Full Idea
It is not the penicillin that causes the pneumonia to disappear, but what the penicillin does.
Gist of Idea
Penicillin causes nothing; the cause is what penicillin does
Source
Machamer,P/Darden,L/Craver,C (Thinking About Mechanisms [2000], 3.1)
Book Reference
-: 'Philosophy of Science' [-], p.6
A Reaction
This is a very neat example for illustrating how we slip into 'entity' talk, when the reality we are addressing actually concerns processes. Without the 'what it does', penicillin can't participate in causation at all.