Berlin 2012 – scientific programme

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AGPhil: Arbeitsgruppe Philosophie der Physik

AGPhil 7: Philosophy of Science

AGPhil 7.4: Talk

Wednesday, March 28, 2012, 18:45–19:15, H 2033

Are classical forces relations or dispositions? — •Johannes Röhl — Universität Rostock, Rostock, Germany

Realists about Newtonian Forces are confronted with the task of assigning an ontological category to these entities. I identify four main features forces must have according to a standard view of Newtonian mechanics: causal efficacy, directionality (vectorial character), superponibility and dependence on non-force entities.

The two main proposals in the debate, forces as relations and forces as dispositions or causal powers, both appeal to intuitions from Newtonian mechanics, but face considerable difficulties in detail. The dispositional conception may not be able to accomodate the directionality and the symmetrical dependence of a force on the bodies between it acts. The relational account seem to lead to revisionary accounts of causation and it is not clear how the superposition of components forces and the resulting force are to be understood.

I suggest an alternative approach that takes forces as intermediaries in a chain of dispositions and their manifestations. A force is a manifestation of a disposition, but has itself dispositional character as it causes accelerations. The relational aspect of forces can be construed as an emergent feature of the whole interaction situation. The component and resultant forces can also be accomodated by this model.