ty inventory of experience, committed itself to a
premature classification that allowed of no revision, and saddled the
inheritors of its language with a science that they no longer quite
believed in nor had the strength to overthrow. Dogma, rigidly prescribed
by tradition, stiffens into formalism. Linguistic categories make up a
system of surviving dogma--dogma of the unconscious. They are often but
half real as concepts; their life tends ever to languish away into form
for form's sake.

[Footnote 63: Hence, "the square root of 4 _is_ 2," precisely as "my
uncle _is_ here now." There are many "primitive" languages that are more
philosophical and distinguish between a true "present" and a "customary"
or "general" tense.]

There is still a third cause for the rise of this non-significant form,
or rather of non-significant differences of form. This is the mechanical
operation of phonetic processes, which may bring about formal
distinctions that have not and never had a corresponding functional
distinction. Much of the irregularity and general formal complexity of
our declensional and conjugational systems is due to this process. The
plural of _hat_ is _hats_, the plural of _self_ is _selves_. In the
former case we have a true _-s_ symbolizing plurality, in the latter a
_z_-sound coupled with a change in the radical element of the word of
_f_ to _v_. Here we have not a falling together of forms that
originally stood for fairly distinct concepts--as we saw was presumably
the case with such parallel forms as _drove_ and _worked_--but a merely
mechanical manifolding of the same formal element without a
corresponding growth of a new concept. This type of form development,
therefore, while of the greatest interest for the general history of
language, does not directly concern us now in our effort to understand
the nature of grammatical concepts and their tendency to degenerate into
purely formal counters.

We may now conveniently revise our first classification of concepts as
expressed in language and suggest the following scheme:

I. _Basic (Concrete) Concepts_ (such as objects, actions, qualities):
normally expressed by independent words or radical elements; involve
no relation as such[64]

II. _Derivational Concepts_ (less concrete, as a rule, than I, more so
than III): normally expressed by affixing non-radical elements to
radical elements or by inner modification of these; differ from type
I in