sted. To deny this principle is to deny the necessity of continuity
in reasoning. This continuity of thought is represented in matter by the
persistence of generic forms under specific differences. But just as the
specific is the generic with certain additions, so the individual is
this same generic with still further additions; and these additions,
whether considered solely in space, as given in the symbols of physical
science, or in time as in the conceptions of intellectual science, must
be determined by the same unvarying law. The persistence of the same
form furnishes us the means of identifying this relation, while the
differences reveal to us the successive steps by which the generic was
differentiated into the individual.

If the creative thought has been expressed by the forms of matter, the
laws of thought must be thus expressed in the relative forms of matter.
Anything less than this, while it might interpret isolated ideas, would
not communicate the method of the creative process, and science is
nothing but the discovery of this method. If the terms of the logical
process must be arranged in a series, the physical symbols rendering
this logical process cognizable, must be arranged in a similar series,
for science becomes impossible when the logical process becomes
undiscoverable.

The differences between the terms in this series must be cognizable. Two
terms which are indistinguishable are practically identical; and two
terms which are not identical vary by a difference which is cognizable
by itself apart from either term. The steps in the logical evolution of
the final term. _Being_ must be separable to be cognizable, and the
material forms interpreting these steps to the senses must also be
distinguishable. A species differs from the genus by the addition of at
least one attribute. Now, if the species is distinguishable from the
genus, the attribute which differentiates it, must be separately
cognizable--so also the individual differs from the species by the
addition of attributes, which must in like manner be separately
cognizable, or the species will never be conceived independently of the
individuals. A thought cannot proceed by insensible steps, nor can its
material expression vary otherwise than by determinate and
distinguishable differences. The distinction of species is thus a
logical necessity. The addition of distinct attributes to the genus
gives origin to distinct species; variation in attribut