PhronesisThe shape
Positive feedback is an output that loops back to increase itself. Norbert Wiener’s cybernetics was mostly about the other kind — the regulating, deviation-correcting loop of a thermostat (Cybernetics, 1948). Magoroh Maruyama named the complement the “second cybernetics”: deviation-amplifying mutual causal processes — loops that grow their own departures (American Scientist 51, 1963). “Circulation increases circulation” is one line of the second kind. Put more of the carrier into a flow, the flow grows, and the larger flow moves more carrier. It is a loop, not a rate — which is why the earlier phrasing, more ions = faster, was the weaker and wrong version, and this one holds.
The spark
Take a gas and a strong electric field. One free electron is pulled along, and somewhere it hits a neutral atom hard enough to knock a second electron loose. Now there are two carriers; each is pulled along and does the same; two becomes four, four becomes eight. This is the Townsend avalanche (J. S. Townsend, The Theory of Ionization of Gases by Collision, c. 1910): charges in circulation make more charges circulate, exponentially. It is not a metaphor for electrical breakdown — it is electrical breakdown, the physics under a spark, an arc, a stroke of lightning.
The bloodstream
Now change everything about the substrate and keep the shape. Retain sodium and the body retains water to match it, to hold the concentration steady; the added water raises blood volume; higher volume raises the pressure and the amount the heart moves each minute. This is the spine of Arthur Guyton’s renal–body-fluid account of long-run blood pressure (Guyton, “Blood pressure control,” Science 252, 1991), and it is the reason dietary salt raises blood pressure. More ions in circulation, more circulation — no electrons, no field, the same loop.
The ceiling
Here is the part the slogan drops, and the reason to write it down. A deviation-amplifying loop never runs free. It ends one of two ways. It saturates: the avalanche runs out of neutral atoms to ionize and the current plateaus; sodium’s effect is blunted as the kidney and vasculature push back. Or it runs away and collapses: the spark tips into an arc that quenches; blood pressure that keeps climbing is not vigor but hypertension, and the vessel, the kidney, the heart eventually give. Every self-amplifying loop pays for its amplification, and the bill comes as a ceiling or a crash.
The honest claim is never “increases circulation.” It is “increases circulation — for a while, up to a wall.”
The same loop, upstairs
The reason to keep this one is that the site keeps finding the loop in the nervous system. Coherence via connection is deviation-amplifying: connection breeds coherence, coherence makes more connection possible, and two nervous systems in genuine contact couple more the longer they stay in contact — the co-regulation and hyperscanning coupling this site is careful not to over-read. And it carries the same ceiling. Coupling that runs away is enmeshment, folie à deux, the loss of the second term each system needs to read itself against. So “circulation increases circulation” may simply be the general form of the house thesis — said in ions and blood rather than in nervous systems. Same loop, same ceiling, same collapse when it runs free.
What this is, and is not
It is not a claim that a spark, a bloodstream, and a bond share a mechanism. They do not. It is a claim that they share a shape — deviation-amplifying feedback with a bound — and that the shape is real, old, and general (cybernetics; autocatalysis in chemistry, where a product speeds its own making). The whole contribution is the recognition and the ceiling: not a new physics, and not a licence to read every rising thing as this loop. A shape, grounded three times and bounded once. Where more carrier does nothing, or only hurries a one-way flow, this is not the loop — and the note does not reach for it there.
Rests on: Maruyama, “The Second Cybernetics” (American Scientist 51, 1963); Wiener, Cybernetics (1948); Townsend, avalanche ionization in gases (c. 1910); Guyton, renal–body-fluid control of arterial pressure (Science 252, 1991). Offered, not proven: reading coherence-via-connection as an instance of the same shape is a proposal about form, not a demonstration of shared cause.
Kin to Coherence Is the Second Term (the dyadic reading) and Blaming the Grain (the other amplifier — criticality, where the trigger’s size stops mattering).