und in the lower. The differences between
no two terms in the series can be total, nor can any two terms be
identical, as each higher species will embrace all the attributes of the
lower, differing only by the addition of others. This is simply the
physical expression of the logical truth that whatever can be predicated
of the genus can be predicated of every individual contained under it.
As the individual is only the expansion of the genus, so higher physical
types must also be similar expansions of lower.

Here, then, is evolution, or development: primarily an evolution of the
generic into the individual, the continued differentiation of a generic
idea through successive individualizations, each adding to the previous
group of attributes, thus rendering the idea increasingly complex; and,
secondly, an apparent physical evolution or development, interpreting
this logical process by a series of physical forms so related as to
reveal the relation existing between the thoughts thus interpreted. In
the physical representation of the ideas so related, there must be an
apparent physical evolution--that is, the process of evolution logically
must, like the ideas thus evolved, have a physical expression, and the
successive steps in this logical evolution must be revealed by material
forms bearing an analogous relation, and thereby expressing the logical
process. Matter is nothing, so far as we are now concerned, but the
condition necessary to the objective expression of thought. Every phase
of matter is simply an objective formulation of a corresponding phase of
thought. Every addition to form implies an antecedent increase of
thought, as there can be no formal expression until there is something
to be expressed. There can, then, be no such thing as mere material
evolution, for whatever is material is only symbolical.

Matter being thus wholly inert, the origin of the impulse towards
greater complexity must be sought for outside of that which undergoes
the change. The movement by which one species becomes a higher is not an
elaboration, an extension or a differentiation of existing attributes,
but involves the positive addition of a new attribute, different and
distinct from any or all previously existing. One species cannot pass
into another by an innate impulse, for a species is an entity composed
of a determinate number of attributes, and all attributes potentially
present must be considered as actually present. We cannot