Generative AI hallucinates, creating a truth problem that science can't afford. Computer scientist Tudor Achim thinks a 400-year-old idea holds the fix: Leibniz's dream of a logical framework where errors are simply impossible. Learn about his idea for mathematical superintelligence that would ground AI in formal verification, turning unreliable chatbots into rigorous partners for scientific discovery. (Recorded at TEDAI San Francisco 2025 on October 21, 2025)
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Mathematics has served as the invisible engine of human progress for millennia, providing the foundation for all modern technology. However, the traditional human-led process of peer review is becoming a bottleneck as AI accelerates the production of complex proofs. To overcome this, the speaker proposes transitioning to formal mathematics to ensure absolute verification.
Let's take a look at this clay tablet.
It might not look like much,
but it's actually some of the oldest mathematics we have.
It's a 4,000-year-old message in a bottle
from ancient Babylon,
a precursor to the quadratic equation.
And for four millennia,
people have been doing math basically the same way.
Someone will have a brilliant idea,
they'll write it down,
and their peers will discuss and check it.
It's a process built on creativity,
communication, and most importantly,
trust between people.
And what might seem like a humble or simple process
is anything but.
It's not just been successful,
it's been, as the physicist Eugene Wigner famously put it,
unreasonably effective.
Wigner was pondering and trying to unravel a deep mystery.
Why should the abstract, creative,
and often bizarre ideas
that spring from a mathematician's imagination
so often be the perfect language
with which we understand the universe?
Why should the strange laws of non-Euclidean geometry,
which were originally conceived of
as a thought experiment in the 19th century,
turn out to be the exact mathematics
that Einstein needed for general relativity?
Why should the esoteric math of group theory,
which was originally designed
to study the abstract nature of symmetry,
be fundamental to understanding everything
from particle physics to the patterns in crystals?
Well, there's no logical reason it has to be this way.
This strange connection between pure mathematical thought
and the real world has actually been
the invisible engine driving human progress.
Every piece of technology that defines our lives
was ignited with a mathematical spark.
If you take the device in your phone,
its brain is based on the quantum mechanics
of semiconductors, and that's a theory built
on linear algebra and complex numbers.
The wireless signals that get data to it,
they're just a concrete manifestation
of Maxwell's equations.
And finally, the security that protects your data online
is based on number theory,
which for a long time was truly considered
the most pure and least applicable
possible branch of mathematics.
And now, it safeguards trillions of dollars
in the global economy.
And now we come to AI.
Modern AI is not just built with math,
it's forged from it.
A neural network is just a monumental structure
of applied mathematics, and when AIs learn,
they're using the tools of calculus
to navigate vast landscapes of possibilities
with billions of dimensions.
So AI is, in its soul, a mathematical idea
that's given life through computation.
So we agree that math is the foundation
that modern civilization's based on,
but that foundation is starting
to show some signs of strain.
The very process of human-led discovery
that's gotten us to this point
is nearing a breaking point,
buckling under the weight of its own success.
And now AI, which is one of mathematics' greatest creations,
is accelerating us towards that breaking point
faster than the world's ready for.
So let's just look at some evidence.
Consider the Poincaré conjecture.
This is a legendary problem.
It's a fundamental question about the nature
of three-dimensional shapes originally posed in 1904.
And for nearly a century,
it stood as an unconquered Everest of mathematics.
Until in 2002, a Russian mathematician
working in isolation named Grigori Perelman
posted a series of three short cryptic papers online.
He didn't bother submitting them to a journal,
he just put them on the internet and walked away.
His fellow mathematicians had to stop what they were doing
and try to decipher it.
And several teams working independently
of the best apologists in the world
took the next four years to try to unpack the arguments,
fill in the logical gaps,
and eventually at the end, after they really reviewed it,
declared that yes, he did it.
He proved the Poincaré conjecture.
But that's interesting,
because it took one person to write a proof
and a global multi-year intellectual mobilization
to check it.
And that's in the best case, when the proof is correct.
Consider Andrew Wiles' proof of Fermat's Last Theorem.
With the electrifying announcement in 1993 in Cambridge,
the world celebrated.
But during the peer review process deep in it,
a single thread was found out of place
in that magnificent tapestry of a proof,
and when we started to pull on it,
the proof started to unravel.
And this wasn't a small mistake.
Andrew Wiles and his collaborator, Richard Taylor,
took two years of heroic secret effort to try to fix it.
And that effort included some insights
that Andrew Wiles said
were among the most important in his life.
And that's before we throw AI into the mix.
Two short years ago,
AI could barely solve
entry-level high school math contest problems.
They were very clever, but brittle.
Now, in 2025, they can compete with the best of us
at the International Math Olympiad,
which is the premier pre-college math competition.
But the interesting bit is the following.
The AI might work for four hours
and produce a purported solution,
which takes an expert human mathematician
maybe up to an hour to check.
And we all know the exponential trend that AI is on.
So we can expect it's not gonna be
one proof in an afternoon.
It's gonna be 1,000 pretty soon.
And they're not gonna be attempts
to solve math contest problems.
They're gonna be attacks on the most fundamental
and important questions of the day,
whether it's the Riemann hypothesis, Navier-Stokes,
or P versus NP, just to pick a few.
We simply don't have the human bandwidth
to review all these proofs.
There's only a couple thousand mathematicians
that are qualified to do it,
and they already have day jobs.
And it's not just a verification bottleneck.
The very process by which we train these AIs
is taking the data off the internet, which is from humans,
post-training them with human feedback.
And so we're essentially baking in the cognitive biases
and the flawed reasoning of humans
into these future engines of discovery.
So the conclusion is in some sense obvious.
Humans are becoming the bottleneck of verification for AI.
Another question is, where does that leave us?
Is this the end of the road
for reliable mathematical discovery?
Are we resigned to drown in a sea of unverified claims
where we can't really tell truth from fiction?
And are we about to squander the opportunity
for AI to revolutionize math?
Well, the good news is no,
but it does mean it's time to upgrade
the 4,000-year-old operating system of math
and move away from the imprecise
and ambiguous nature of human language
and towards a language that computers can understand.
The solution is formal mathematics.
But before I tell you how this futuristic idea works,
we should first recognize
that it has a deep and fascinating history
dating back to the 17th century
where a mathematician actually laid out the roadmap
with stunning foresight.
400 years ago, in a Europe
torn by religious and political conflict,
a polymath named Gottfried Wilhelm Leibniz
had a vision of breathtaking ambition.
He was a contemporary of Newton
and a co-creator of calculus,
but his dreams went far beyond that.
He dreamed of something called a universal characteristic,
which was a system for perfectly encoding
all scientific and philosophical thought.
And the system had three parts.
First, you need a perfect logical language.
Second, you need a grand encyclopedia written on language
that contains all verified human thought.
And third, and this is the master stroke,
you need a so-called engine of reason,
a system of mechanical rules
by which you can automatically derive new facts
from that library
as surely as a calculator performs arithmetic.
Now, Leibniz thought this would revolutionize humanity.
With a system like this,
if two people had an intellectual conflict,
they would resort to logic and not rhetoric to resolve it.
They would simply sit down, say,
calculemus, let us calculate,
and get to the bottom of it.
In some sense, it was meant to be
a universal calculator for truth.
Now, Leibniz was a bit of an optimist.
He thought this would take a small group of people
five years to build,
and he was off by several centuries.
But what I think is really remarkable
is that in 2025, truly for the first time in history,
it's actually possible to realize this philosopher's dream.
So what do we need?
Well, we need a perfect logical language.
Turns out we've got it.
It's called Lean.
Lean is a programming language,
but it's also what's known as a proof assistant.
You can think of it as a programming environment
for mathematical proofs
where it doesn't just give you feedback
if you have a syntax error here or there,
it's actually looking at the core
of the mathematical argument
and telling you if you have any problems anywhere in it.
Great.
What's the second thing we need?
We need the grand encyclopedia.
Well, the good news is we've got that too.
It's called Mathlib.
Mathlib is an open-source project.
It's about two million lines of code in Lean,
and it covers a lot of the undergraduate
and graduate math curriculum.
You can think of it like a Wikipedia for proven truth
where every edit is computationally certified
for correctness.
We've got the language, we've got the encyclopedia.
What about the engine of reason?
Well, we could try to have humans do it,
but you gotta write a lot of Lean code,
and the level of robotic precision
you need to write a formal proof
is not something that human creativity is so well-suited for.
And that's how we've come full circle.
It turns out that AI is the key
to making this whole thing work.
In the future, AI is not just gonna be writing
math papers in English for humans to read.
They're gonna be writing math proofs in Lean
for computers to check.
And that is the fundamental key
that makes it possible to use Leibniz's vision
to unlock the full potential of AI and mathematics.
Because when a math AI spits out a proof in Lean
of, let's say, the Riemann hypothesis,
we're not gonna need humans to go through
every single line of the proof in painstaking detail,
check every single case,
and understand the possibly strange
and alien logic of the proof just to see if it's correct.
Instead, all we're gonna do is we're gonna take those files,
we're gonna give them to a Lean compiler,
and if it builds,
we can know with absolute certainty it's correct.
And this is what fundamentally alters
our relationship with AI.
AI can now become a true collaborator,
one whose word we don't have to take on blind faith.
We get to trade in the tedium of checking
for the creative joy of discovery.
Humans get to use our intuition and judgment.
We ask the questions, we chart the course,
we propose the brilliant conjectures,
and then we delegate to AI to explore
the vast oceans of logic to find the correct answer,
and then a computer confirms
that we've gotten to the destination.
And the amazing thing is that
this isn't just some far-off science fiction dream.
It turns out that at this year's International Math Olympiad
automated systems were able to find solutions
to five of the six problems
in a way that computers could check
and required no human review whatsoever.
And that's enough to get a gold medal level performance.
So the transition's already happening.
So, are humans gonna be the bottleneck for math research?
Well, the answer is yes,
but only if we refuse to change,
only if we insist on being the only thinkers
and the only checkers.
But if we're able to realize this 400-year-old vision,
we're not gonna replace ourselves,
we're gonna elevate ourselves.
We're gonna put ourselves in the driver's seat
as the explorers, the architects, and the question askers.
And that means that formal mathematics
is the key to this new era of discovery
based on the powerful and essential partnership
between human imagination and mathematical superintelligence.
Thank you.