rules to human conduct has always been illusory.

IV

Liability

A systematist who would fit the living body of the law to his logical
analytical scheme must proceed after the manner of Procrustes. Indeed,
this is true of all science. In life phenomena are unique. The
biologist of today sometimes doubts whether there are species and
disclaims higher groups as more than conveniences of study. "Dividing
lines," said a great American naturalist, "do not occur in nature
except as accidents." Organization and system are logical
constructions of the expounder rather than in the external world
expounded. They are the means whereby we make our experience of that
world intelligible and available. It is with no illusion, therefore,
that I am leading you to a juristic _ultima Thule_ that I essay a bit
of systematic legal science on a philosophical basis. Even if it
never attains a final system in which the law shall stand fast
forever, the continual juristic search for the more inclusive order,
the continual juristic struggle for a simpler system that will better
order and better reconcile the phenomena of the actual administration
of justice, is no vain quest. Attempts to understand and to expound
legal phenomena lead to generalizations which profoundly affect those
phenomena, and criticism of those generalizations, in the light of the
phenomena they seek to explain and to which they give rise, enables us
to replace them or modify them or supplement them and thus to keep the
law a growing instrument for achieving expanding human desires.

One of the stock questions of the science of law is the nature and
system and philosophical basis of situations in which one may exact
from another that he "give or do or furnish something" (to use the
Roman formula) for the advantage of the former. The classical Roman
lawyer, thinking in terms of natural law, spoke of a bond or relation
of right and law between them whereby the one might justly and
legally exact and the other was bound in justice and law to perform.
In modern times, thinking, whether he knows it or not, in terms of
natural rights and by derivation of legal rights, the analytical
jurist speaks of rights _in personam_. The Anglo-American lawyer,
thinking in terms of procedure, speaks of contracts and torts, using
the former term in a wide sense. If pressed, he may refer certain
enforceable claims to exact and duties of answering to the exaction to
a Romanist categor