very alarming to
young children. In what opposite ways must the child's parents have
apperceived the burning house and the engine respectively!

The self-same person, according to the line of thought he may be in, or
to his emotional mood, will apperceive the same impression quite
differently on different occasions. A medical or engineering expert
retained on one side of a case will not apperceive the facts in the same
way as if the other side had retained him. When people are at
loggerheads about the interpretation of a fact, it usually shows that
they have too few heads of classification to apperceive by; for, as a
general thing, the fact of such a dispute is enough to show that neither
one of their rival interpretations is a perfect fit. Both sides deal
with the matter by approximation, squeezing it under the handiest or
least disturbing conception: whereas it would, nine times out of ten, be
better to enlarge their stock of ideas or invent some altogether new
title for the phenomenon.

Thus, in biology, we used to have interminable discussion as to whether
certain single-celled organisms were animals or vegetables, until
Haeckel introduced the new apperceptive name of Protista, which ended
the disputes. In law courts no _tertium quid_ is recognized between
insanity and sanity. If sane, a man is punished: if insane, acquitted;
and it is seldom hard to find two experts who will take opposite views
of his case. All the while, nature is more subtle than our doctors. Just
as a room is neither dark nor light absolutely, but might be dark for a
watchmaker's uses, and yet light enough to eat in or play in, so a man
may be sane for some purposes and insane for others,--sane enough to be
left at large, yet not sane enough to take care of his financial
affairs. The word 'crank,' which became familiar at the time of
Guiteau's trial, fulfilled the need of a _tertium quid_. The foreign
terms 'desequilibre,' 'hereditary degenerate,' and 'psychopathic'
subject, have arisen in response to the same need.

The whole progress of our sciences goes on by the invention of newly
forged technical names whereby to designate the newly remarked aspects
of phenomena,--phenomena which could only be squeezed with violence into
the pigeonholes of the earlier stock of conceptions. As time goes on,
our vocabulary becomes thus ever more and more voluminous, having to
keep up with the ever-growing multitude of our stock of apperceiving
ideas.

I