Extended mind

The extended mind thesis is the philosophical claim that cognitive processes extend beyond the boundaries of the individual brain to include tools, technologies, and environmental structures. Proposed by Andy Clark and David Chalmers in their 1998 paper The Extended Mind, the thesis argues that if a resource is functionally integrated with cognitive processes in the right way, it should be considered part of the cognitive system itself — not merely an external aid. The canonical example is Otto, who uses a notebook to compensate for memory loss: the notebook plays the same functional role that biological memory plays for others, and thus (Clark and Chalmers argue) Otto's mind extends to include it.

The thesis challenges the brain-bound conception of cognition dominant in cognitive science and connects to distributed cognition, situated learning, and the study of human-computer interaction. If accepted, it has radical implications for how we understand artificial intelligence: a sufficiently integrated AI assistant would not be a tool but a genuine extension of the user's cognitive architecture.