Definition
Plain language
A sudden, sharp change in how a system behaves when a parameter crosses a threshold.
As stated in the literature
A qualitative regime change in a system's behavior as a control variable passes a critical value, often non-smooth; invoked as analogy (not claim) in the EDRM paper for entropy-trajectory clustering.
Also called: phase transitions
Why it matters: Recognizing sharp regime changes in training dynamics or capabilities helps explain why small parameter changes can produce big behavioral jumps.
For example, water doesn't gradually freeze — it stays liquid until 0°C and then suddenly turns to ice.
Heard on the show
“That's a behavioral phase transition.”Episode 008 — Why Long-Horizon AI Agents Get Stuck, and a Milestone-Based Fix That Helps