In thus instantly recognizing him as a Hindoo, we must, it is plain, attend to the points of similarity, and overlook for the instant the points of dissimilarity.

In the case of individual identification, the same thing happens.

Strictly speaking, no object ever appears exactly the same to us on two occasions.

Apart from changes in the object itself, especially in the case of living beings, there are varying effects of illumination, of position in relation to the eye, of distance, and so on, which very distinctly affect the visual impression at different times.

Yet the fact of our instantly recognizing a familiar object in spite of these fluctuations of appearance, proves that we are able to overlook a very considerable amount of diversity when a certain amount of likeness is present.
It is further to be observed that in these last stages of perception we approach the boundary line between perception and inference.