t.
Even where this modification takes the direction of increasing
complexity it does not necessarily constitute betterment; and it is
entirely consistent with the principle of adaptation that it should
take the reverse direction. Biological evolution signifies only a
steady yielding to the pressure of the physical environment, whether
for better or for worse. It is also important not to confuse the
conception of progress with that of mere change or temporal duration.
Because society has grown older it has not necessarily on that account
grown wiser; nor because it has changed much has it necessarily on that
account changed for the better. Whether the accumulations of the past
are wealth or rubbish is not to be determined by their bulk.

Progress cleared of these ambiguities means, then, _a change from good
to better_; an increase, in the course of time, of the value of life,
whatever that may be. Taken in the absolute sense it means, not a gain
here or a gain there, but _a gain on the whole_. It is impossible to
reach any conclusion whatsoever concerning progress except in the light
of some conception of the total enterprise of life. Every advance must
be estimated not merely in relation to the interest immediately {127}
served, but in relation to that whole complex of interests which is
called humanity.

In discussing progress I shall therefore with right employ those moral
conceptions which I have already defined. I shall regard as good
whatever fulfils interests, and as morally good whatever fulfils all
interests affected to the maximum degree. Especial importance now
attaches to the principle which I have phrased the _quantitative basis
of preference_. Since progress involves the change from good to
better, it implies an increment of value. The later age is judged to
be _as good and better_. I can see no way of verifying such a
proposition unless it be possible to find in the greater good both the
lesser good and also something added to it and likewise accounted good.
In other words, progress involves measurement of value, and this
involves some _unit of value_ which is common to the terms compared.
The method must be in the last analysis that of superimposition.

Bagehot virtually employs this method in the chapter of his _Physics
and Politics_, which he entitles "Verifiable Progress Politically
Considered." Let me quote, for example, his comparison of the
Englishman with the primitive Australian.