or the Categories of Physics_ (in the _Zeitschrift fuer
spekulative Physik_) 1800. In the above exposition, however, the modified
philosophy of nature of the second period has also been taken into
account.]

General _matter_ or the filling of space, arises from the co-operation of
three forces: the centrifugal, which manifests itself as repulsion (first
dimension), the centripetal, manifested as attraction (second dimension),
and the synthesis of the two, manifested as gravity (third dimension).
These forces are raised by light to a higher potency, and then make their
appearance as the causes of the _dynamical_ process or of the specific
differences of matter. The linear function of magnetism is the condition
of coherence; the surface force of electricity, the basis of the qualities
perceivable by sense; the tri-dimensional force of the chemical process, in
which the two former are united, produces the chemical qualities. Galvanism
forms the transition to living nature, in which through the operation of
the "copula" these three dynamical categories are raised to _organic_
categories. To magnetism as the most general, and hence the lowest force,
corresponds reproduction (the formative impulse, as nutrition, growth, and
production, including the artistic impulse); electricity develops into
irritability or excitability; the higher analogue to the chemical process
as the most individual and highest stage is sensibility or the capacity
of feeling. (Such at least is Schelling's doctrine after Steffens had
convinced him of the higher dignity of that which is individual, whereas
at first he had made sensibility parallel with magnetism, and reproduction
with chemism, because the former two appear most seldom, and the latter
most frequently. Electricity and irritability always maintained their
intermediate position.) With the awakening of feeling nature has attained
its goal--intelligence. As inorganic substances are distinguished only by
relative degrees of repulsion and attraction, so the differentiation of
organisms is conditioned by the relation of the three vital functions: in
the lower forms reproduction predominates, then irritability gradually
increases, while in the highest forms both of these are subordinated to
sensibility. All species, however, are connected by a common life, all the
stages are but arrests of the same fundamental force. This accentuation
of the unity of nature, which establishes a certain kinship betwee