Objectivism vs. Subjectivism
For ordinary purposes economic things can best be described as
economic, just as blue things can best be described as blue. But
if we must have a second-best description for the benefit of
those who doubt whether they know what is meant by the term
economic, I think we must fall back on “having to do with
the more material side of human happiness,” or more
shortly, “having to do with material welfare.”
Cannan (1922 [1914]) Ch.1.
Here, then, is the unity of subject of Economic Science, the
forms assumed by human behaviour in disposing of scarce
means. … Economics is the science which studies human
behaviour as a relationship between ends and scarce means which
have alternative uses.
Robbins (1932) p.4.