Round Table Discussion 1 Chair — Alex Rosenberg

Elizabeth Lloyd Well, no, I had a specific idea of reductionism in my talk which actually didn t address the Newtonian question, but rather sees reductionism as an approach or an attempt to explain phenomena in terms of certain types of entities and their properties at these levels. A reductionist 

Edited by M.H.V. Van Regenmortel and David L. Hull 2002 John Wiley Sons, Ltd 

Claude Debru My point is not a comment on reductionism, but a comment on the movement of the planets. We know since Poincare that the movement of the planets is chaotic, which means that it would be predictable if we would have the knowledge of the initial conditions of the system. But in the ignorance of this data of the initial conditions, it remains unpredictable. So I think this qualifies some ideas, perhaps. I don t know how it fits into the framework about reductionism - because you mentioned the movement of the planets. 

Alex Rosenberg My inclination is to say that it doesn t because most reductionists are perfectly happy to accept chaotic phenomena as an epis-temic limit on predictability and not a limit on either on the understandability of a system or on the degree of its determinism, whether upward in its causal determinism or not. 

Michel Morange I didn t get the sense of downward causation. What is really downward or upward causation  

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Round Table Discussion 1 Chair — Alex Rosenberg... 

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