Unlike Walras’s “pure science” view, Marshall ([0000]
0000) saw “tendencies” toward equilibrium that were
discoverable by the science of economics. These tendencies
could be stated as normative “laws” if the caveat, ceteris paribus were fully understood by the reader. He found little use
for distinctions between unproductive and productive labor.
But much like Mill ([0000] 0000, 00), Marshall did adopt the
convention of using the word “productive, by itself . . . to
mean productive of the means of production, and of durable
sources of enjoyment,” though he cautioned, “It is a slippery
term, and should not be used where precision is needed.