neglected. The German scientists, especially Oken and Goethe, who were
occupied with similar speculations at the same time, seem to have
known nothing about Lamarck's work. If they had known it, they would
have been greatly helped by it, and might have carried the theory of
evolution much farther than they found it possible to do.

To give an idea of the great importance of the Philosophie Zoologique,
I will briefly explain Lamarck's leading thought. He held that there
was no essential difference between living and lifeless beings. Nature
is one united and connected system of phenomena; and the forces which
fashion the lifeless bodies are the only ones at work in the kingdom
of living things. We have, therefore, to use the same method of
investigation and explanation in both provinces. Life is only a
physical phenomenon. All the plants and animals, with man at their
head, are to be explained, in structure and life, by mechanical or
efficient causes, without any appeal to final causes, just as in the
case of minerals and other inorganic bodies. This applies equally to
the origin of the various species. We must not assume any original
creation, or repeated creations (as in Cuvier's theory), to explain
this, but a natural, continuous, and necessary evolution. The whole
evolutionary process has been uninterrupted. All the different kinds
of animals and plants which we see to-day, or that have ever lived,
have descended in a natural way from earlier and different species;
all come from one common stock, or from a few common ancestors. These
remote ancestors must have been quite simple organisms of the lowest
type, arising by spontaneous generation from inorganic matter. The
succeeding species have been constantly modified by adaptation to
their varying environment (especially by use and habit), and have
transmitted their modifications to their successors by heredity.