h causes only as are themselves phenomena.
The fact that our knowledge is limited to the succession and coexistence of
phenomena is not to be lamented as a defect: the only knowledge which is
attainable by us is at the same time the only useful knowledge, that which
lends us practical power over phenomena. When we inquire into causes we
desire to hasten or hinder the effect, or to change it as we wish, or at
least to anticipate it in order to make our preparations accordingly. Such
foresight and control of events can be attained only through a knowledge
of their laws, their order of succession, their phenomenal causes. _Savoir
pour prevoir_. But, although the prevision of facts is the only knowledge
which we need, men have always sought after another, an "absolute"
knowledge, or have even believed that they were in possession of it; the
forerunners of the positive philosophy themselves, Bacon and Descartes,
have been entangled in this prejudice. A long intellectual development was
required to reach the truth, that our knowledge does not extend beyond
the cognition of the succession and coexistence of facts; that the same
procedure must be extended to abstract speculation which the common mind
itself makes use of in its single actions. On the other hand, the positive
philosophy, notwithstanding its rejection of metaphysics, is far from
giving its sanction to empiricism. Every isolated, empirical observation
is useless and uncertain; it obtains value and usefulness only when it is
defined and explained by a theory, and combined with other observations
into a law--this makes the difference between the observations of the
scholar and the layman.

The positive stage of a science, which begins when we learn to explain
phenomena by their laws, is preceded by two others: a theological stage,
which ascribes phenomena to supposed personal powers, and a metaphysical
stage, which ascribes them to abstract natural forces. These three periods
denote the childhood, the youth, and the manhood of science.

The earliest view of the world is the theological view, which derives the
events of the world from the voluntary acts of supernatural intelligent
beings. The crude view of nature sees in each individual thing a being
animated like man; later man accustoms himself to think of a whole class
of objects as governed by one invisible being, by a divinity; finally
the multitude of divinities gives place to a single God, who creates,
maintain