There are three principal means of acquiring knowledge. . . observation of nature, reflection, and experimentation. Observation collects facts; reflection combines them; experimentation verifies the result of that combination.  -   Denis Diderot     Quotes
There are three principal means of acquiring knowledge. . . observation of nature, reflection, and experimentation. Observation collects facts; reflection combines them; experimentation verifies the result of that combination. Denis Diderot
 Facts