ing, however, from the physical inventions to the new moral
ideas and mental contacts, I must interpolate a comment to save myself
from misunderstanding. Generally, those who trace to mechanical
utilities new epochs in the development of mankind proceed upon the
materialistic theory of history. But this theory I have in no wise
committed myself to, for I count it to be false. It is true that I have
traced all the great steps in human advancement to physical inventions,
but I have in no word implied that the inventions themselves were
caused by anything material whatsoever. And if they themselves were, as
I believe, the result of man's mental and spiritual activities reacting
against events, then my tracing of human advancement to them implies no
belief in the materialistic theory of history. Every effect of the
inventions must be set down ultimately not to them, but to their
causes; and their causes were mental. Casually I have said as much, in
remarking several times that they took place by a happy chance, or by a
stroke of insight on the part of some rare genius, or by the reaction
of some mediocre person's intelligent volition against some
extraordinary experience which made the idea of the invention so
obtrusively evident that even a mind not unusually gifted could
scarcely have avoided lighting upon it.

The only phrase I have used by which I cannot absolutely stand is the
expression "by a happy chance"; for I believe that the mental
productions of each person are due not to uncaused chance, or to
accident, but to trends of the social mind that have been set in motion
by mental exigencies arising out of current events. As primitive
peoples, however, have left no record of their mental sequences, we
cannot say with confidence what were the exact experiences that led to
the idea of using fire, or to any other device that transformed the
relation of human beings to one another or to their material habitat. I
only repeat that whatever caused the inventions caused all the remote
effects of these, and that if the causes of the inventions were mental
and spiritual, then an interpretation of history is not materialistic
merely because it traces advancement to mechanical utilities. That I am
right in tracing these to mental and spiritual causes is proved at
least in the case of recent inventions. For we know that their causes
were psychic; we know the mental atmosphere, and how it arose, that
brought forth the telephone and