I argue that a scientific explanation of an empirical phenomenon consists in claiming that this phenomenon obeys at least one kind of objective necessity, which satisfies the methodological criterion of falsifiability. Consequently, I reject the relevance of the notion of probabilistic explanation — which does not imply that I would argue that probalistic modeling is useless with respect to any aim (specifically non-exaplanatory aims).
This note presents two kinds of objective necessity. Let p be an empirical phenomenon.
- a => p. If a exists such that if a occurred, then p occurred, a is a sufficient condition of p. An observation of form « a and non-p » is a falsifier of the sufficient condition a.
- p => b. If b exists such that if p occurred, then b occurred, b is a necessary condition of p. An observation of form « p and non-b » is a falsifier of the necessary condition b.
If one knows a sufficient condition a of p, one is able to get p to occur if one is able to get a to occur (predictive explanation). To explain why p occurs consists in stating that a sufficient condition is met.
If one knows a necessary condition b of p, one is able to prevent p from occurring if one is able to prevent b from occurring (preventive explanation). To explain why p does not occur consists in stating that at least one of its necessary conditions is not met.