Different means of determining errors.
Distinguishing how little from how much we do not understand.
Karl Popper on what constitutes reliability in experimental science:
"the criterion of the scientific status of a theory is its falsifiability, or refutability, or testability."
These are the means of moving up the pyramid from knowing appearances to understanding isolated causes or connected interrelations.
3 possible experimental outcomes are:
+ hypothesis is confirmed; yes
- the hypothesis is denied; no
ø the experiment is inconclusive!
Karl Popper, Conjectures & Refutations, p. 37
The necessity of doubt.