Full Idea
According to one tradition, necessary truth demarcates philosophical from empirical inquiry. Science identifies contingent aspects of the world, whereas philosophical inquiry reveals the essential nature of its objects.
Gist of Idea
Maybe what distinguishes philosophy from science is its pursuit of necessary truths
Source
Theodore Sider (Reductive Theories of Modality [2003], 1)
Book Reference
'The Oxford Handbook of Metaphysics', ed/tr. Loux,M /Zimmerman,D [OUP 2005], p.183
A Reaction
I don't think there is a clear demarcation, and I would think that lots of generalizations about contingent truths are in philosophical territory, but I quite like this idea - even if it does make scientists laugh at philosophers.