James Fodor

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3,084 appearances 4 recordings 1 series first heard Jun 2026 last heard 30 Aug

James Fodor’s voice in public audio — every appearance, attributed to the second.

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Recordings per month over the last 12 months — 4 in all, peaking in Aug 2026 with 2.

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The Science of Everything Podcast · Episode 164: Gauge Theory and the Higgs Boson · 30 Aug 2026 podcast

So if you have five rocks and you take away three, you have two rocks left over.

Interestingly, when we

you think about taking things away, that introduces this notion of subtraction, which when you apply it to then having taking a bigger number away from a smaller number, it leads to this notion of negative numbers.

Negative numbers are very useful because they can be used to describe, for example, someone who owes money.

If they have a negative amount of money, that kind of means they owe someone else money.

They can also be used in a wide range of other applications.

But if you're trying to ask, like, what is what does it mean to have a negative rock?

Well, I mean, it doesn't really mean anything in that sense.

It's sort of like, it's not exactly the same, but it's sort of like an extra degree of freedom.

And that what we've introduced with the mathematics goes beyond

and what we can directly apply in a physical sense.

You can't literally have a negative number of things.

A negative number is more like exists conceptually as like the difference between a bigger number and a smaller number, but it can't be directly instantiated physically.

So that's just an example, uh, that's not a gauge theory or anything, but it's just an example of how often the mathematics used to describe things in the physical world can lead to us describing things that don't have a direct physical correlate.

And in the case of a gauge theory, that amounts to having extra degrees of freedom that don't correspond to anything physical.

That's fine to have that in the theory, but what it does is it introduces extra extra parameters that we need to introduce to get the theory to work, but don't actually make any difference physically.

So I've talked previously about the Lagrangian.

That's uh a way to describe the energy of a system, and it's what we use in quantum field theory to describe particles and their interactions.

In gauge theories, Lagrangians have internal degrees of freedom, which exist in the mathematics, but don't correspond to anything physical.

So when we actually use the theory to compute something that's experimentally observable, we have to

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