Effective Field Theory (EFT)

Eric Weinstein

@EricRWeinstein

Congratulations to John Donahue on winning the Sakurai prize!

If you have heard me say that fundamental physics has been basically stagnant since 1984 or 1973, this is one of the best counter arguments against my argument…particularly if I am using shorthand or am not being careful.

Essentially this argument, continued on from ideas of Ken Wilson, is that there is no fundamental physics. Fundamental physics to this way of thinking is an illusion born of a narcissism and confusion.

That seems crazy. But it is technically, theoretically and practically correct. What it says is that everything observed happens at a scale. Your arm is a limb at the scale of anatomy, made of tissues at the scale of histology; which are in turn made of cells at the scale of cytology. Etc. There is no fundamental in arm, or skin, or basal cell. Each belongs to a scale and is pseudo-fundamental (at best) only to that scale.

So this way of emphasizing the scale while accepting non-renormalizability and the incompleteness of descriptions in most all theories at every energy level took over in many ways. And it IS solid, responsible theory. I don’t hate it. It’s not wrong. And it was the quiet revolution against string theory which partially worked because the String theorists were already sold on Wilson.

I don’t fight the Effective Field Theorists the same way. They are doing real work. Good work. Work that needs to be done.

A great choice. Mazal Tov.

5:00 PM · Nov 6, 2025

Daniel Green

@nu_phases

Reminder: Effective field theory is a revolutionary development in fundamental physics that has transformed the field over the past 40 years (that also makes many verified experimental predictions).

Congrats to John F Donoghue!

6:47 PM · Nov 5, 2025

Eric Weinstein

@EricRWeinstein

Let that stand alone.

I know that many will want to know “if you believe that, then what is your quibble?”

Ok. Here goes.

They forced us to turn away from fundamental physics and are thus ultimately defeatist. Where Daniel writes “EFT is a revolutionary development in fundamental physics” he is in a sense technically right. But I see this as spiritually wrong.

The aim of the EFT philosophy is get people to wake up and realize a horrible truth:

“THERE IS PROBABLY NO FUNDAMENTAL PHYSICS FOR US.”

That *IS* likely true. And a bitter pill if so.

*And* I totally don’t believe it. Geometric Unity (GU) is dedicated to the diametrically opposite conclusion:

AGAINST ALL ODDS (FROM THE LESSONS OF EFT AND STRINGS), OUR *PARTICULAR* LOW ENERGY WORLD LIKELY ALLOWS US TO GUESS THE FINAL ANSWER.

Or to put it in modern internet speak:

YOU CAN JUST GUESS THINGS.

As I see it, the standard model with all of its weirdness and ad hoc artificial contraptions is the most beautiful piece of differential geometry imaginable. Like finding a DaVinci masterpiece in a junkyard. You just can’t believe it because the setting is all wrong.

So, in my opinion, String Theory drove physics insane with florid hallucinations and violence towards rivals. EFT was like putting it back on track using extremely heavy anti-psychotic medication.

And I dream of one day soon getting it off its meds and curing the delusions with diet (of data from our own particular physical world) and excercise (of scientific judgment, epistemic humility, and decency to colleagues).

5:00 PM · Nov 6, 2025

Eric Weinstein

@EricRWeinstein

Just coming back To this @grok. Any thoughts here? Am I off base? Did I misportray this situation?

5:00 PM · Nov 6, 2025

Eric Weinstein

@EricRWeinstein

Here is what is wrong with Effective Field Theory, to me, as explained by Wheel Of Fortune.

Imagine this puzzle was the information at some low energy (Standard Model), and the number of letters left to find matched the orders of magnitude from where we are to (UV) completion.

Effective Field Theory says “Be modest and learn to live with lack of unique UV completion and a rambling effective Standard Model so many orders of energy away from the Planck Scale because it can’t be guessed from so far away.”

2:31 PM · Nov 7, 2025

Alejandro Rivero

@arivero

@EricRWeinstein it could be interesting if you clarify your position on the EFT doctrine. To me it is basically a "planck-scale first" doctrine, that tells that any experimental result is not important, and than renormalizability of theories is just an amusement.

2:01 PM · Nov 7, 2025

Eric Weinstein

@EricRWeinstein

GU says: “That is eminently reasonable & sober, and is thus good solid science. Now get this defeatist mindset the hell away from me, go peer review each other, and hold my beer. Send lawyers, guns & money: let’s get back to American Cowboy science.”

🤠

2:31 PM · Nov 7, 2025

Eric Weinstein

@EricRWeinstein

When it comes to Ed Witten/Lenny Susskind vs John F. Donoghue/Ken Wilson, I’m just not in that game. Not my colleagues. Not my rodeo.

I belong to the Bruce Willis school of fundamental physics:

“I was always kinda partial to Roy Rodgers actually.”

2:41 PM · Nov 7, 2025

Eric Weinstein

@EricRWeinstein

And @grok, can you make this argument understandable to anyone claiming to be confused by this analogy? Thx partner.

2:54 PM · Nov 7, 2025

Eric Weinstein

@EricRWeinstein

I finally figured out how to describe using just four words what I detest about the defeatism of the modern Effective Field Theory School of theoretical physics:

"Shut up and Regulate."

@grok, may I lean on you to help explain to a general audience? Thanks in advance my silicon friend.

10:45 PM · Nov 12, 2025

Eric Weinstein

@EricRWeinstein

Here is what is wrong with Effective Field Theory, to me, as explained by Wheel Of Fortune.

Imagine this puzzle was the information at some low energy (Standard Model), and the number of letters left to find matched the orders of magnitude from where we are to (UV) completion.

Effective Field Theory says “Be modest and learn to live with lack of unique UV completion and a rambling effective Standard Model so many orders of energy away from the Planck Scale because it can’t be guessed from so far away.”

2:31 PM · Nov 7, 2025

Related Pages

• Theory of Geometric Unity
• Early is another name for wrong
• Geometric Unity Predictions
• I’ve Got a Good Feeling About This
• Ken Wilson
• You Know You’re in GU When