I am no physicist, but I have a friend who is a professor of physics. That is to say that I know a few of the terms of physics and some of their meanings, but possess no particular expertise. One of the physics terms that I learned years ago is doppler effect. I learned it in reference to sound. If you listen to the sound of a train whistle, you perceive a sudden change in pitch as the train passes. The same phenomenon is easily observed with an emergency vehicle that has its siren going. Explaining the effect might not be difficult for a physicist, but it is a challenge for me. As I understand it, when the source of the sound waves reaching your ear is coming towards you, each crest of the wave takes slightly less time to travel to the ear than the previous one. As the source gets closer the sound waves become closer to each other and the pitch increases. Once the source passes and begins to recede, the distance between wave crests decreases and the pitch decreases.

This effect plays out not only in sound, but with any type of waves. The effect doesn’t result in a shift in pitch with light waves, but rather a shift in color. Understanding this shift in color allows astronomers to detect and measure the size of distant planets.

In his Pulitzer Prize-winning novel, Angle of Repose, Wallace Stegner briefly explores the doppler effect as a metaphor for history. The central character in the book is Lyman Ward, a retired professor of history. As he writes the story of his grandmother, he reflects on his own. In doing so he notes a sudden shift in perspective between himself and his son. His son has his attention focused on the future and is anticipating things to come while he is looking back, trying to understand the past. He likens the difference of perspective to the doppler effect, speculating that there must be a point in a person’s life when one makes the transition from looking forward to looking back.

Reading the novel has gotten me to speculating about using the doppler effect to explain some of the shifts in focus and understanding that are a part of my retirement. The effect, however, is only a metaphor and all metaphors fail at some point to truly describe reality. I am not even sure that it is a good metaphor. After all, I haven’t suddenly shifted my life focus from the future to the past. I spend a lot of my time thinking about the future with eager anticipation. Some future events are relatively close, such as a planned trip to visit our daughter and her family later this year. Others are more distant, such as the graduations and marriages of our grandchildren and perhaps even the birth of great-grandchildren. I do look forward to a great deal of things. I’m looking forward to receiving our second Covid vaccination tomorrow. It should bring a sense of relief and perhaps a sense of increased freedom even though we will continue to observe precautions to help prevent the spread of disease.

I do, however, think of the past and try to figure out how my heritage and my own life story have shaped my perception of the world. When I discuss theology, I nearly always bring the history of Christianity into the discussion. Along with generations of faithful people, I think a great deal about the long history of faith and the origins of our faith.

Another way in which the doppler effect fails as a metaphor for my current life situation is that I am not experiencing the shifts of retirement as sudden. There was a specific date of retirement for me. I had a last day in the pulpit of the church I was serving. In the next week I turned in my keys and credit cards and I stopped going to the office. Since that time, I have continued to work, but I have not been working at a job for pay. The paychecks stopped coming. We started to draw on our savings to meet our expenses. We applied for Social Security. I can sleep in as late as I want most days. I rarely use an alarm clock any more. Although I can name specific changes that have come on a particular day, other parts of retirement have come slowly. I am only now, more than a half a year later, beginning to think of myself as retired. And there are many things about this shift in my life that I don’t yet understand. It isn’t so much that the pitch suddenly changed as that it is slowly changing. The music of my life is in a new key perhaps, but it remains a tune worthy of dancing.

In Stegner’s novel, it becomes clear why the title “Angle of Repose” is chosen over “Doppler Effect.” Angle of repose is another term from physics. The angle of repose is the steepest angle of the side of a pile of granular material. You can observe it by sweeping sand or gravel into a pile. You can get the center of the pile higher than the sides, but you can only make your pile so high. Adding more to the top spreads out the pile rather than making it taller. The angle of the sides of the pile relative to the floor is the angle of repose.

The angle of repose is a metaphor for our memories. We can only bring so much of our memory to the surface at any given time. In order to focus on any past event, we have to “bury” other memories at deeper depths and there is a limit to how many memories we can have exposed to the surface at any time.

I think I might be a bit better at metaphors than physics, but only marginally so. It appears that I’ll need more time and more reflection to come up with a way to describe the shift in perspective that is occurring in my life.

Perhaps I should go for a paddle and reflect on the way my boat displaces water as I pass, creating a wake that is behind the boat. Or I could take out my rowboat and reflect on the process of sitting with my back to the direction I’m traveling as I look at where I have been. Now there is another metaphor.