argument, that trespass was extended so as to embrace harms which
were foreseen, but which were not the intended consequence of the
defendant's act. /2/ Thence again it extended to unforeseen
injuries. /3/

It will be seen that this order of development is not quite
consistent with an opinion which has been held, that it was a
characteristic of early law not to penetrate beyond the external
visible fact, the damnum corpore corpori datum. It has been
thought that an inquiry into the internal condition of the
defendant, his culpability or innocence, implies a refinement of
juridical conception equally foreign to Rome before the Lex
Aquilia, and to England when trespass took its shape. I do not
know any very satisfactory evidence that a man was generally held
liable either in Rome /4/ or England for the accidental
consequences even of his own act. But whatever may have been the
early law, the foregoing account shows the starting-point of the
system with which we have to deal. Our system of private
liability for the consequences of a man's own acts, that is, for
his trespasses, started from the notion of actual intent and
actual personal culpability.

The original principles of liability for harm inflicted by [5]
another person or thing have been less carefully considered
hitherto than those which governed trespass, and I shall
therefore devote the rest of this Lecture to discussing them. I
shall try to show that this liability also had its root in the
passion of revenge, and to point out the changes by which it
reached its present form. But I shall not confine myself strictly
to what is needful for that purpose, because it is not only most