In C.S. Lewis’s The Screwtape Letters (if you haven’t read them, see the note at the bottom for context), he observed that human beings live according to cycles. It’s in the beginning Letter 8:

Humans are amphibians—half spirit and half animal. (The Enemy’s determination to produce such a revolting hybrid was one of the things that determined Our Father to withdraw his support from Him.) AS spirits they belong to the eternal world, but as animals they inhabit time. This means that while their spirit can be directed to an eternal object, their bodies, passions, and imaginations are in continual change, for to be in time means to change. Their nearest approach to constancy, therefore, is undulation—the repeated return to a level from which they repeatedly fall back, a series of trough and peaks. If you had watched your patient carefully you would have seen this undulation in every department of his life—his interest in his work, his affection for his friends, his physical appetites, all go up and down. As long as he lives on earth, periods of emotional and bodily richness and liveliness will alternate with periods of numbness and poverty. The dryness and dullness through which your patient is now going on are not, as you fondly suppose, your workmanship; they are merely a natural phenomenon which will do us no good unless you make a good use of it.

Our lives are lived according to many cycles, some independent, some interrelated. What Lewis refers to as troughs and peaks are actually the lining up of many troughs at the same time, or many peaks at the same time. What are these cycles?

There are some obvious cycles, like the diurnal cycle we live in every day (day/night). There are longer cycles, like weekly, monthly, and yearly cycles, too. Work weeks, weekends, pay days, construction seasons, busy season, and all sorts of other cycles affect us. But probably least well appreciated are feedback cycles.

It’s not uncommon when feeling well rested to make the mistake of staying up too late. If we do this a little bit we get progressively more exhausted during the days until we simply can’t do it and start getting enough sleep. Once we’ve gotten enough sleep, we’re ready to start getting too little sleep again.

Another common feedback cycle is the stress cycle. When we’ve got plenty of emotional energy, we tend to be more tolerant of people taking up our time and placing demands on us which consume a lot of emotional energy.  More things on our to-do list, more leniency for people being annoying, more patience with people being rude or unappreciative. Lots of things can consume emotional energy which we can deter or allow to consume more. The better we’re feeling the more generous we tend to be. But as that continues, our surplus gets used up. Depending on what we tolerated, this might have resulted in increased demands past the rate at which we replenish emotional energy. This continues until we’re emotionally exhausted and start being defensive of our energy. This might result in simply turning things down, or it might result in bad temper. (Like all cycles, one deals with it best when one is realistic about it; letting oneself get pushed to complete exhaustion is a terrible idea because it makes us most likely to explode at small irritations.)

There are other feedback cycles in life, like entertainment versus unpaid work or spending time with friends versus solitude. They’re all around us, if we look for them. There’s value to identifying them, but life is complex enough that we also need to be able to recognize when there are cycles we don’t know about at work. Some days we just feel awful and if it’s the result of cycle troughs lining up, it may just be time to go to bed early and soon things will be better. Some days are great because of peaks lining up and it can be a good idea to take advantage of them rather than expect them to be the new normal. It’s also helpful to try to recognize the feedback loops and smooth them out—especially the troughs—by anticipating them and adjusting before things get too extreme.

We live tossed around in the waves. It’s a good idea to learn to surf instead of being tossed around, gasping for breath.

About The Screwtape Letters

The Screwtape Letters are written as a series of letters from the demon Screwtape to his “newphew”, the demon Wormwood. Wormwood is the demonic parody of a guardian angel assigned to a human being to try to corrupt him and trick him into damning himself. Only Screwtape’s letters offer advice to his “nephew” on how to do his evil work. All of Screwtape’s letters are good advice on how to damn a soul; as such they are really advice on how to live well (in the sense of being upright or good) presented in what you might call photographic negative. What is good, Screwtape calls evil; what is evil, Screwtape calls good. But that’s true in all cases, so one very easily learns the habit of just flipping everything around.

Reading the book—which is excellent, and I highly recommend—is an interesting experience. Probably the closest analogy I can come to is honestly examining one’s conscience for faults with the intention of improving.