All other aspects and characteristics of science can be understood directly when we understand that observation is the ultimate and final judge of the truth of an idea.
It is a pleasure to stand upon the shore, and to see ships tost [tossed] upon the sea: a pleasure to stand in the window of the castle and to see the battle and the adventures thereof below: but no pleasure is comparable to the standing upon the vantage ground of truth (a hill not to be commanded and where the air is always clear and serene), and to see the errors, and wanderings, and mists, and tempests, in the vale below.