The meaning of the word philoi is deeply rooted in the concept of reciprocity; encompassing the exchange of favors and support, in addition to a profound sense of duty to each other.
Further, there was great pride associated with not only helping philoi but also in harming one's echthroi, and the importance of fulfilling these two duties to upload an overarching, strict friend-enemy dichotomy is manifested in a variety of other aspects in Greek life, including literature, theatre and in court.
"[8] With the exception of festivals, women had limited roles outside of the home and therefore had finite opportunities to cultivate reciprocal relationships with their philoi and echthroi in the same way men in Greece did.
[10] The prevalence of warfare in which heroes compete against each other to prove their superiority evidences this dichotomy; that there must be two explicit opposing sides, and both parties must act in accordance to their duty to harm one another, typically in a public display.
In Nicomachean Ethics, Aristotle writes that "to be friends, then, they must be mutually recognized as bearing goodwill and wishing well to each other,"[12] indicating that a philoi is characterized by not necessarily fondness for someone, but a concern for one another that is assuredly reciprocated.
Aristotle writes that "friendship is likened to one's love for oneself"[13] but that philoi nonetheless exist "for the sake of some use to be made of him,"[14] so they appear to serve both self-serving and altruistic intentions.