The Parable of the Pebbles

The quibble over definition, when you can replace rationality with utility and ditch the whole page of text.

Generally, we do things, because they work (produce results perceived as beneficial) and do repeatedly and reproducibly so, system or no system.

Now, this is not exactly strictly rational as it depends on self-referential definition of success or benefit, which is always heuristic and limited.

Ultimately, this reduces to biological and conditioned instincts. These can change too.

Cognitivism can be rescued by noting that some things change slower and less chaotically than others, these are easier to study - and that all physical systems still have a quantifiable determinism.

Sorry about breaking nebulosity by retreating to chaos. "Because" in backwards direction is hemmed in by it. The truth is measured as information. And ten the may be true non-determinism possible but due to chaos not leading to true unpredictability.