erary of a sovereign, the days and the places confirm each other
when they harmonize so as to form a coherent whole. An institution or a
popular usage is established by the harmony of accounts, each of which
is no more than probable, relating to different times and places.

This method is a difficult one to apply. The notion of harmony is a much
vaguer one than that of agreement. We cannot assign any precise general
rules for distinguishing facts which are sufficiently connected to form
a whole, the harmony of whose parts would be conclusive; nor can we
determine beforehand the duration and extent of that which may be taken
to form a whole. Facts separated by half a century of time and a hundred
leagues of space may confirm each other in such a way as to establish a
popular usage (for example, among the ancient Germans); but they would
prove nothing if they were taken from a heterogeneous society subject to
rapid evolution (take, for example, French society in 1750, and again in
1800, in Alsace and in Provence). Here we have to study the relation
between the facts. This brings us to the beginnings of historical
construction; here is the transition from analytical to synthetic
operations.

VII. But it remains to consider cases of discordance between facts
established by documents and other facts established by other methods.
It happens sometimes that a fact obtained as an historical conclusion is
in contradiction with a body of known historical facts, or with the sum
of our knowledge of humanity founded on direct observation, or with a
scientific law established by the regular method of an established
science. In the first two cases the fact is only in conflict with
history, psychology, or sociology, all imperfectly established sciences;
we then simply call the fact _improbable_. If it is in conflict with a
true science it becomes a _miracle_. What are we to do with an
improbable or miraculous fact? Are we to admit it after examination of
the documents, or are we to pass on and shelve the question?

_Improbability_ is not a scientific notion; it varies with the
individual. Each person finds improbable what he is not accustomed to
see: a peasant would think the telephone much more improbable than a
ghost; a king of Siam refused to believe in the existence of ice. It is
important to know who precisely it is to whom the fact appears to be
improbable. Is it to the mass who have no scientific culture? For these,
science i