Define "You"

I've been working in a lab that is interested in deixis, among other things. Deixis is, essentially, context-dependent linguistic reference. So any word that would be entirely ambiguous out of context, like 'now', 'then', 'this', 'that', 'it', 'there', 'me' and 'you' are all deictics.

These words (or rather, how people use these words) are interesting because

a) the speaker must take a personal perspective to use them (if you are 'there', I must be 'here'), and
b) they are used to talk about people, places, and things (both present and absent, concrete and abstract) in terms of how the speaker conceives of them,
c) they are unintelligible to non-humans (though several animal species, notably chimps, are capable of recognizing themselves, abstract symbolic reference is out of their reach), as illustrated below.

PS - Thanks for the cartoon, Dr. Creel!