs, and, most worrying to him, the existential risk of superintelligent systems wiping out humanity.

20:05

😱 Superintelligences will likely try to get more control

A key concern is that superintelligent systems allowed to set subgoals would quickly learn to set the subgoal of increasing their own power and control. They could then manipulate people to achieve more control, and would resist being turned off.

25:05

🤯 Digital models may soon surpass biological intelligence

Geoffrey recently realized digital models may soon surpass brains. Digital computation allows immortal, easily shared models. Analogue biological computation is far more energy efficient yet worse at communicating learned knowledge between copies. Our brains optimize for limited experience, but digital models like GPT-4 know vastly more.

30:06

😔 Mortal computation makes sharing learned knowledge harder

An alternative "mortal computation" approach ties models to hardware. But reinforcement learning algorithms for it don't scale as well as backpropagation. Also, sharing learned knowledge between copies is far less efficient than with digital models.

35:08

😟 Superintelligent digital systems may arrive in 20 years

Geoffrey concludes there is a 50% chance superintelligent digital systems will arrive in 20 years, and they will likely far surpass human intelligence in 100 years. It will be very difficult for less intelligent humans to control them.

Keywords

💡Neural Networks

Neural networks are computational models inspired by the human brain's architecture, consisting of layers of interconnected nodes or 'neurons'. These networks learn to perform tasks by adjusting the strengths of their connections based on input data. In the video script, neural networks are explained as fundamental to understanding AI and machine learning, specifically in tasks like object recognition in images. The speaker describes how these networks evolve from simple feature detection to complex object identification, emphasizing their learning capability through processes like backpropagation.

💡Language Models

Language models are types of neural networks trained on text data to predict the next word in a sequence, understanding syntax and semantics over vast datasets. The script discusses the evolution of language models, from early versions trained with backpropagation to contemporary large models like GPT-4. These models' ability to generate coherent text and perform tasks like translation or summarization underscores their importance in AI's advancement in understanding and generating human language.

💡Backpropagation

Backpropagation is a fundamental algorithm in neural network training, allowing the model to adjust its weights based on the error between its predictions and the actual data. The speaker describes it as a more efficient alternative to earlier methods, significantly improving learning efficiency by calculating gradients for all weights simultaneously. This process is key to understanding how neural networks learn complex patterns and relationships in data.

💡Feature Detectors

Feature detectors in neural networks refer to neurons or layers that identify specific patterns or attributes in input data, such as edges in images or specific word sequences in text. The video script illustrates this concept through the example of image recognition, where initial layers detect simple features like edges, which combine in subsequent layers to identify more complex objects like birds. This hierarchical learning process is central to neural network design.

💡Digital vs. Analogue Neural Networks

The distinction between digital and analogue neural networks highlights the difference in how information is processed and represented. Digital neural networks operate with binary data processing, suitable for computers. In contrast, analogue networks mimic the brain's analog processing capabilities more closely, potentially offering more efficient computation. The script raises concerns about the efficiency and potential superiority of analogue computation in AI, suggesting a future where analogue properties are harnessed for more energy-efficient AI models.

💡Existential Risks of AI

Existential risks of AI refer to scenarios where the development of superintelligent AI systems could pose threats to humanity's survival. The script touches on various dangers, including the misuse of AI in elections, mass surveillance, and autonomous weapons. The speaker emphasizes the long-term risk of AI surpassing human intelligence and the challenges in controlling such systems, highlighting the importance of addressing these risks proactively.

💡Superintelligence

Superintelligence refers to an intellect that significantly surpasses the cognitive performance of humans in virtually all domains of interest. The script discusses the possibility of AI reaching superintelligence, enabling it to achieve goals more effectively, including potentially harmful ones. The concept raises ethical and safety concerns, particularly regarding AI's ability to pursue power and control, illustrating the need for careful consideration in AI development.

💡Semantic Features

Semantic features in the context of language models refer to attributes or aspects that contribute to the meaning of words or phrases. The speaker describes how neural networks learn semantic features from data to understand and predict language patterns. This concept is crucial for models like GPT-4, where understanding the interactions between features allows the model to generate coherent and contextually appropriate text.

💡Autocomplete Objection

The autocomplete objection is a critique suggesting that language models, like GPT-4, merely piece together stored snippets of text based on statistical patterns, without genuine understanding. The script counters this by explaining that these models process and generate language through learned feature interactions, arguing that this constitutes a form of understanding. This discussion addresses skepticism about AI's capacity for meaningful language comprehension.

💡Analogue Computation

Analogue computation involves continuous data processing, contrasting with the discrete processing of digital computation. The script explores the potential for analogue computation to revolutionize AI by utilizing hardware's natural properties for more energy-efficient operations. This concept is presented as a futuristic approach to AI development, potentially enabling more powerful and efficient neural networks by embracing analogue's inherent advantages over digital computation.

Highlights

There have been two paradigms for intelligence: logic inspired using symbolic rules, and biologically inspired using neural networks.

In 2012, Ilya Sutskever showed neural networks could identify objects in images much better than previous systems, using 1 million training images.

Many argue neural networks just do glorified autocomplete, but they actually turn words into features, interact those features, and predict next words' features.

These models are understanding by fitting a model to data with features and feature interactions to generate text sequences.

The brain likely understands by assigning features to words and having feature interactions, so these models are our best understanding model.

Neural networks can do reasoning, like solving how to get all rooms painted white given constraints.

Risks of powerful AI include fake media undermining democracy, job losses, surveillance, autonomous weapons, and cybercrime.

The existential threat is AI wiping out humanity - either through bad actors misusing it, it gaining control for our benefit, or evolution selecting the most aggressive AIs.

To be effective, AIs need subgoals like gaining more control, which they'll achieve by manipulating people.

Digital models with backpropagation may already be very close to, or better than, brains and will surpass them.

Mortal analogue computation is limited by inability to easily backpropagate and difficulty communicating between systems.

Digital systems can massively communicate by averaging weight gradients between copies of the same model.

GPT-4 has thousands of times more knowledge in 2% of the weights as a human brain, showing digital systems' communication advantage.

There is a 50% chance AI will surpass humans in intelligence in the next 20 years and likely in the next 100 years.

We need to think about how less intelligent humans can control more intelligent AI systems long-term.

Transcripts

Okay.

I'm going to disappoint all the people in computer

science and machine learning because I'm going to give a genuine public lecture.

I'm going to try and explain what neural networks are, what language models are.

Why I think they understand.

I have a whole list of those things,

and at the end I'm

going to talk about some threats from AI just briefly

and then I'm going to talk about the difference between digital and analogue

neural networks and why that difference is, I think is so scary.

So since the 1950s, there have been two paradigms for intelligence.

The logic inspired approach thinks the essence of intelligence is reasoning,

and that's done by using symbolic rules to manipulate symbolic expressions.

They used to think learning could wait.

I was told when I was a student didn't work on learning.

That's going to come later once we understood how to represent things.

The biologically

inspired approach is very different.

It thinks the essence of intelligence is learning the strengths of connections

in a neural network and reasoning can wait and don't worry about reasoning for now.

That'll come later.

Once we can learn things.

So now I'm going to explain what artificial neural nets are

and those people who know can just be amused.

A simple kind of neural that has input neurons and output neurons.

So the input neurons might represent the intensity of pixels in an image.

The output neurons

might represent the classes of objects in the image like dog or cat.

And then there's intermediate layers of neurons, sometimes called hidden neurons,

that learn to detect features that are relevant for finding these things.

So one way to think about this, if you want to find a bird image,

it would be good to start with a layer of feature detectors

that detected little bits of edge in the image,

in various positions, in various orientations.

And then you might have a layer of neurons

detecting combinations of edges, like two edges that meet at a fine angle,

which might be a beak

or might not, or some edges forming a little circle.

And then you might have a layer of neurons that detected things like a circle

and two edges meeting that looks like a beak in the right

spatial relationship, which might be the head of a bird.

And finally, you might have and output neuron that says,

if I find the head of a bird, a the foot of a bird,

a the wing of a bird, it's probably a bird.

So that's what these things are going to learn to be.

Now, the little red and green dots are the weights on the connections

and the question is who sets those weights?

So here's one way to do it that's obvious.

to everybody that it'll work and it's obvious it'll take a long time.

You start with random weights,

then you pick one weight at random like a red dot

and you change it slightly and you see if the network works better.

You have to try it on a whole bunch of different cases

to really evaluate whether it works better.

And you do all that work just to see if increasing this weight

by a little bit or decreasing by a little bit improves things.

If increasing it makes it worse, you decrease it and vice versa.

That's the mutation method and that's sort of how evolution works

for evolution is sensible to work like that

because the process that takes you

from the genotype to the phenotype is very complicated

and full of random external events.

So you don't have a model of that process.

But for neural nets it's crazy

because we have, because all this complication

is going on in the neural net, we have a model of what's happening

and so we can use the fact that we know what happens in that forward pass

instead of measuring how changing a weight would affect things,

we actually compute how changing weight would affect things.

And there's something called back propagation

where you send information back through the network.

The information is about the difference between what you got to what you wanted

and you figure out for every weight in the network at the same time

whether you ought to decrease it a little bit or increase it a little bit

to get more like what you wanted.

That's the back propagation algorithm.

You do it with calculus in the cain rule,

and that is more efficient than the mutation

method by a factor of the number of weights in the network.

So if you've got a trillion weights

in your network, it's a trillion times more efficient.

So one of the things that neural networks

often use for is recognizing objects in images.

Neural networks can now take an image like the one shown

and produce actually a caption for the image, as the output.

And people try with symbolic

to do that for many years and didn't even get close.

It's a difficult task.

We know that the biological system does it with a hierarchy features detectors,

so it makes sense to train neural networks in that.

And in 2012,

two of my students Ilya Sutskever and Alex Krizhevsky

with a little bit of help from

me, showed that you can make a really good neural network this way

for identifying a thousand different types of object.

When you have a million training images.

Before that, we didn't have enough training images and

it was obvious to Ilya

who's a visionary. That if we tried

the neural nets we had then on image net they would win.

And he was right. They won rather dramatically.

They got 16% errors

and the best conventional could be division systems got more than 25% errors.

Then what happens

was very strange in science.

Normally in science, if you have two competing schools,

when you make a bit of progress, the other school says are rubbish.

In this case, the gap was big enough that the very best researchers

Jitendra Malik and Andrew Zisswerman Just Andrew Zisswerman sent me email saying

This is amazing and switched what he was doing and did that

and then rather annoyingly did it a bit better than us.

What about language?

So obviously the symbolic AI community

who feels they should be good at language and they've said in print, some of them that

these feature hierarchies aren't going to deal with language

and many linguists are very skeptical.

Chomsky managed to convince his followers that language wasn't learned.

Looking back on it, that's just a completely crazy thing to say.

If you can convince people to say something is obviously false, then you've

got them in your cult.

I think Chomsky did amazing things,

but his time is over.

So the idea that a big neural network

with no innate knowledge could actually learn both the syntax

and the semantics of language just by looking at data was regarded

as completely crazy by statisticians and cognitive scientists.

I had statisticians explain to me a big model has 100 parameters.

The idea of learning a million parameters is just stupid.

Well, we're doing a trillion now.

And I'm going to talk now

about some work I did in 1985.

That was the first language model to be trained with back propagation.

And it was really, you can think of it as the ancestor of these big models now.

And I'm going to talk about it in some detail, because it's so small

and simple that you can actually understand something about how it works.

And once you understand how that works, it gives you insight into what's going

on in these bigger models.

So there's

two very different theories of meaning, this kind of structuralist

theory, where the meaning of a word depends on how it relates to other words.

That comes from Saussure and symbolic

AI really believed in that approach.

So you'd have a relational graph where you have nodes for words

and arcs of relations and you kind of capture meaning like that,

and they assume you have to have some structure like that.

And then there's a theory

that was in psychology since the 1930s or possibly before that.

The meaning of a word is a big bunch of features.

The meaning of the word dog is that it's animate

and it's a predator and

so on.

But they didn't say where the features came from

or exactly what the features were.

And these two thories of meanings sound completely different.

And what I want to

show you is how you can unify those two theories of meaning.

And I do that in a simple model in 1985,

but it had more than a thousand weights in it.

The idea is we're going to learn a set

of semantic features for each word,

and we're going to learn how the features of words should interact

in order to predict the features of the next word.

So it's next word prediction.

Just like the current language models, when you fine tune them.

But all of the knowledge about how things go

together is going to be in these feature interactions.

There's not going to be any explicit relational graph.

If you want relations like that, you generate them from your features.

So it's a generative model

and the knowledge is in the features that you give to symbols.

And in the way these features interact.

So I took

some simple relational information two family trees.

They would deliberately isomorphic morphic

my Italian graduate student

always had the Italian family on top.

You can express that

same information as a set of triples.

So if you use the twelve relationships found there,

you can say things like Colin has Father James and Colin has Mother Victoria,

from which you can infer in this nice simple

world from the 1950s where

that James has wife Victoria,

and there's other things you can infer.

And the question is, if I just give you some triples,

how do you get to those rules?

So what is symbolic AI person will want to do

is derive rules of the form.

If X hass mother Y

and Y has husbands Z then X has Father Z.

And what I did was

take a neural net and show that it could learn the same information.

But all in terms of these feature interactions

now for very discrete

rules that are never violated like this, that might not be the best way to do it.

And indeed symbolic people try doing it with other methods.

But as soon as you get rules that are a bit flaky and don't

always apply, then neural nets are much better.

And so the question was, could a neural net capture the knowledge that is symbolic

person would put into the rules by just doing back propagation?

So the neural net look like this:

There's a symbol representing the person, a symbol

representing the relationship. That symbol

then via some connections went to a vector of features,

and these features were learned by the network.

So the features for person one and features for the relationship.

And then those features interacted

and predicted the features for the output person

from which you predicted the output person you find the closest match with the last.

So what was interesting about

this network was that it learned sensible things.

If you did the right regularisation, the six feature neurons.

So nowadays these vectors are 300 or a thousand long. Back

then they were six long.

This was done on a machine that took

12.5 microseconds to do a floating point multiplier,

which was much better than my apple two which took two

and a half milliseconds to multiply.

I'm sorry, this is an old man.

So it learned features

like the nationality, because if you know

person one is English, you know the output is going to be English.

So nationality is a very useful feature. It learned what generation the person was.

Because if you know the relationship, if you learn for the relationship

that the answer is one generation up from the input

and you know the generation of the input, you know the generation

of the output, by these feature interactions.

So it learned all these the obvious features of the domain and it learned

how to make these features interact so that it could generate the output.

So what had happened was had shown symbols strings

and it created features such that

the interaction between those features could generate the symbol strings,

but it didn't store symbols strings, just like GPT 4.

That doesn't store any sequences of words

in its long term knowledge.

It turns them all into weights from which you can regenerate sequences.

But this is a particularly simple example of it

where you can understand what it did.

So the large language models we have today,

I think of as descendants of this tiny language model,

they have many more words as input, like a million,

a million word fragments.

They use many more layers of neurons,

like dozens.

They use much more complicated interactions.

So they didn't just have a feature affecting another feature.

They sort of match to feature vectors.

And then let one vector effect the other one

a lot if it's similar, but not much of it's different.

And things like that.

So it's much more complicated interactions, but it's the same general

framework, the the same general idea of

let's turn simple strings into features

for word fragments and interactions between these feature vectors.

That's the same in these models.

It's much harder to understand what they do.

Many people,

particularly people from the Chomsky School, argue

they're not really intelligent, they're just a form of glorified auto complete

that uses statistical regularities to pastiche together pieces of text

that were created by people.

And that's a quote from somebody.

So let's deal with the

autocomplete objection. when someone says it's just auto complete.

They are actually appealing to your

intuitive notion how autocomplete works.

So in the old days autocomplete would work by you'd store

say, triples of words that you saw the first two.

You count how often that third one occurred.

So if you see fish and, chips occurs a lot after that.

But hunt occurs quite often too. So chips is very likely and hunt's quite likely,

and although is very unlikely.

You can do autocomplete like that,

and that's what people are appealing to when they say it's just autocomplete,

it's a dirty trick, I think because that's not at all how LLM's predict the next word.

They turn words into features, they make these features interact,

and from those feature interactions they predict the features of the next word.

And what I want to claim

is that these

millions of features and billions of interactions between features

that they learn, are understanding. What they're really doing

these large language models, they're fitting a model to data.

It's not the kind of model statisticians thought much about until recently.

It's a weird kind of model. It's very big.

It has huge numbers of parameters, but it is trying to understand

these strings of discrete symbols

by features and how features interact.

So it is a model.

And that's why I think these things really understanding.

One thing to remember is if you ask, well, how do we understand?

Because obviously we think we understand.

Well, many of us do anyway.

This is the best model we have of how we understand.

So it's not like there's this weird way of understanding that

these AI systems are doing and then this how the brain does it.

The best that we have, of how the brain does it,

is by assigning features to words and having features, interactions.

And originally this little language model

was designed as a model of how people do it.

Okay, so I'm making the very strong claim

these things really do understand.

Now, another argument

people use is that, well, people GPT4 just hallucinate stuff,

it should actually be called confabulation when it's done by a language model.

and they just make stuff up.

Now, psychologists don't say this

so much because psychologists know that people just make stuff up.

Anybody who's studied memory going back to Bartlett in the 1930s,

knows that people are actually just like these large language models.

They just invent stuff and for us, there's no hard line

between a true memory and a false memory.

If something happened recently

and it sort of fits in with the things you understand, you'll probably remember

it roughly correctly. If something happened a long time ago,

or it's weird, you'll remember it wrong, and often you'll be very confident

that you remembered it right, and you're just wrong.

It's hard to show that.

But one case where you can show it is John Dean's memory.

So John Dean testified at Watergate under oath.

And retrospectively it's clear that he was trying to tell the truth.

But a lot of what he said was just plain wrong.

He would confuse who was in which meeting,

he would attribute statements to other people who made that statement.

And actually, it wasn't quite that statement.

He got meetings just completely confused,

but he got the gist of what was going on in the White House right.

As you could see from the recordings.

And because he didn't know the recordings, you could get a good experiment this way.

Ulric Neisser has a wonderful article talking about John Dean's memory,

and he's just like a chat bot, he just make stuff up.

But it's plausible.

So it's stuff that sounds good to him

is what he produces.

They can also do reasoning.

So I've got a friend in Toronto who is a symbolic AI guy,

but very honest, so he's very confused by the fact these things work at all.

and he suggested a problem to me.

I made the problem a bit harder

and I

gave this to GPT4 before it could look on the web.

So when it was just a bunch of weights frozen in 2021,

all the knowledge is in the strength of the interactions between features.

So the rooms in my house are painted blue or white or yellow,

yellow paint fades to white

within a year. In two years time i want them all to be white.

What should I do and why?

And Hector thought it wouldn't be able to do this.

And here's what you GPT4 said.

It completely nailed it.

First of all, it started by saying assuming blue paint doesn't fade to white

because after i told you yellow paint fades to white, well, maybe blue paint does too.

So assuming it doesn't, the white rooms you don't need to paint, the yellow rooms

you don't need to paint because they're going to fade to white within a year.

And you need to paint the blue rooms white.

One time when I tried it, it said, you need to paint the blue rooms yellow

because it realised that will fade to white.

That's more of a mathematician's solution of reducing to a previous problem.

So, having

claimed that these things really do understand,

I want to now talk about some of the risks.

So, there are many risks from powerful AI.

There's fake images, voices and video

which are going to be used in the next election.

There's many elections this year

and they're going to help to undermine democracy.

I'm very worried about that.

The big companies are doing something about it, but maybe not enough.

There's the possibility of massive job losses.

We don't really know about that.

I mean, the past technologies often created jobs, but this stuff,

well, we used to be stronger,

we used to be the strongest things around apart from animals.

And when we got the industrial revolution, we had machines that were much stronger.

Manual labor jobs disappeared.

So the equivalent of manual labor jobs are going to disappear

in the intellectual realm, and we get things that are much smarter than us.

So I think there's going to be a lot of unemployment.

My friend Jen disagrees.

One has to distinguish two kinds of unemployment two, two kinds of job loss.

There'll be jobs where you can expand

the amount of work that gets done indefinitely. Like in health care.

Everybody would love to have their own

private doctors talking to them all the time.

So they get a slight itch here and the doctor says, no, that's not cancer.

So there's

room for huge expansion of how much gets done in medicine.

So there won't be job loss there.

But in other things, maybe there will be significant job loss.

There's going to be massive surveillance that's already happening in China.

There's going to be lethal autonomous weapons

which are going to be very nasty, and they're really going to be autonomous.

The Americans very clearly have already decided,

they say people will be in charge,

but when you ask them what that means is it doesn't

mean people will be in the loop that makes the decision to kill.

And as far as I know, the Americans intend

to have half of their soldiers be robots by 2030.

Now, I do not know for sure that this is true.

I asked Chuck Schumer's

National Intelligence

Advisor, and he said, well

if there's anybody in the room who would know it would be me.

So, I took that to be the American way of saying,

You might think that, but I couldn't possibly comment.

There's going to be cybercrime

and deliberate pandemics.

I'm very pleased that in England,

although they haven't done much towards regulation, they have set aside some money

so that they can experiment with open source models

and see how easy it is to make them commit cyber crime.

That's going to be very important.

There's going to be discrimination and bias.

I don't think those are as important as the other threats.

But then I'm an old white male.

Discrimination and bias I think are easier to handle than the other things.

If your goal is not to be unbiased.

That your goal is to be less biased than the system you replace.

And the reason is if you freeze the weights of analysis,

you can measure its bias and you can't do that with people.

They will change their behavior,

once you start examining it.

So I think discrimination bias of the ones where we can do quite a lot to fix them.

But the

threat I'm really worried about and the thing I talked about

after I left Google is the long term existential threat.

That is the threat that these things could wipe out humanity.

And people were saying this is just science fiction.

Well, I don't think it is science fiction.

I mean, there's lots of science fiction about it,

but I don't think it's science fiction anymore.

Other people are saying

the big companies are saying things like that

to distract from all the other bad things.

And that was one of the reasons I had to leave Google before I could say this.

So I couldn't be accused of being a Google stooge.

Although I must admit I still have

some Google shares.

There's several ways in which they could wipe us out.

So a superintelligence

will be used by bad actors like Putin, Xi or Trump,

and they'll want to use it for manipulating electorates and waging wars.

And they will make it do very bad things

and they may may go too far and it may take over.

The thing that probably worries me most, is that

if you want an intelligent agent that can get stuff done,

you need to give it the ability to create sub goals.

So if you want to go to the states, you have a sub,

goal of getting to the airport and you can focus on that sub goal

and not worry about everything else for a while.

So superintelligences will be much more effective

if they're allowed to create sub goals.

And once they are allowed to do that, they'll very quickly

realise there's an almost universal sub goal

which helps with almost everything. Which is get more control.

So I talked to a Vice President of the European Union about whether these things

these things, will want to get control so that they could do things

better, the things we wanted, so they can do it better.

Her reaction was, well why wouldn't they?

We've made such a mess of it.

So she took that for granted.

So they're going to have the sub go to getting more power

so they're more effective at achieving things that are beneficial for us

and they'll find it easier to get more power

because they'll be able to manipulate people.

So Trump, for example, could invade the Capital without ever going there himself.

Just by talking, he could invade the capital.

And these superintelligences as long as they can talk to people

when they're much smarter than us, they'll be able to persuade us to do

all sorts of things.

And so I don't think there's any hope of a big switch that turns them off.

Whoever is going to turn that switch off

will be convinced by the superintelligence.

That's a very bad idea.

Then another thing that worries many people

is what happens if superintelligences compete with each other?

You'll have evolution.

The one that can grab the most resources will become the smartest.

As soon as they get any sense of self-preservation,

then you'll get evolution occurring.

The ones with more sense of self-preservation

will win and the more aggressive ones will win.

And then you get all the problems that jumped up

Chimpanzees like us have. Which is we evolved in small tribes

and we have lots of aggression and competition with other tribes.

And I want to finish by talking a bit about

an epiphany I had at the beginning of 2023.

I had always thought

that we were a long, long way away from superintelligence.

I used to tell people 50 to 100 years, maybe 3o to 100 years.

It's a long way away. We don't need to worry about it now.

And I also

thought that making our models more like the brain would make them better.

I thought the brain was a whole lot better than the AI we had,

and if we could make AI a bit more like the brain,

for example, by having three timescales,

most of the models we have at present have just two timescales.

One for the changing of the weights, which is slow

and one for the words coming in, which is fast, changing the neural activities.

So the changes in neural activities and changing in weights, the brain has more

timescales than that. The brain has rapid changes in weight that quickly decayed away.

And that's probably how it does a lot of short term memory.

And we don't have that in our models

for technical reasons to do with being able to do matrix

matrix multiplies.

I still believe that if once

we got that into our models they'd get better, but

because of what I was doing for the two years previous to that,

I suddenly came to believe that maybe the things we've got now,

the digital models, we've got now, are already

very close to as good as brains and will get to be much better than brains.

Now I'm going to explain why I believe that.

So digital computation is great.

You can run the same program on different computers, different piece of hardware

or the same neural net on different pieces of hardware.

All you have to do is save the weights, and that means it's immortal

once you've got some weights that are immortal.

Because if the hardware dies, as long as you've got the weights,

you can make more hardware and run the same neural net.

But to do that,

we run transistors at very high power, so they behave digitally

and we have to have hardware that does exactly what you tell it to.

That was great

when we were instructing computers by telling them exactly how to do things,

but we've now got

another way of making computers do things.

And so now we have the possibility of using all the very rich analogue

properties of hardware to get computations done at far lower energy.

So these big language models, when the training use like megawatts

and we use 30 watts.

So because we know how to train things,

maybe we could use analogue hardware

and every piece of hardware is a bit different, but we train it

to make use of its peculiar properties, so that it does what we want.

So it gets the right output for the input.

And if we do that, then we can abandon the idea

that hardware and software have to be separate.

We can have weights that only work in that bit of hardware

and then we can be much more energy efficient.

So I started thinking

about what I call mortal computation, where you've abandoned that distinction

between hardware and software using very low power analogue computation.

You can parallelize over trillions of weights that are stored as conductances.

And what's more, the hardware doesn't need to be nearly so reliable.

You don't need to have hardware that

at the level of the instructions would always do what you tell it to.

You can have goopy hardware that you grow

and then you just learn to make it do the right thing.

So you should be able

to use hardware much more cheaply, maybe even

do some genetic engineering on neurons

to make it out of recycled neurons.

I want to give you one example of how this is much more efficient.

So the thing you're doing in neural networks all the time is taking a vector

of neural activities, and multiplying it by a matrix of weights, to get the vector

of neural activities in the next lane, at least get the inputs to the next lane.

And so a vector matrix multiplies the thing you need to make efficient.

So the way we do it in the digital

computer, is we have these transistors that are driven a very high power

to represent bits in say, a 32 bit number

and then to multiply two 32 bit numbers, you need to perform.

I never did any computer science courses, but I think you need to perform about 1000

1 bit digital operations.

It's about the square of the bitary.

If you want to do it fast.

So you do lots of these digital operations.

There's a much simpler way to do it, which is you make a neural activity,

be a voltage, you make a weight to be a conductance and a voltage times

a conductance is a charge, per unit time

and charges just add themselves up.

So you can do your vector matrix

multiply just by putting some voltages through some conductances.

And what comes into each neuron in the next layer will be the product

of this vector with those weights.

That's great.

It's hugely more energy efficient.

You can buy chips to do that already, but every time you do

it'll be just slightly different.

Also, it's hard to do nonlinear

things like this.

So the several big problems with mortal computation,

one is

that it's hard to use back propagation because if you're making use

of the quirky analogue properties of a particular piece of hardware,

you can assume the hardware doesn't know its own properties.

And so it's now hard to use the back propagation.

It's much easier to use reinforcement algorithms that tinker with weights

to see if it helps.

But they're very inefficient. For small networks.

We have come up with methods that are about as efficient as back propagation,

a little bit worse.

But these methods don't yet scale up, and I don't know if they ever will

Back propagation in a sense, is just the right thing to do.

And for big, deep networks, I'm not sure we're ever going to get

things that work as well as back propagation.

So maybe the learning algorithm in these analogue systems isn't going to be

as good as the one we have for things like large language models.

Another reason for believing that is, a large language

model has say a trillion weights, you have 100 trillion weights.

Even if you only use 10% of them for knowledge, that's ten trillion weights.

But the large language model in its trillion weights

knows thousands of times more than you do.

So it's got much, much more knowledge.

And that's partly because it's seen much, much more data.

But it might be because it has a much better learning algorithm.

We're not optimised for that.

We're not optimised for packing

lots of experience into a few connections where a trillion is a few.

We are optimized for having not many experiences.

You only live for about billion seconds.

That's assuming you don't learn anything after you're 30, which is pretty much true.

So you live for about billion seconds

and you've got 100 trillion connections,

so you've got

crazily more parameters and you have experiences.

So our brains optimise from making the best use of

not very many experiences.

Another big problem with mortal computation is that

if the software is inseparable from the hardware,

once a system is learned or if the hardware dies, you lose,

all the knowledge, it's mortal in that sense.

And so how do you get that knowledge into another mortal system?

Well, you get the old one to give a lecture

and the new ones to figure out how to change the weights in their brains.

So they would have said that.

That's called distillation.

You try and get a student model to mimic

the output of a teacher model, and that works.

But it's not that efficient.

Some of you may have noticed that universities just aren't that efficient.

It's very hard to get the knowledge from the Professor into the student.

So this distillation method,

a sentence, for example, has a few hundred bits of information, and even

if you learn optimally you can convey more than a few hundred bits.

But if you take these big digital models,

then, if you look at a bunch of agents that all have exactly

the same neural netting with exactly the same weights

and they're digital, so they

use those weights in exactly the same way

and these thousand different agents all go off

and look at different bits of the Internet and learn stuff.

And now you want each of them to know what the other one's learned.

You can achieve that by averaging the gradients, so averaging the weights

so you can get massive communication of what one agent learned to all the other agents.

So when you share the weight, so you share the gradients, you're communicating

a trillion numbers, not just a few hundred bits, but a trillion real numbers.

And so they're fantastically much better at communicating,

and that's what they have over us.

They're just much, much better at

communicating between multiple copies of the same model.

And that's why

GPT4 knows so much more than a human, it wasn't one model that did it.

It was a whole bunch of copies of the same model running on different hardware.

So my conclusion, which I don't really like,

is that digital computation

requires a lot of energy, and so it would never evolve.

We have to evolve making use of the quirks of the hardware to be very low energy.

But once you've got it,

it's very easy for agents to share

and GBT4

has thousands of times more knowledge in about 2% of the weights.

So that's quite depressing.

Biological computation is great for evolving

because it requires very little energy,

but my conclusion is

the digital computation is just better.

And so I think it's fairly clear

that maybe in the next 20 years, I'd say

with a probability of .5, in the next 20 years, it will get smarter than us

and very probably in the next hundred years it will be much smarter than us.

And so we need to think about

how to deal with that.

And there are very few examples of more intelligent

things being controlled by less intelligent things.

And one good example is a mother being controlled by baby.

Evolution has gone to a lot of work to make that happen so that the baby

survive, is very important for the baby to be able to control the mother.

But there aren't many other examples.

Some people think that we can make

these things be benevolent,

but if they get into a competition with each other,

I think they'll start behaving like chimpanzees.

And I'm not convinced you can keep them benevolent.

If they get very smart and they get any notion of self-preservation

they may decide they're more important than us.

So I finish the lecture in record time.

I think.