Full Idea
Most of the propositions we think of as being (or as expressing) genuine laws of nature seem to describe only the behaviour of ideal kinds of things, or of things in ideal circumstances.
Gist of Idea
Laws of nature tend to describe ideal things, or ideal circumstances
Source
Brian Ellis (The Philosophy of Nature: new essentialism [2002], Ch.5)
Book Reference
Ellis,Brian: 'The Philosophy of Nature: new essentialism' [Acumen 2002], p.91
A Reaction
Ellis this suggests that this phenomenon is because science aims at broad understanding instead of strict prediction. Do we simplify because we are a bit dim? Or is it because generalisation wouldn't exist without idealisation and abstraction?