As I have already observed, the process of full and clear recognition, specific and individual, involves a classing of a number of distinct aspects of the object, such as colour, form, etc.

Accordingly, when in a perfectly calm state of mind we fall into illusion with respect to any object plainly visible, it must be through some accidental resemblance between the object and the other object or class of objects with which we identify it.

In the case of individual identification such illusions are, of course, comparatively rare, since here there are involved so many characteristic differences.

On the other hand, in the case of specific recognition there is ample room for error, especially in those kinds of more subtle recognition to which I have already referred.

To "recognize" a person as a Frenchman or a military man, for example, is often an erroneous process.