One possible definition is to look for things which are more optimized than any simple mechanism you can imagine for performing a task. So, e.g. Kasparov is great at playing chess, as an amateur you can verify this by noting that any plan you can come up with will tend to do worse than Kasparov’s plans(with high probability). In some sense this is an observer-relative definition, but it can be made more objective by considering the minimally-complex program that can match a given level of performance on a task, parameterized by e.g. Levin complexity. See this comment.
One possible definition is to look for things which are more optimized than any simple mechanism you can imagine for performing a task. So, e.g. Kasparov is great at playing chess, as an amateur you can verify this by noting that any plan you can come up with will tend to do worse than Kasparov’s plans(with high probability). In some sense this is an observer-relative definition, but it can be made more objective by considering the minimally-complex program that can match a given level of performance on a task, parameterized by e.g. Levin complexity. See this comment.
“optimised agent” appears not to be a tautology.