What will be pronounced strange or curious is largely determined by
the range and composition of the common body of knowledge to whose
laws and uniformities the phenomena in question apparently fail to
conform. What is passing strange to one generation may become easily
intelligible to the next. We all have eyes that see not for all but
a limited range of facts and views; and we unconsciously fill out
the blind-spots of our mental retinæ according to the habits and
acquisitions of the surrounding areas. We observe and record what
interests us; and this interest is in turn the outcome of a greater
or lesser endowment, knowledge, and training. A new observation
requires, as a rule, not a new sense-organ or an additional faculty,
nor even more powerful or novel apparatus, but an insight into
the significance of quite lowly and frequent things. Most of the
appearances of the earth's crust, which the modern geologist so
intelligently describes, were just as patent centuries ago as now;
what we have added is the body of knowledge that makes men look for
such facts and gives them a meaning. And although "the heir of all
the ages," we can hardly presume to have investigated more than a
modest portion of our potential inheritance; future generations
will doubtless acquire interests and points of view which will
enable them to fill some of the many gaps in our knowledge, to find
a meaning in what we perchance ignore or regard as trivial, and to
reduce to order and consistency what to us seems strange or curious
or unintelligible. And future generations, by virtue of a broader
perspective and a deeper insight, may give little heed to what we
look upon as significant,--much as we pronounce irrelevant and
superstitious the minute observances whereby primitive folk strive to
attract the good fortunes and to avoid the dangers of human existence.
I
The possibility of the transference of thought, apart from the
recognized channels of sensation, has been too frequently discussed,
with the suppressed or unconscious assumption that our knowledge
of the means whereby we ordinarily and normally, consciously and
unconsciously, convey to others some notion of what is passing in our
own minds, is comprehensive and exhaustive. Nothing could be farther
from the truth. Whenever a mode of perception, no matter how limited
or apparently trivial, has been thoroughly investigated, there have
been discovered, or at least suggested, unrecognized possibilities
of its use and development. And no result of experimental inquiry is
more constantly illustrated than the extent to which inferences from
sensations and the exercise of faculties may proceed without arousing
consciousness of their existence. Many color-blind persons remain
quite ignorant of their defect; and it was only after the description
of his own notable deficiencies by Dalton (in 1794) that the general
prevalence of color-blindness became recognized. The fact that a
portion of every one's retina is as blind as his finger-tip escaped
observation until about two centuries ago; and this because the
normal use of our eyes does not present the conditions of its easy
detection; and for a like reason we persistently refuse to see the
double images that are constantly formed upon our retinæ. With the
same unconsciousness that we receive sensations and draw inferences
from them, do we give to others indications of what is going on in
our minds, and read between their words and under their expressions
what "half reveals and half conceals the thoughts that lie within."
It is important to emphasize the serious limitations as yet attaching
to our knowledge of the detailed possibilities of normal perception
and inference, in order to realize the corresponding hesitancy with
which we should regard any series of facts, no matter how apparently
inexplicable, as evidence of a supernormal kind of mental telegraphy.
A further principle important in this connection, and one which is
likewise borne out by experimental inquiry, is the general similarity
in our mental machinery in matters great and small, and the resulting
frequency with which similar trains of thought may be carried on
by different persons as the outcome of similar but independent
brain-functioning. There is a natural tendency to exaggerate the
individuality of our own ways of thought and expression; and yet but
little reflection is necessary to suggest how easily this fond belief
may be at least partially delusive. In certain lines of thought,
such as mathematics, we should regard it as strange if two thinkers,
starting with the premises determined by the problem in hand, should
not reach the same conclusion; in others, such as economic or
political questions, we observe the preponderance of evidence in one
direction, and yet can appreciate the grounds of a contrary opinion;
and while in still other cases we regard the verdict as a matter of
taste or of individual preference, it may be questioned whether this
is so unmotived or lawless a process as is commonly assumed. While
we properly expect more mental community in certain lines than in
others, we have good grounds for believing that it exists everywhere
and only awaits the proper modes of investigation to reveal it in
its full extent and significance. With the marvelously increased
facilities for the dissemination and transportation of thought, the
range of such mental community is certain to be correspondingly
extended. Coincidences arising from the bringing together of widely
separated and apparently unrelated happenings are sure to multiply,
when the means of bringing them together are so vastly increased.
Each man's world is enlarged by the enlargement of the whole. It
becomes possible for him to come into relation with infinitely more
persons and events, and the resulting coincidences are nowadays more
likely to be noticed and recorded.
If we consider the logical ease with which the successful solution of
one portion of a problem suggests the next step; how imperceptibly
and yet effectively sentiments and points of view and the spirit
of the time are disseminated; how many persons there are in this
busily reflective era occupied with similar thoughts and schemes,
and how readily they may come into communication; how many are
anxiously studying the popular taste and demand to determine what
literary venture or mechanical invention is likely to be timely and
successful; how the possession of a common inheritance, patriotic
interests, education, literature, political arena, social usages,
newspaper intelligence, household conveniences, and the endless
everyday factors of our complex, richly detailed existence all
contribute to our common life,--shall we wonder that some two
or half a dozen intellects should give expression to similar
thoughts at nearly the same time? Would it not be infinitely more
wonderful if such coincidences did not constantly occur? In the more
original contributions to literature, science, and inventions, such
thought-correspondences should be rarer; and certainly this is true.
Contrast the number of striking similarities in the higher walks of
literature and science with those that occur in small inventions.
Hardly a day passes without the coincidence of two persons thinking
of devices for accomplishing the same purposes, so essentially
similar that patents could not be given to both. It is certainly not
difficult to understand why several different patterns of typewriting
machines should be invented nearly simultaneously, and it would
not be altogether mysterious if, at the first, two inventors had
independently reached the idea of a writing-machine at nearly the
same time. The experience of offering an article to an editor and
receiving a reply to the effect that another article dealing with a
similar topic in a similar way was already awaiting the compositor
is not unusual. It is true that these coincidences are of a minor
order, but it seems desirable to emphasize the frequency of these
minor forms in order to suggest the law-abiding character of the
rarer or the more striking forms; for this is just what the normal
distribution of such phenomena would lead us to expect.
It would be pleasant to believe that the application of the doctrine
of chances to problems of this character is quite generally
recognized; but this recognition is so often accompanied by the
feeling that the law very clearly applies to all cases but the
one that happens to be under discussion, that I fear the belief
is unwarranted. Moreover, the notion seems to prevail that these
coincidences should occur with equal frequency to all persons;
while, in fact, the law of probability provides for the most various
distribution among individuals. However, the attempt, and it may be
the sincere attempt, to apply proper conceptions of probability and
improbability to such problems often fails, because of an unfortunate
mental attitude which presents, with an outward acquiescence in
the objective view of the problem, an inward conviction in which
the subjective interpretation is really dominant; for this and
other reasons, this objective method of viewing the matter, however
pertinent, is not the most important.