Intelligence is the ability to make rare but valid futures more likely.

So an intelligent system is “thermodynamically intelligent” when it uses information and control to make a rare but valid outcome much more likely.

as per this paper.

Most existing intelligence measures judge task success, but they do not explain what brains, LLMs, controllers, and physical information engines have in common.

The paper’s answer is that an intelligent system models the world with itself inside it, then uses that model to choose actions that change what futures become likely.

A future counts only if it is rare under normal passive behavior and still valid, so random strange outcomes do not get counted as intelligence.

The authors turn this into a measure called rare-valid lift, which asks how much more often a system produces those unlikely but acceptable futures than a passive baseline would.

They show that high lift is impossible unless the system can accurately spot the rare valid futures, and high spotting accuracy can nearly produce high lift when the system can act well.

The main point is that intelligence becomes a physical probability-shifting process, not just a score on tests or a label for human-like behavior.

----

arxiv. org/abs/2606.20231

Title: "Thermodynamic Measure of Intelligence"