Full Idea
Many physical phenomena that are often taken to be paradigms of reducibility (e.g. temperature) are in fact multiply realizable.
Gist of Idea
Temperature (etc.) is agreed to be reducible, but it is multiply realisable
Source
David J.Chalmers (The Conscious Mind [1996], n 2.20)
Book Reference
Chalmers,David J.: 'The Conscious Mind' [OUP 1997], p.364
A Reaction
So multiple realisability isn't such a big problem for physicalism. I take it, though, that all hot things have some physical type of event in common (a level of molecular energy). Finding the level of commonality is the challenge.