Prosopagnosia.

"And what is the nature of this knowledge or recollection? I mean to ask, Whether a person, who having seen or heard or in any way perceived anything, knows not only that, but has a conception of something else which is the subject, not of the same but of some other kind of knowledge, may not be fairly said to recollect that of which he has the conception?""And when the recollection is derived from like things, then another consideration is sure to arise, which is, Whether the likeness in any degree falls short or not of that which is recollected?" "The Philosophy of Plato" Phaedo (the Jowett translation).