ch is independent of images, by means of which
we can criticize image-memories. But I do not think such an inference is
warranted.

What results, formally, from our knowledge of the past through images
of which we recognize the inaccuracy, is that such images must have two
characteristics by which we can arrange them in two series, of which one
corresponds to the more or less remote period in the past to which
they refer, and the other to our greater or less confidence in their
accuracy. We will take the second of these points first.

Our confidence or lack of confidence in the accuracy of a memory-image
must, in fundamental cases, be based upon a characteristic of the image
itself, since we cannot evoke the past bodily and compare it with the
present image. It might be suggested that vagueness is the required
characteristic, but I do not think this is the case. We sometimes
have images that are by no means peculiarly vague, which yet we do not
trust--for example, under the influence of fatigue we may see a friend's
face vividly and clearly, but horribly distorted. In such a case we
distrust our image in spite of its being unusually clear. I think
the characteristic by which we distinguish the images we trust is the
feeling of FAMILIARITY that accompanies them. Some images, like some
sensations, feel very familiar, while others feel strange. Familiarity
is a feeling capable of degrees. In an image of a well-known face,
for example, some parts may feel more familiar than others; when this
happens, we have more belief in the accuracy of the familiar parts than
in that of the unfamiliar parts. I think it is by this means that we
become critical of images, not by some imageless memory with which
we compare them. I shall return to the consideration of familiarity
shortly.

I come now to the other characteristic which memory-images must have
in order to account for our knowledge of the past. They must have some
characteristic which makes us regard them as referring to more or less
remote portions of the past. That is to say if we suppose that A is the
event remembered, B the remembering, and t the interval of time between
A and B, there must be some characteristic of B which is capable of
degrees, and which, in accurately dated memories, varies as t varies.
It may increase as t increases, or diminish as t increases. The question
which of these occurs is not of any importance for the theoretic
serviceability of the characte