hat after this
fashion:

Value 1: factors 1, 3. "The man whom I referred to."
Value 2: factors 1, 3, 4. "The man whom they referred to."
Value 3: factors 1, 2, 3. "Whom are you looking at?"
Value 4: factors 1, 2, 3, 4. "Whom did you see?"

We may venture to surmise that while _whom_ will ultimately disappear
from English speech, locutions of the type _Whom did you see?_ will be
obsolete when phrases like _The man whom I referred to_ are still in
lingering use. It is impossible to be certain, however, for we can never
tell if we have isolated all the determinants of a drift. In our
particular case we have ignored what may well prove to be a controlling
factor in the history of _who_ and _whom_ in the relative sense. This is
the unconscious desire to leave these words to their interrogative
function and to concentrate on _that_ or mere word order as expressions
of the relative (e.g., _The man that I referred to_ or _The man I
referred to_). This drift, which does not directly concern the use of
_whom_ as such (merely of _whom_ as a form of _who_), may have made the
relative _who_ obsolete before the other factors affecting relative
_whom_ have run their course. A consideration like this is instructive
because it indicates that knowledge of the general drift of a language
is insufficient to enable us to see clearly what the drift is heading
for. We need to know something of the relative potencies and speeds of
the components of the drift.

It is hardly necessary to say that the particular drifts involved in the
use of _whom_ are of interest to us not for their own sake but as
symptoms of larger tendencies at work in the language. At least three
drifts of major importance are discernible. Each of these has operated
for centuries, each is at work in other parts of our linguistic
mechanism, each is almost certain to continue for centuries, possibly
millennia. The first is the familiar tendency to level the distinction
between the subjective and the objective, itself but a late chapter in
the steady reduction of the old Indo-European system of syntactic cases.
This system, which is at present best preserved in Lithuanian,[139] was
already considerably reduced in the old Germanic language of which
English, Dutch, German, Danish, and Swedish are modern dialectic forms.
The seven Indo-European cases (nominative genitive, dative, accusative,
ablative, locative, instrumental) had been already reduced to four
(nominative genitiv