To know the exact meaning of the concepts one is using, one must know their
correct definitions, one must be able to retrace the specific (logical, not
chronological) steps by which they were formed, and one must be able to
demonstrate their connection to their base in perceptual reality.
When in doubt about the meaning or the definition of a concept, the best method
of clarification is to look for its referents—i.e., to ask oneself: What fact
or facts of reality gave rise to this concept? What distinguishes it from all