suffice to give
an entirely new turn to the course of events. If every other antecedent
of the first French Revolution were again present, still there might be
no second revolution, provided only that, instead of another Louis the
Sixteenth, a Leopold of Belgium, or a Frederick the Great were king.[28]
With the last mentioned on the throne, there would assuredly be no
repetition of that vacillation of purpose which rocked the cradle and
fostered the growth of popular fury till it culminated in a Reign of
Terror. Since, then, there cannot be either a repetition of the same
circumstances to act upon men, or a reproduction of the same sort of
men to be acted upon by circumstances, human conduct can never exhibit a
repetition of the same phenomena; experience of the past can never, in
social or political affairs, furnish a formula for predictions as to the
future. Accordingly Mr. Mill, in common with Mr. Stephen, disclaims the
idea of positive, and pleads only for conditional, predictions. But the
very term 'conditional predictions' involves a contradiction, since it
is obviously impossible to see beforehand what perhaps may never come to
pass. What is meant by the phrase is really nothing more than
conjectures; and conjectures, however ingenious and reasonable, cannot
be admitted within the pale of science. They cannot be accepted as
fruits of a tree which has by the quality of its fruits proved its right
to be entitled the Science of History.

With the view of enhancing the value of conditional predictions, it has
been urged that they are of precisely the same description as those
which we are in the habit of hazarding with respect to our familiar
acquaintance. There are, it is said, 'general maxims regarding human
conduct, by the application of which to given states of fact,
predictions may be made as to what will happen;' and all that is
necessary for the construction of historical science, is the employment
of these maxims on a larger scale. If the premiss here be sound, the
inference may be owned to be sufficiently legitimate. If there be any
formula with which the actions of individuals are observed to
correspond, there is every likelihood that the same formula may, by
extension and amplification, be adapted to the actions of communities.
But, although there are plenty of maxims telling men what they _ought_
to do, there is not one--except that which declares that they must all
die--which affords any positive informa