Logicians have included this kind of error under what they call "fallacies of observation." Errors of recognition, both specific and individual, are, of course, more easy in the case of distant objects or objects otherwise indistinctly seen.

It is noticeable in these cases that, even when perfectly cool and free from emotional excitement, we tend to interpret such indistinct impressions according to certain favourite types of experience, as the human face and figure.

Our interpretative imagination easily sees traces of the human form in cloud, rock, or tree-stump.
Again, even when there is no error of recognition, in the sense of confusing one object with other objects, there may be partial illusion.
I have remarked that the process of recognizing an object commonly involves an overlooking of points of diversity in the object, or aspect of the object, now present.

And sometimes this inattention to what is actually present includes an error as to the actual visual sensation of the moment.

Thus, for example, when I look at a sheet of white paper in a feebly lit room, I seem to see its whiteness.