istoric problems. We cannot
always find the tie which unites certain ethical ideas to practical
definite conditions. The concrete social psychology of past times often
remains impenetrable to us. Often the commonest things remain for us
unintelligible, for example, the animals considered as unclean, or the
origin for the repugnance at marriage between persons of remote degrees
of relationship. A prudent course of study leads us to conclude that the
motives of many details will remain always concealed. Ignorance,
superstition, singular illusions, symbolisms, these with many others are
causes of that unconscious element, often found in customs, which now
constitutes for us the unknown and the unknowable.

The principal cause of all difficulty is precisely in the tardy
appearance of what we call reason, so that the traces of the proximate
motives of ideas have been lost or have remained enveloped in the ideas
themselves.

On the subject of science we can be much more brief.

For a long time history has been made in an artless fashion. Granted and
admitted that the different sciences have their statements in manuals
and encyclopedias, it seemed sufficient to work out chronologically the
appearance of the different formulas, resolving the total of the
systematic summary into the elements which have successively served to
compose it. The general presupposition was simple enough; underneath
this chronology is the rational conception which develops and
progresses.

This method, if so it could be called, had within itself a certain
disadvantage; it permitted us at best to understand how, one stage of
science being granted, another stage of science may be derived from it
by reason, but it did not permit us to discern by what condition of
facts men were driven to discover science for the first time, that is to
say, to reduce considered experience into a new and definite form. The
question was, then, to find why there is an actual history of science,
to find the origin of the scientific necessity, and what unites in a
genetic fashion that necessity to our necessities in the continuity of
the social _processus_.

The great progress of modern technique, which really constitutes the
intellectual substance of the bourgeois epoch, has worked, among other
miracles, this one also, of revealing to us for the first time the
practical origin of the _scientific attitude_. (We can never forget the
Florentine Academy, which produced thi