I'm Steve Strogatz, and this is The Joy of Why, a podcast from Quantum Magazine that takes you into some of the biggest unanswered questions in math and science today.

In this episode, we're going to ask, is there more to math than the equal sign?

In other words, can we use the logical power of math

to talk about what it means to be essentially the same

without having to be exactly and strictly equal?

Which brings us to category theory.

It's often described as the mathematics of mathematics,

a kind of bird's-eye view of the entire subject.

But what does that mean?

If mathematics relies on abstractions, then proponents of category theory say it provides

a sound scaffolding for those abstractions, a way to make connections and recognize patterns

and relationships across a broad range of topics and scales, such as the various

shapes of space or different types of symmetry. But some mathematicians, especially some grouchy

old-timers, question what category theory is really telling us about math that is new? What's the

point of it? Even some of its most ardent practitioners have

affectionately described it as abstract nonsense. Lately, though, category theory is all the rage. It's not

just hot in the world of math, it's now being used in computer science, physics, engineering, chemistry,

linguistics, and more. Though it began as an abstract branch of pure math,

it's turning out to be a whole new way of thinking about lots of things,

including situations in everyday life.

Our guest today, Dr. Eugenia Chang, will help us understand category theory better.

She's a scientist in residence at the School

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