Taboo "emotion".

By emotion, I mean, "that which controls the macro-physiological state of the body across multiple control systems, whose effects may be observed through kinesthetic awareness, and which is not a product of direct conscious effort to influence that state."

Or, in simpler words, "feelings". ;-)

Evolutionarily, I propose that the function of emotion is to prepare the body for co-ordinated action of some kind - for example, fear prepares for fight/flight and triggers heightened sensory focus.

Other emotions are more cerebral (e.g. the "aha" sensation), but still can be perceived in physical form, often still having externally visible effects, even to the naked eye.

When you describe the quite real operations performed by human mind, consisting in assigning properties to things and priming to see some properties easier or at all, you bless this description with the action of emotion-substance for some reason.

The reason is that brains were not created for us to perform reasoning, they were created to classify things by emotion -- that is, to prepare the body for responses appropriate to recognized external events. It's important to remember that thinking arose after simple memory-prediction-action chains, and that it's built on top of that legacy system. That's why emotion (using the definition I gave above) is critical: tagging things with emotions and replaying those emotions upon recall is the primary substance and function of brains.

Yes, there are goal subsystems and all that... but that's another system (like "thinking") that's layered on top of the memory-prediction-action chain.

For example, you talked about good and bad emotions in the past, and it's OK once you specify a model which is driven by good and bad emotions instead of more explicit expected terminal utility computation.

Certainly -- that's later in the sequence. It was going to be next, but yours and Yvain's comments make me think that maybe I need to get a bit more explicit about the evolutionary chain here, including the memory-prediction-action core, although maybe I can work that in at the beginning.