(1) Accurate observer,
(2) Constructive imagination,
(3) Passion for truth.
13. SUMMARY.
(1) Facts are the foundation of all inductive generalizations. Induction is largely a matter of building general notions from individual notions derived from the observation of facts.
(2) Observation is the act of watching the phenomena as they may occur. It involves the voluntary concentration of consciousness on the case in hand.
(3) Experiment is the act of making phenomena occur for the purpose of watching for effects. It is in reality a form of observation which necessitates a manipulation of circumstances.
(4) The average man is not given to careful observation. The rules adopted by scientific observers are: (1) The observation should be precise; (2) should concern only the material circumstances; (3) should be varied; (4) should be isolated.
For the sake of precision many instruments have been invented and methods devised; notably instruments for accurate measurements, such as the balance and thermometer, and methods like the method of averages.
Frequently a situation may be so complicated as to demand a “preadjustment of attention.” With the untrained this very preadjustment may lead to serious error.