Twenty-plus years later I was watching  the Twilight Zone and was startled when a short episode consisted of my story. There was the machine, the person who wanted to stay in it, everything. Obviously, I thought, someone had read the story and used it as the basis for the television program – without, however, paying royalties.

 I contacted the producers and received a telephone call from Harlan Ellison. I was star struck because I had been reading and admiring his science fiction for years, so I was predisposed to believe what he told me.

 The story had evolved through parallel evolution, Harlan insisted. He sent me a stack of scripts that showed how the story had changed from version to version and arrived at a similar form by a different route. I accepted his explanation.

 Recently I reviewed some stories written in my forties to see if I could revise them. One called Learning Curve used the device of a time machine to show how a middle-aged man looked back on mistakes he had made growing up, mostly due to decisions he made about how to interpret what was happening. Those decisions determined his identity, and identity is destiny – who we think we are is how we choose to express our lives – so the middle-aged man went back to critical moments in his history to try to teach his younger self a better way, to give himself the benefit of his wisdom.

 Each time he tried to teach himself a lesson, however, it was beyond the grasp of the younger person. At the end, when he ventured to the recent past and saw himself trudging up the walk to his home, his spirit deflated by a recent divorce, he realized he had nothing else to say; all he could do was step out of the shrubs, tell himself that he understood, and hold his younger self while it cried.

 Once he learned to be compassionate toward himself, he stopped looking backward and could move forward again.

 That story had promise, I thought, because of its emotional  truth. But I am not going to revise it because, in the years since, a movie starring Bruce Willis called The Kid told a similar story. People would think I had stolen a plot device that was already trite when I used it.

 The writers of the script arrived at a similar plot by parallel evolution, I imagine, and if I could see the revisions of the script before it took final form, it would probably resemble what Ellison had sent.

 A decade later, I relate the story as much to mentoring as to introspection. When we mentor someone, particularly when we are in our fifties and they are in their twenties and thirties, we are talking not only to them but also to our younger selves, but this time with compassion. Some mistakes are inevitable, we know, and we can’t learn what we need to know without the detours that turn out to be the most direct route to maturity.

 Several of our children were with us recently and it was a wonderful time. Everybody is an adult now and we relate to one another less as parents and children than as older and younger adults. My youngest son whose motorcycle accident I described in a former column, writing in the waiting room of the ICU after we knew he would live, was one of our visitors. He has healed and we are grateful.

 My son and I stopped for a latte late one afternoon. Through the coffeeshop window on the Milwaukee River, we could see the woods which had not yet filled with snow and the cold river. We watched the trees thicken and dissolve in the dusk as we talked about the transitoriness of all things, his deep and terrible insight into the nature of appearances and what we call realities. We tried to make our lattes last, stretch the canvas of time over the frame of the lengthening shadows. We spoke the most real things we know. But at last the twilight knitted the trees into an inscrutable darkness and we had to go.

 That conversation is a self-referential image, it is what it was about. It is a transparent stained glass window illuminating movement with illusory images of fixity.

 Was there any way for either of us to learn what we know by an easier route? Was there any way for me to relieve the ones I love of the necessity of traveling their own roads? I guess not. As my forever-unpublished story pointed out, the only road is the one we walk. The knowledge of the impermanence of all things creates in us if we are paying attention a compassionate heart which is willing to listen and understand and at the end embrace and feel both love and the hard edges of boundaries defining our individual destinies.

 There is no greater joy than loving and mentoring when we can, but I know now that whenever I mentor another, I am really healing my younger self who longed at critical moments for someone older, more knowing, more loving, to show up and just be there. The grace of my life has been the realization that whenever I really needed that, someone did. Their faces are in the lighted hallways of my memories, portraits of my own personal saints, the ones that matter most. Nor does it diminish their contribution or value to know that they too reached their mature selves by a process of evolution parallel to my own and that they too were talking not only but also to themselves.