Note 9 — Chapter I · THE LOWER FORMS OF ABSTRACTION.

This term is borrowed from the well-known works of Galton on composite photographs, which are scarcely more than twenty years old. Huxley in his book on Hume (Chapter IV.) appears to be the first who introduced it into psychology, as shown by the following passage: “This mental operation may be rendered comprehensible by considering what takes place in the formation of compound photographs—when the images of the faces of six sitters, for example, are each received on the same photographic plate, for a sixth of the time requisite to take one portrait. The final result is that all those points in which the six faces agree are brought out strongly, while all those in which they differ are left vague; and thus what may be termed a generic portrait of the six is produced. Thus our ideas of single complex impressions are incomplete in one way, and those of numerous, more or less similar, complex impressions are incomplete in another way; that is to say, they are generic.... And hence it follows that our ideas of the impressions in question are not, in the strict sense of the word, copies of those impressions; while at the same time they may exist in the mind independently of language.” Romanes employs the word “recept” for “generic images,” as marking their intermediate place between the “percept” which is below, and the “concept” which is above them.