Composite cognition

Cognition whose output emerges from a composite of layers: the human + their thinking model + their AI + their data + their external memory.

The operational criterion (the subtraction test)

A layer belongs to the cognitive system if subtracting it measurably changes the cognitive output. Take away Otto’s notebook — he stops “knowing” where the museum is. Take away a 2026 human’s phone and AI model — they lose numbers, routes, the pace of reasoning. Functionally it is the same amputation.

What it is NOT

Composite cognition does not mean “AI thinks for the human”. The human remains the integrating layer: they choose what matters, bear the responsibility, ask the questions. A composite without that layer has no direction.

The term is introduced operationally in chapter 2; the philosophical foundation — the Extended Mind (chapter 1).