December 12, 2025
SIGFPT Meeting: Actor Models and Protocol Theory
Participants: _vgr, mtraven, giovanni.merlino, simpalaxy, milieu.us, ediblebadger, zoesh
The SIGFPT group held a session on actor models, exploring their theoretical foundations, relationships to other computational paradigms, and applications. The discussion centered on whether asynchronous communication should be the primitive with synchrony built on top (actor model approach) or vice versa (process calculi). Multiple participants argued that asynchrony is more fundamental, with zoesh framing this through a Coasean economic lens where synchrony emerges when coordination costs of asynchrony become too high. The group reviewed classical papers including Gul Agha's actor language overview and Kornfeld & Hewitt's scientific community metaphor. Practical applications were discussed, including ediblebadger's work on probabilistic microsimulations for population health policy analysis using the vivarium framework, and broader interest in agent-based modeling for capturing emergence and complex dynamics. The conversation touched on ideological dimensions of this research tradition, with participants noting both anarchist and market-oriented (Agoric Systems) influences that appeal across ideological lines.
- Actor models requiring explicit synchronization construction represent a design choice with tradeoffs compared to process calculi with built-in synchrony, with asynchrony arguably being more fundamental to how the world operates.
- The natural world defaults to asynchronous states, with synchrony emerging only when the coordination costs of asynchrony become prohibitively high, suggesting actor-based approaches better reflect reality than synchronous-first models.
- Bottom-up, agent-based modeling approaches enable exploration of emergence and complex dynamics, though computational burden has traditionally limited scaling to real-world system fidelity.
- Protocols can emerge as mechanisms for negotiating between individuals with mixed viewpoints by defining starting states, processes, and end states that establish agreement.