Coevolution, Emergence, Stigmergence Camille Roth Dept of Social and Cognitive Sciences Universita` di Modena e Reggio Emilia

ECLT — April 10, 2006

Appraising levels Relationships between different levels Dualism, reductionism? Emergentism? → is the emergent level an epiphenomenon or does it enjoy causal powers? Levels as observations Rather, different modes of access to a same process; not coexisting levels (Bitbol, 2006).

thermometer temperature of gases

molecular description x

“Observationism” and modeling

Reductionist attitude Given η, find P such that P(L) = H, λ such that P ◦ λ(L) = η(H) Strong change in viewpoint 1

No “substantial” reality of levels, but an observational reality only.

2

No reciprocal causation of higher- and lower-level, but simply informational links.

3

For some phenomena improving dynamics is not sufficient, and rethinking levels is mandatory.

Co-evolution and stigmergence

Two kinds of influence 1

Upward/downward (synchronic) informational dependence of a level on another

2

Co-evolution of objects through classical causation

Stigmergence Agents build artifacts, which in turn influence them, because they exist outer of agents Stigmergence is related to (diachronic) co-evolution