Daoism, differential equations, and death: Offerings from the seasons

February is ending, 56 degrees latitude, east side island, eastside Atlantic. The world is still shivery but from sky to sky it is blossoming, and my inwardliness is also unfolding outward. The crocuses are sending orange and violet flames from the grass, but this time of growth does not belong to the plants. This blossom is of the Sun and the swift elemental energies it circulates into expression. An aggressive vigour develops the air, hurtles windy momentum, and light breaks new angles between buildings, new geometries cast almost daily now onto the city’s granite floor. My eyes can feel it even if my skin is attuned to a different spring, one that will only appear once lakes and oceans embrace these energies and contribute to them in turn.

Days have been getting longer with the northern tilt’s accelerating plummet toward the fire orb. The stretching of daylight is at first undetectable to my eyes and nose. Measured in seconds added to the day, the solstice holds winter in what seems a catatonic lull, ambiguous in its beginning and end -until one day it isn’t. The shift is felt in ways I live but do not always acknowledge. The alleyway I pass on my morning walk now glitters in light rather than shadow. The difference is felt but not cognised, the stroll feels brighter even if I do not pinpoint why.

The first climax of light will come this year on March 20th at 9:58 pm, but this climax like all celestial transitions, comes with its paradoxes.

Between March 10th and March 26th, days will be getting longer by 4 minutes and 40 seconds every day. Between winter solstice and this time, days were getting longer more and more quickly, after march, days will be getting longer more slowly. We are now rushing towards this peak in vim, after which will be its ageing and senescence. The official first day of birth is the first day of death. Ostara is an inflection point.

Growing up, our summer break always seem to coincide with my father grumbling that autumn had arrived: the days were now getting shorter (his unsolicited astronomical realism never seemed to raise its head during winter solstice). But as I contemplate the hurtling unfolding before me, it seems summer solstice is already the second autumn of the year (my father might be proud of this pessimistic observation). The rate at which days get longer begins to slow in March, decelerating to a standstill in June.

In other words, we are observing changes, and we are also observing changes to the rate of changes. The latter is what mathematicians call “first derivatives” of differential equations. The first derivative of velocity is acceleration. Let’s follow the seasons with an eye on such rates of change. From June until September, death will gain increasingly in vitality, days not only getting shorter but getting shorter increasingly quickly (and like the initial hiddenness of January’s Spring, this death is hidden for awhile by the slow transition and the lagging heat). When the heat begins to catch up a bit, the loss of light is in free fall and Mabon lurks. His first Spring a hidden bloom: beneath the autumnal gloom, with everything about us is withering back into the ground, the accelerating darknesses pivots and pulls away.

But does it end there?

The cos x curve depicts the rates of change of the sin x curve

If changes in daylight hours etch a sine curve into the galaxy, high school mathematics tells us that changes to these changes is a cosine curve. This is represented as f’(x)sin x = cos x. But the rate of change of the cosine graph is an inverse sine curve (-sin x). There is a technical term for this. The rate of change of acceleration is called “jerk” -a term which is almost certain to confuse any intuitive sense we have of what is going on in the passage of the seasons. Because all derivatives of the sin curve are oscillate with the same amplitude and frequency as the original curve, the only difference we should expect is phasic. But can we experience this?

I think we can. In fact, I have already alluded to it above. Between March 10th and March 26th, days get longer by 4 minutes and 40 seconds every day. This approximation hid the fact that the rate of change at which days were getting longer was itself changing extremely slowly. Days are getting longer more quickly, but longer more quickly more slowly. Compare this to the difference between December 23rd and 24th last year. On December 23rd there was 9 seconds more light than the 22nd. On December 24th, there was 17 seconds more light than on the 23rd. The rate of change in March is almost constant even though it is dramatic. The rate of change is in rapid flux in December even though it is imperceptible. There is a lull at the equinoxes too, but unlike the lull during the solstices, it is a lull where we stop feeling the days accelerating. For a week or so, they just seem to be in an almost steady acceleration.

I believe this is the end of what can be perceived (and this only with some difficulty). Who knows what if further derivatives are picked up on and responded to by other creatures? But the mathematics suggest that the extent to which life and death are intertwined in the seasons goes well beyond what has so far been suggested. The derivative of -sin x is -cos x, and the derivative of -cos x is sin x. After four derivatives, we return full circle. Although this cannot be felt or witnessed, it suggests something very powerful and subtle. Superficially, it evokes the four seasons that are themselves also indications of cyclicity. But the more luminous point is that with sin curves there are an infinite number of rates of rates of change, each an oscillating wave. There is no end in sight. In March, the rate in which the rate of change in daylight is changing, is itself changing too, this rate too is changing, and so on ad infinitum. Wrapped into the dynamics of the sine curve is an infinitely intricate conjoinment of slowing downs and speeding ups. Every inflection point is a turning point governed by a new inflection point.

The fourth derivative of sin x is sin x

The solstices and the equinoxes are all moments where solar expansion and withdrawal switch hands, one birthing process now dying, but within that dying another birth. This reveals in the most acute way a concrete and infinite dialectical contradiction.