appear together. The "comparative method" has assumed several different
forms. Sometimes the subject of study has been a detail of social life
(a usage, an institution, a belief, a rule), defined in abstract terms;
its evolutions in different societies have been compared with a view to
determine the common evolution which is to be attributed to one and the
same general cause. Thus have arisen comparative philology, mythology,
and law. It has been proposed (in England) to give precision to the
comparative method by applying "statistics"; this would mean the
systematic comparison of all known societies and the enumeration of all
the cases where two usages are found together. This is the principle of
Bacon's tables of agreement; it is to be feared that it will be no more
fertile in results. The defect of all such methods is that they apply to
abstract and partly arbitrary notions, sometimes merely to verbal
resemblances, and do not rest on a knowledge of the whole of the
conditions under which the facts occur.

We can conceive a more concrete method which, instead of comparing
fragments, should compare wholes, that is entire societies, either the
same society at different stages of its evolution (England in the
sixteenth, and again in the nineteenth century), or else the general
evolution of several societies, contemporary with each other (England
and France), or existing at different epochs (Rome and England). Such a
method might be useful negatively, for the purpose of ascertaining that
a given fact is not the necessary effect of another, since they are not
always found together (for example, the emancipation of women and
Christianity). But positive results are hardly to be expected of it, for
the concomitance of two facts in several series does not show whether
one is the cause of the other, or whether both are joint effects of a
single cause.

The methodical investigation of the causes of a fact requires an
analysis of the conditions under which the fact occurs, performed so as
to isolate the necessary condition which is its cause; it presupposes,
therefore, the complete knowledge of these conditions. But this is
precisely what we never have in history. We must therefore renounce the
idea of arriving at causes by direct methods such as are used in the
other sciences.

As a matter of fact, however, historians often do employ the notion of
cause, which, as we have shown above, is indispensable for the purpose
of for