Signal
What one living unit releases or transmits so that another can be affected across a boundary: the elementary event of interaction between Cells.
Status: Working concept under the biology lens. Primary science reading: intercellular signaling / cell communication. Analogy, not isomorphism. Follows Single-scale Metabolism; precedes Recognition and Coupling.
Exchange across membranes.
In biology, cells do not only maintain themselves in isolation. They emit and receive signals: molecules, electrical events, mechanical cues that carry information or force across the space between living units.
In Identity Engineering, Signal names that elementary interactive event under the biology lens. AfterMetabolismhas prepared a Cell to process and release, Signal is what actually crosses or is offered at theBoundarytoward another living unit.
Operationally this is the closest biology-lens counterpart to the framework and OS notion ofInteraction Signal: a structured act that can be admitted, rejected, or partially applied under membrane policy, and that can leave a geometric trace in the receiver.
- An interactive event: something offered or transmitted from one Cell toward another (or into a shared medium).
- Boundary-crossing content: not the membrane itself, but what the membrane may pass, block, or transform.
- Input to another metabolism: a received signal can be metabolized into geometry, state change, or further signaling.
- First step of Interactive scale: before stable Coupling, there is at least a signal event.
- Not Recognition.Recognition decides how a signal is classified and whether it may act. Signal is the event being classified. Recognition follows as the next concept.
- Not Coupling.Coupling is sustained structural or functional linkage between units. A signal can be one-shot; coupling is ongoing relation.
- Not Metabolism.Metabolism is the internal process of one Cell. Signal is what leaves or arrives at the membrane in relation to another unit.
- Not the full relationship.One signal does not yet make a bond, a collective, or mutual ownership.
- Not a claim that all identity interaction is molecular.Intercellular signaling is the science reading. The framework maps structure: discrete interactive events across boundaries.
From Single into Interactive
- Single: Gene → Boundary → Cell → Metabolism
- Signal — elementary exchange event
- Recognition (next) — how the receiver classifies and admits
- Coupling (after) — sustained link built from repeated, recognized exchange
Signal answers: what crosses between living units?Recognition will answer: who or what is allowed to act?
What we work on
- Make signals explicit: what is being sent, by whom, toward whom, under what claim?
- Separate event from bond: do not treat every message as Coupling or as shared Identity.
- Respect Boundary on both sides: sending and receiving are membrane events, not automatic takeover of the other Cell.
- Expect metabolic consequence: a real signal changes the receiver's process, or it was only noise.
Primary discipline: intercellular signaling / cell communication(ligands, messengers, directed cues between cells). Recognition and Coupling complete the Interactive scale next.