Full Idea
When the observer shifts his attention from one level of organisation to the next, as from physics to chemistry, he expects to find obedience to all the laws of the levels below.
Gist of Idea
If observation goes up a level, we expect the laws of the lower level to remain in force
Source
Edmund O. Wilson (On Human Nature [1978], Ch.1)
Book Reference
Wilson,Edward O.: 'On Human Nature' [Penguin 1995], p.11
A Reaction
This seems to state a necessary condition of reduction, but not a sufficient one. Wilson points out that new phenomena emerge at higher levels. This principle is similar to Hume's argument against miracles. You don't easily overthrow basic laws.