The content of a belief may consist of words only, or of images only, or
of a mixture of the two, or of either or both together with one or more
sensations. It must contain at least one constituent which is a word
or an image, and it may or may not contain one or more sensations as
constituents. Some examples will make these various possibilities clear.

We may take first recognition, in either of the forms "this is of
such-and-such a kind" or "this has occurred before." In either case,
present sensation is a constituent. For example, you hear a noise, and
you say to yourself "tram." Here the noise and the word "tram" are both
constituents of your belief; there is also a relation between them,
expressed by "is" in the proposition "that is a tram." As soon as your
act of recognition is completed by the occurrence of the word "tram,"
your actions are affected: you hurry if you want the tram, or cease to
hurry if you want a bus. In this case the content of your belief is a
sensation (the noise) and a word ("tram") related in a way which may be
called predication.

The same noise may bring into your mind the visual image of a tram,
instead of the word "tram." In this case your belief consists of a
sensation and an image suitable related. Beliefs of this class are what
are called "judgments of perception." As we saw in Lecture VIII, the
images associated with a sensation often come with such spontaneity
and force that the unsophisticated do not distinguish them from the
sensation; it is only the psychologist or the skilled observer who is
aware of the large mnemic element that is added to sensation to make
perception. It may be objected that what is added consists merely of
images without belief. This is no doubt sometimes the case, but
is certainly sometimes not the case. That belief always occurs in
perception as opposed to sensation it is not necessary for us to
maintain; it is enough for our purposes to note that it sometimes
occurs, and that when it does, the content of our belief consists of a
sensation and an image suitably related.

In a PURE memory-belief only images occur. But a mixture of words
and images is very common in memory. You have an image of the past
occurrence, and you say to yourself: "Yes, that's how it was." Here the
image and the words together make up the content of the belief. And
when the remembering of an incident has become a habit, it may be purely
verbal, and the memory-belief may consist