as a science which can give us positive concrete "laws". The
general reason is, I should say, that although its first principles may
be true descriptions of facts, and any denial of them, or any
inconsistent applications of them, may lead us into error, they are yet
far from sufficient descriptions. They omit some considerations which
are relevant in any concrete case; and the facts which they describe
are so complex that, even when we look at them consistently and follow
the right clue, we cannot solve the complicated problems which occur.
It may be worth while to insist a little upon this, and to apply it to
one or two peculiar problems.

Let me start from the ordinary analogy. Economic inquiry, I have
suggested, describes a certain existing mechanism, which exists as
really as the physical structure described by an anatomist. The
industrial organism has, of course, many properties of which the
economist, as such, does not take account. The labourer has affections,
and imaginations, and opinions outside of his occupation as labourer;
he belongs to a state, a church, a family, and so forth, which affect
his whole life, including his industrial life. Is it therefore
impossible to consider the industrial organisation separately? Not more
impossible, I should reply, than to apply the same method in regard to
the individual body. Were I to regard my stomach simply as a bag into
which I put my food, I should learn very little about the process of
digestion. Still, it is such a bag, and it is important to know where
it is, and what are its purely mechanical relations to other parts of
the body. My arms and legs are levers, and I can calculate the pressure
necessary to support a weight on the hand, as though my bones and
muscles were made of iron and whipcord. I am a piece of mechanism,
though I am more, and all the principles of simple mechanics apply to
my actions, though they do not, by themselves, suffice to explain the
actions. The discovery of the circulation of the blood explained, as I
understand, my structure as a hydraulic apparatus; and it was of vast
importance, even though it told us nothing directly of the other
processes necessarily involved. In this case, therefore, we have an
instance of the way in which a set of perfectly true propositions may,
so to speak, be imbedded in a larger theory, and may be of the highest
importance, though they are not by themselves sufficient to solve any
concrete problem. We can