The expressions 'focal object' and 'marginal object,' which we owe to
Mr. Lloyd Morgan, require, I think, no further explanation. The
distinction they embody is a very important one, and they are the first
technical terms which I shall ask you to remember.

* * * * *

In the successive mutations of our fields of consciousness, the process
by which one dissolves into another is often very gradual, and all sorts
of inner rearrangements of contents occur. Sometimes the focus remains
but little changed, while the margin alters rapidly. Sometimes the focus
alters, and the margin stays. Sometimes focus and margin change places.
Sometimes, again, abrupt alterations of the whole field occur. There can
seldom be a sharp description. All we know is that, for the most part,
each field has a sort of practical unity for its possessor, and that
from this practical point of view we can class a field with other fields
similar to it, by calling it a state of emotion, of perplexity, of
sensation, of abstract thought, of volition, and the like.

Vague and hazy as such an account of our stream of consciousness may be,
it is at least secure from positive error and free from admixture of
conjecture or hypothesis. An influential school of psychology, seeking
to avoid haziness of outline, has tried to make things appear more exact
and scientific by making the analysis more sharp.

The various fields of consciousness, according to this school, result
from a definite number of perfectly definite elementary mental states,
mechanically associated into a mosaic or chemically combined. According
to some thinkers,--Spencer, for example, or Taine,--these resolve