Cognitive Homology Needs a Trajectory: Active Memory Engineering as the Fourth Dimension of Cognitive Ontology

Krickel and Goddu propose a developmental account of cognitive ontology built around the notion of homology — cognitive categories should be individuated, on their account, the way biological categories are: by tracking continuities of underlying generative mechanisms across brain, behavior, and environment. Their proposal extends Khalidi's (2023) influential work on cognitive ontology by importing a methodologically rigorous criterion from evolutionary-developmental biology. This commentary argues that the proposal is conceptually deep and methodologically valuable, but incomplete in a specific and remediable way. The triad of brain, behavior, and environment, as currently articulated, operates at the level of structural correspondence. It does not yet specify the temporal conditions under which a system can remain coherently identifiable across time. I argue that cognitive homology, to do the work Krickel and Goddu need it to do, requires a fourth dimension: trajectory persistence under environmental memory coupling. Active Memory Engineering (AME) is introduced as the framework that supplies this dimension. Drawing also on Vetter's (2015, 2026) dispositional metaphysics, I argue that cognitive categories are not statically possessed but earned through the active maintenance of the dispositions that constitute them. The relationship between cognitive homology and AME is one of complement, not competition: where homology tells us when two cognitive categories share an identity, AME tells us when a cognitive system has earned the temporal coherence required for any such identity to be carried in the first place.