sion. We must understand
that every technical science says only: you must make use of this
means, if you wish to reach this or that particular end. But no
technical science can decide within its limits whether the end itself
is really a desirable one. The technical specialist knows how he ought
to build a bridge or how he ought to pierce a tunnel, presupposing
that the bridge or the tunnel is desired. But whether they are
desirable or not is a question which does not concern the technical
scientist, but which must be considered from economic or political or
other points, of view. Everywhere the engineer must know how to reach
an end, and must leave it to others to settle whether the end in
itself is desirable. Often the end may be a matter of course for every
reasonable being. The extreme case is presented by the applied science
of medicine, where the physician subordinates all his technique to the
end of curing the patient. Yet if we are consistent we must
acknowledge that all his medical knowledge can prescribe to him only
that he proceed in a certain way if the long life of the patient is
acknowledged as a desirable end. The application of anatomy,
physiology, and pathology may just as well be used for the opposite
end of killing a man. Whether it is wise to work toward long life, or
whether it is better to kill people, is again a problem which lies
outside the sphere of the applied sciences. Ethics or social
philosophy or religion have to solve these preliminary' questions. The
physician as such has only to deal with the means which lead toward
that goal.

We must make the same discrimination in the psychotechnical field. The
psychologist may point out the methods by which an involuntary
confession can be secured from a defendant, but whether it is
justifiable to extort involuntary confessions is a problem which does
not concern the psychologist. The lawyers or the legislators must
decide as to the right or wrong, the legality or illegality, of
forcing a man to show his bidden ideas. If such an end is desirable,
the psychotechnical student can determine the right means, and that is
the limit of his office. We ought to keep in mind that the same holds
true for the application of psychology in economic life. Economic
psychotechnics may serve certain ends of commerce and industry, but
whether these ends are the best ones is not a care with which the
psychologist has to be burdened. For instance, the end may be the
se