today, had its birth and
development as the science of bourgeois production, after being puffed
up with the illusion of representing the absolute laws of all forms of
production, has through the dear school of experience entered since, as
everyone knows, upon a period of self-criticism. Just as this
self-criticism gave birth, on one side, to critical communism, so on the
other side it has given birth, through the labor of the calmest, the
wisest and the most prudent of the academic tradition, to the
_historical school of economic phenomena_. Thanks to this school, and
through the effect of the application of the descriptive and comparative
methods, we are henceforth in possession of a vast sum of knowledge on
the different historical forms of _economics_, from the most complex
facts and those best specified through essential differences of types,
down to the special domain of a cloister or a trade guild of the Middle
Ages. The same thing has taken place with _statistics_, which, by the
indefinite combination of its sources, succeeds now in throwing light,
with a sufficient approximation, upon the movement of population in past
centuries.

These studies, certainly, are not made in the interest of our doctrine,
and oftener than not they are made in a spirit hostile to socialism;
something not observed, we may say in passing, by those foolish readers
of printed papers who so often confuse _economic history_, _historical
economics_, and _historical materialism_. But these studies, apart from
the materials which they gather, are remarkable in that they witness the
progress which is in course of making the _internal history_ which,
little by little, is taking the place of the _external history_ with
which, for centuries, the men of letters and artists were occupied.

A good part of these materials that have been gathered must always be
submitted to new corrections, as for that matter happens in every domain
of empirical knowledge, which oscillates continually between what is
held for certain and what is simply probable, and what must, later, be
integrated or eliminated.

The deductions and the combinations of the historians of economics, or
of those who relate history in general, availing themselves of the
guiding thread of economic phenomena, are not always so plausible or so
conclusive, that one does not feel the need of saying to them: All this
must be taken back and worked over. But that which is undoubted is the
fact