In the New York Times article "The Vexing Problem of the ‘Medium Friend’" (22 June 2024) Lisa Miller analyzes, thoughtfully and with nuance, the range of "Friendships". It's a longish essay that makes a host of good points along the way. Memorable tidbits:

• "Medium friends are genuine friends. You share history (such as the same alma mater), circumstances (an employer) or interests (rude jokes, the royals, thrifting or squash). Medium friends make you laugh, bring news, offer insights or expertise. But, unlike the closest friends, medium friends test the limits of your time, love and energy. There are only so many dinners in a week, so many people with whom you can be incessantly texting. Medium friends prove the lie in any naïve attempt to be all things to all people."
• "... Reciprocity is the foundation of every friendship: mutual sharing and caring in a context of trust. The tension embedded in medium friendship is this absence of clarity, allowing for the possibility of what Claude Fischer, a sociologist at the University of California, Berkeley, referred to in an interview as “asymmetric expectation”: You may like your medium friend less (or more) than they like you. ..."
• "Scholars who study social networks have attempted to classify the strata of friendship. “Best,” “close,” “good,” “casual” and “acquaintance” is one taxonomy they use. “Support clique,” “sympathy group,” “friendship group,” “clansmen” and “acquaintances” is another. ..."
• "... In a widely cited 1993 article, [Robin Dunbar] posited that humans have the brain capacity to maintain about 150 friendships, with five or six at the very core (including certain family members), 10 to 15 in the second tier, and 30 to 40 in the third tier. The fourth tier encompasses everyone else you are not embarrassed to greet upon meeting accidentally in an airport lounge in the middle of the night. The fifth, gigantic ring is composed of acquaintances."
• "[Dunbar's] research has shown that people move friends out of the innermost circle extremely slowly, about one per decade. ... But at the medium level, there’s a lot of churn. Young adults tend to turn over 30 to 40 percent of their medium friends annually, ..."
• "Some social scientists and even philosophers suggest a different vision of friendship, in which friendship is conceived not as a ledger of emotional debits and credits but as an organic creation — an artwork — built by the friends themselves. Conceived in this way, friendships are not ranked or stratified along a bright line from BFF to near stranger but are instead a perfect mirror of two people’s investment, reflecting their enthusiasms, commonalities, differences and limitations."
• "At its best, a medium friendship can be “almost freeing, without a big sense of obligation,” said [Beverley] Fehr, at the University of Winnipeg. She points to recent research showing that “in a lousy marriage, having good friends will sustain your well-being,” and other studies showing that a wide, diverse friend group composed of weak and strong ties is optimal. ..."

Hmmmm! — perhaps "Friendships", like most things in the universe, should be evaluated in multiple dimensions (spiritual, financial, emotional, erotic, ...), maybe on logarithmic scales, possibly with explicit measurement-uncertainty estimates — and modeled over time with awareness of causality (feedback-loops and time-delays) and chance (random forces) and conflict (clashing motivations and goals)?!

_{(cf Virtual Friendships (1999-11-05), How to Win Friends and Influence People (2008-05-17), Running Friendships (2012-03-06), It's a Big Beautiful World (2021-05-03), Secure Attachment (2022-09-08), ...) - ^z - 2024-06-23}