Full Idea
The scientist trying to establish the geography and history of the unobserved portion of the universe must depend upon what he takes to be the laws of the universe.
Gist of Idea
Science depends on laws of nature to study unobserved times and spaces
Source
David M. Armstrong (What is a Law of Nature? [1983], 01.1)
Book Reference
Armstrong,D.M.: 'What is a Law of Nature?' [CUP 1985], p.4
A Reaction
This does seem to be the prime reason why we wish to invoke 'laws', but we could just as well say that we have to rely on induction. Spot patterns, then expect more of the same. Spot necessities? Mathematics is very valuable here, of course.