a zooelogist has completed his description of a bird in the
landscape, he has given account of hundreds of thousands of things; but
before the psychologist would complete the enumeration of the mental
elements which enter into the seeing of the table, he would have to give
account of by far more psychical elements. Every point in the surface of
the table has its own light value, perhaps different in its quality and
intensity and saturation, in its hue and tint and shade from the next
one, and at whatever point of the table's edge our attention is
directed, each one involves numberless shades in the vividness of all
the other points and numberless mental relations of space perception
among the various parts of the table. In the thorough analysis of the
describing psychologist, every single idea, and in the same way, every
single emotion or feeling or judgment becomes complex like a living
organism, an aggregate of thousands of mental tissues, and yet made up
from "the stuff that dreams are made of."

But there is one particular difficulty which makes the psychological
description so much harder than that of the physicist, and which gives
rise to many disagreements and discussions in psychological literature.
The psychologist has not only to tear the complex into pieces and thus
to seek the elements, but he has to fixate those elements for the
purpose of communication, as, of course, a scientific description
demands that he be able to give account to others of what he
experiences. The physicist has no difficulty whatever in that line
because, as we saw, the world of physical things is the world which all
men are sharing together. Every element which I find in it, I can show
to every other person, and if I cannot show that particular thing,
because I cannot yet carry the mountain to another place, then I can at
least measure it, as we share those standards of space. Thus natural
science has in its objective measurements the possibility of describing
every part of the physical world. The psychical world, on the other
hand, is as we saw, the world which is private property. Every effort at
description is thus entirely in vain as long as our mental facts cannot
somehow be linked with physical happenings. If I say that I have in my
mind sweetness or sourness, or bitterness or saltness, I cannot carry
any understanding to anyone else and therefore cannot give any
description until I have agreed that I mean by sweetness the sensa