Noether, Symmetry, and Why TFP Has Its Own Conservation Law
by John Gavel
If you’ve spent any time around theoretical physics, you’ve heard the name Emmy Noether. She’s the mathematician who quietly rewrote the rules of the universe with one deceptively simple idea:
Every symmetry of a system gives rise to a conserved quantity.
That’s it. That’s the whole theorem. But it’s also the backbone of modern physics.
Time‑translation symmetry gives you conservation of energy. Spatial translation gives you momentum. Rotation gives you angular momentum.
Noether basically said: “If the laws don’t change when you wiggle the system in some way, then something must stay constant.”
And that idea has been sitting in the back of my mind for years as I’ve been building TFP — because TFP is nothing but symmetry and constraint. It’s a universe made of binary relational differences, closure rules, and a 1‑dimensional causal engine. If Noether is right (and she always is), then TFP should have its own conservation laws baked right into its algebra.
And it does. Let me show you how.
The Symmetry: Global Flip
In TFP, every site has a binary state \(F_i \in \{0,1\}\) (or \(\pm 1\), depending on representation). There’s a very simple symmetry that the entire system respects:
Flip every bit.
Turn every 0 into 1 and every 1 into 0. Or multiply every \(F_i\) by \(-1\). Same thing in \(\mathbb{F}_2\).
This is the global flip symmetry, and it’s the most primitive gauge symmetry in the entire framework. It’s the statement that the universe doesn’t care whether you call one side “+” or “–”. Only the differences matter.
What does it mean for the update to “respect” the flip?
Think of it this way:
- Flip all bits.
- Run the update rule.
- Compare to: run the update rule first, then flip all bits.
If you get the same result either way, the update respects the symmetry.
Formally:
\[ U(g(F)) = g(U(F)). \]
That’s commutativity — the order doesn’t matter.
But to actually get a conservation law, we need one more structural assumption.
The Conserved Quantity: Global Parity
Define the parity functional:
\[ P(F) = \bigoplus_{i \in V} F_i. \]
This is just the XOR of all the site states. It’s the “total oddness” of the configuration.
Why parity specifically?
Because it’s the only global quantity that:
- Depends on all sites
- Transforms in a simple, predictable way under the global flip
- Lives naturally in \(\mathbb{F}_2\)
- Can remain invariant under a symmetry‑respecting update
Any other linear functional either:
- isn’t global,
- isn’t invariant, or
- isn’t conserved.
Parity is unique. That’s why Noether picks it out.
The Formal Proof (TFP Noether Theorem)
Here’s the exact theorem inside TFP’s algebraic structure — now stated correctly.
Theorem (TFP Noether — Corrected).
Given:
- Configuration space \(M = (\mathbb{F}_2)^V\)
- Global flip symmetry \(g(F) = F \oplus \mathbf{1}\)
- Update rule \(U: M \to M\) that is \(\mathbb{F}_2\)-linear
- And satisfies \(U(g(F)) = g(U(F))\)
- Parity functional \(P(F) = \bigoplus_i F_i\)
Then:
\[ P(U(F)) = P(F) \]
In words: if the update rule is linear and respects the global flip symmetry, then global parity is conserved.
Why we need linearity
Without linearity, the commutation condition alone does not force parity conservation. Linearity ensures:
\[ U(F \oplus \mathbf{1}) = U(F) \oplus U(\mathbf{1}) \]
and lets us relate \(P(U(g(F)))\) back to \(P(U(F))\) in a controlled way.
Proof
Start with commutation:
\[ U(g(F)) = g(U(F)). \]
Using linearity:
\[ U(F \oplus \mathbf{1}) = U(F) \oplus U(\mathbf{1}). \]
So:
\[ U(F) \oplus U(\mathbf{1}) = U(F) \oplus \mathbf{1}. \]
Thus:
\[ U(\mathbf{1}) = \mathbf{1}. \]
Now apply parity:
\[ P(U(F \oplus \mathbf{1})) = P(U(F) \oplus U(\mathbf{1})) = P(U(F)) \oplus P(U(\mathbf{1})). \]
But \(U(\mathbf{1}) = \mathbf{1}\), so:
\[ P(U(\mathbf{1})) = P(\mathbf{1}) = |V| \mod 2. \]
On the other hand:
\[ P(g(U(F))) = P(U(F) \oplus \mathbf{1}) = P(U(F)) \oplus (|V| \mod 2). \]
Equating both expressions gives:
\[ P(U(F)) \oplus (|V| \mod 2) = P(U(F)) \oplus (|V| \mod 2). \]
Subtracting the common term yields:
\[ P(U(F)) = P(F). \]
Parity is conserved. ∎
What This Means Concretely
Imagine a TFP network with 12 sites.
Right now, 7 of them are in state “1” — an odd number. So:
\[ P(F) = 1. \]
You run the update rule. Bits flip. Local patterns shift around. But when you count the 1’s again, something interesting happens:
- It might jump to 3
- Or 9
- Or 11
- Or 5
- Or 13
- Or even stay at 7
The actual number can go up, down, or bounce around unpredictably.
But one thing never changes:
It always stays odd.
If you start with even parity, the same thing happens:
- 8 → 10 → 6 → 12 → 4 → 14 → 2 → 8
Chaotic, nonlinear, unpredictable — but always even.
That’s what conservation means here.
Not that the number of 1’s stays the same. Not that the system evolves smoothly. Not that there’s a pattern.
Just this:
The parity — the XOR of all bits — never changes.
How This Differs From Classical Noether
Classical physics:
- Continuous symmetry (rotate by any angle \(\theta\))
- Smooth manifolds and derivatives
- Local currents \(J^\mu(x)\) with \(\partial_\mu J^\mu = 0\)
- Conserved charge \(Q = \int J^0 d^3x\)
TFP:
- Discrete symmetry (flip all bits, period)
- Finite states and XOR algebra
- Global charge \(P = \bigoplus_i F_i\)
- Conservation is direct: \(P(t+1) = P(t)\)
Same principle — symmetry gives conservation. Different implementation — calculus vs. algebra. Same depth.
Why This Matters for TFP
So, the work here reflects how symmetry and structure constrain the flow of information in TFP — directly, without extra assumptions. It is how symmetry and linearity limit the degrees of freedom.
- The global flip symmetry is the most primitive gauge symmetry in the model.
- The update rule respecting that symmetry is the discrete analogue of “the laws of physics don’t depend on your coordinate choice.”
- The conserved parity is the discrete analogue of a Noether charge.
I wonder whether Noether’s framework would predict the same outcome here — or whether discreteness changes what symmetry means at a fundamental level.
I also keep coming back to the way physics treats continuity. I’m not questioning continuity in the calculus sense. I’m questioning why “continuous evolution” is taken as a basic assumption at all. No one really justifies it. In TFP, one state simply follows another. That’s the whole story.
And yet, when we look at physics, we don’t see an unconstrained continuum. We see a sharply reduced space of allowed behaviors: conservation laws, quantization, symmetry restrictions. It looks less like a smooth continuum and more like a structured, discrete system.
In that sense, the continuum steps in as a kind of metaphysical middle‑man. The real question is about the directness of relation — whether two abstractions can relate without gaps, without a continuum filling in the explanation for us. Relation itself is the fundamental entity, not something derived from an underlying flow.
So the deeper question for me is whether continuum physics is just an approximation of something fundamentally discrete. But if we remove the continuum entirely, are we left with explaining what “is” without slipping into another layer of abstraction or infinite regression?
Maybe this is simply a different foundation for stating physics. I’m always questioning on how to express reality without introducing new assumptions that are just as metaphysical as the ones I’m questioning.
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