a background, a near and a
remote, a center and a margin or periphery. The contents of
consciousness are vivid or clear in the center of this field and fade
away into vagueness or obscureness in proportion to their approach to
the periphery. Or, to take the other comparison, the focus may be
represented by the crest of a wave and the margin by what we may call
its base. This illustration has the advantage that it indicates the
difference between higher and lower degrees of concentration. As
concentration increases, the crest of the wave rises higher and its
width decreases, while the reverse is true where the concentration of
attention is less intense. All consciousness possesses the distinction
of focus and margin in some degree; however much we may be absorbed in
an object or topic, there is always an indirect mental vision that
informs us of other facts, which for the time being are in the
background of our consciousness.

For purposes of description a metaphor is at best a clumsy device. It
has a tendency to substitute itself for the thing to be described and
thus to conceal its limitations and inaccuracies. The present case is no
exception. I am forced to think that the visual field in particular is a
thoroughly vicious metaphor when employed to body forth the distinction
of focus and margin. Whatever this distinction may in the end turn out
to be, it is not such as this comparison would lead one to suppose.
Objects seen in indirect vision appear obscure and blurred precisely
because they are in the focus of consciousness. We get pretty much the
same sort of obscureness or blur on a printed page when we look at it in
indirect vision as we do when we look at it from a distance that is just
too great to make out the words or characters. What the illustration
shows is that things look different according as the circumstances under
which we see them are different, but what bearing this has on marginal
consciousness is not at all obvious to an unsophisticated intelligence.

When we speak of a focus and margin in consciousness, we are presumably
dealing with conscious fact. Now this illustration of the visual field
does not represent conscious fact. Ordinary perception carries with it
no sense of obscureness at all, and when it does we have exactly the
same kind of situation as when an object is too distant or in some other
way inaccessible to satisfactory perception. That is, the object
perceived is in the 'focus' and