Full Idea
All true and fruitful natural philosophy hath a double scale or ladder, ascendent and descendent, ascending from experiments to the invention of causes, and descending from causes to the invention of new experiments.
Gist of Idea
Science moves up and down between inventions of causes, and experiments
Source
Francis Bacon (The Advancement of Learning [1605], II.VII.1)
Book Reference
Bacon,Francis: 'Advancement of Learning/New Atlantis' [OUP 1966], p.106
A Reaction
After several hundred years, I doubt whether anyone can come up with a better account of scientific method than Bacon's.