From Human Action — surrounding passage

A statement proclaimed without such a connection is arbitrary and floats in midair. It is impossible to deal with a special segment of economics if one does not encase it in a complete system of action. The empirical sciences start from singular events and proceed from the unique and individual to the more universal. Their treatment is subject to specialization. They can deal with segments without paying attention to the whole field.

“The economist must never be a specialist. In dealing with any problem he must always fix his glance upon the whole system.”

Historians often sin in this respect. They are ready to invent theorems ad hoc. They sometimes fail to recognize that it is impossible to abstract any causal relations from the study of complex phenomena. Their pretension to investigate reality without any reference to what they disparage as preconceived ideas is vain. In fact they unwittingly apply popular doctrines long since unmasked as fallacious and contradictory. 11.