Physical Hallucination

Problem

The model has no faithful internal model of physics, so it can emit a command that reads as correct and is phrased with full confidence yet cannot be executed. Examples are an unreachable arm pose, a dynamically infeasible motion, a path through an obstacle, or a setpoint inconsistent with the plant's current state. Because the command is syntactically valid and confident, downstream systems that trust the policy pass it through to actuation, where it fails, damages equipment, or creates a hazard. The failure is grounded in the physical world the model cannot perceive faithfully, not in missing facts or tools.

Solution

Treat every command from the policy as a proposal to be checked against physics, not an instruction to execute. Insert a feasibility stage between policy and actuator that grounds the candidate action in the current scene and the system's kinematic, dynamic, and state limits. That stage can predict the action's affordance from perception, or roll it out in a simulator or world model, and it rejects or repairs any action the environment cannot support. Only feasible, in-state commands reach the controller; infeasible ones are discarded, re-planned, or escalated. The check is independent of the policy's own confidence, so a fluent but impossible command cannot pass merely by being well-phrased.

When to use

• Recognising this failure when an embodied or process-control agent issues commands the physical system cannot actually perform.
• Reviewing a policy-to-actuator path that has no feasibility or affordance check between the model and the hardware.
• Diagnosing actuation faults, collisions, or unsafe setpoints that trace back to confidently-phrased but impossible commands.