Dialogue VI — On c (and Why It Isn’t a Cosmic Speed Limit)

Characters:

Professor Quillibrace — master of relational ontology

Mr Blottisham — confidently wrong, loud, impatient

Miss Elowen Stray — curious, inclined to understand, occasionally amused

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Blottisham:

Enough of this! You keep saying c is not a speed, not a limit, not a thing “out there.” What is it then? Surely it must be… something!

Quillibrace:

It is precisely that — not a something. c is a constraint within the system of relations we use to describe spacetime, mass, and energy. It ensures that the system does not tear itself apart when perspectives shift.

Elowen:

So it’s not a fact about the universe, but a requirement for coherence within our description?

Quillibrace:

Exactly. Invariants like c are conditions for perspectival stability, not discoveries of hidden cosmic features. They are what allow multiple observers to agree within a system, not what composes the universe itself.

Blottisham:

But it has units! Metres per second! That must mean it travels somewhere!

Quillibrace:

No, Blottisham. The units are a feature of the system — a way of relating distance and time in a coherent description. They do not imply that c “exists” as a moving entity.

Elowen:

And E=mc²? That’s often treated as mass “really becoming” energy. How does it fit?

Quillibrace:

Mass and energy are perspectives on the same system, instantiated under different cuts. c² is the factor that preserves identity across those cuts. Nothing is being converted; rather, the system is being related consistently.

Blottisham:

So all those talks about cosmic speed limits, mass–energy conversion, spacetime stretching… they’re overreaches?

Quillibrace:

They are ontological inflations. c does not inhabit the world; it inhabits the rules that let our description hang together. To treat it as a cosmic constant “out there” collapses the distinction between structured potential (the system) and instantiated phenomena (the events we observe).

Elowen:

So if c disappeared tomorrow, the universe wouldn’t break — our description would?

Quillibrace:

Precisely. c is a cut, a condition internal to a system of relations. It is not a feature waiting to be found; it is a requirement for coherent discourse about what we call spacetime.

Blottisham:

Then it’s… a prohibition? A rule?

Quillibrace:

Yes. And a quiet one. Unlike the loud proclamations of a “speed limit,” it simply ensures that our perspectives remain commensurable. It is what we are not allowed to change if we want our descriptions to make sense.

Elowen:

And that subtlety… it reframes everything. Quantum-classical puzzles, collapse debates, the mystique of equations…

Quillibrace:

It does. Physics remains exacting and difficult. What changes is the story we tell — one that honours constraints without mistaking them for substances, potentials without mistaking them for particles, invariants without mistaking them for ultimate truths.

Blottisham (muttering, flustered):

I suppose… I could live with that. But it still makes my head spin.

Elowen (smiling):

And perhaps it should.

Quillibrace:

Indeed. Coherence is rarely comfortable, but always precise.