From The Paris Review:
Philia, the root of Philadelphia, roughly translates to “friendship” in Aristotle’s Nicomachean Ethics, an enduring source for understanding the ethics of friendship. Aristotle identifies three essential bases for friendship: utility, pleasure, and virtue. Friendships of virtue, Aristotle believes, are ideal because only they are based on recognition. When I was thirty, I moved back to Philadelphia. I had only been gone a few years, and though I knew better, I had half expected it to be just as I’d left it. It was not: most of my friends had left the city altogether or moved, married, to the edges of town. Occasionally, I would run into people I had once known, encounters that produced deep and surprising embarrassment in me; unexplained life choices digested in fast, always alienating, appraisal. The more unsettling thing was that my close friendships were changing, too.
Friendship has never seemed both more important and less relevant than it does now. The concept surfaces primarily when we worry over whether our networked lives impair the quality of our connections, our community. On a nontheoretical level, adult friendship is its own puzzle. The friendships we have as adults are the intentional kind, if only because time is short. During this period, I began to consider the subject. What is essential in friendship? Why do we tolerate difference and distance? What is the appropriate amount to give? And around this same time, I discovered the curious, decades-long friendship between the writers Sherwood Anderson, Theodore Dreiser, and the sculptor Wharton Esherick. Their relationship seemed to me model in some ways; they were friends for over twenty years, mostly living in different cities. Each man was dedicated to pursuing his own line of work, and the insecurities and single-mindedness of ambition seemed analogous too to the ways that adulthood can separate us from our friends.