A friend to all is a friend to none.

We traced this line back through several channels and found the sentiment firmly rooted in Aristotle's treatment of friendship — in the *Nicomachean Ethics* Book IX, chapter 10 (around 1171a15–20), he argues that one cannot be a true friend to many and invokes a Greek proverb to that effect, and Diogenes Laertius preserves a related maxim among Aristotle's sayings ("he who has many friends has no friend"). A standard proverb reference, Apperson's *Dictionary of Proverbs*, lists "A friend to all is a friend to none" and expressly ties it to Diogenes Laertius and Aristotle, quoting the Greek "ᾧ φίλοι οὐδεὶς φίλος." That said, the exact modern English wording does not appear verbatim in any surviving Aristotelian text; it circulates broadly as a general proverb, showing up in German, Spanish, and Italian equivalents in proverb anthologies and in unrelated grammar and conversation books with no attribution at all. We weighed the suggestion that it belongs to Aesop or Chaucer, but found no citable primary text placing this exact line in either author's hand, so there is no stronger competing origin that would displace Aristotle. What we have, then, is a polished proverbial condensation of a genuinely Aristotelian idea whose exact phrasing cannot be pinned to a primary line in his corpus, while credible reference works continue to credit the sentiment to him. Given a documented ancient basis (the proverb Aristotle himself cites and the Diogenes Laertius maxim) but no verbatim source for the modern English sentence, this is best classified as attributed.