Theories are like a stairway; by climbing, science widens its horizon more and more, because theories embody and necessarily include proportionately more facts as they advance.
The fact that knowledge endlessly recedes as the investigator is about to grasp it is what constitutes at the same time his torment and happiness.
Particular facts are never scientific; only generalization can establish science.
The first requirement in using statistics is that the facts treated shall be reduced to comparable units.
A fact in itself is nothing. It is valuable only for the idea attached to it, or for the proof which it furnishes.