The sunlight diminishes perceptibly now. The plants know.

The past week we've eaten deep purple eggplants and bright pink brandywine tomatoes, yellow summer squash and green-and-red striped beans. Today we will pick basil for pesto, some for tonight, some for February. A bowl full of ripe blueberries waits for us, sunlight incarnate.

But the sunlight is dying, and the plants know.

We do not speak of religion in class, at least not formally, though students will occasionally ask religious questions, and I will deflect them. I explain that some things cannot be known through science, and that what I believe beyond the limits of science falls outside the province of class.

In class we talk of light and hormones, photoperiods and abscisic acids, to explain how plants know. We talk under the hum of fluorescent lights, time marked by defined blocks of time. In class, September light is exactly the same as February light, and class is always 48 minutes long, no matter where the sun sits.

Sunset today marks the start of Lammas, or Loaf Mass Day--joy for the harvests that are coming and regret for waning sunlight. Lammas used to be celebrated--the first wheat berries of the year were ground into flour and baked into bread offered in thanks, some used for Communion, some for the feast that followed.

We thank God (or Tailtiu or Lugh or some other forgotten gods)--harvest time reflects death and grace, whatever the culture. Death and grace feel foreign in the classroom, indeed foreign in our culture. We pretend, at our peril, that life is linear.

Lammas falls halfway between the summer solstice and the autumnal equinox. The days are shortening, winter is coming. Until you feel the seasons in your bones, until you follow a grain of wheat from the ground to plant to bread to you then back to the ground again, the modern myths may be enough.

Science can explain why plants produce fruit when they do, and I can teach the steps. We can test whether a student learns what I present, and the students that do this best have access to all our culture offers.

You can become very powerful, very rich, without knowing grace. You can go far in life if blessed with intelligence and beauty, degrees and citations, without ever knowing what a wheat berry looks like, without ever kneading a lump of flour and water and yeast into glistening dough.

In the end, we don't know much, and may never know much. We can, however, recognize grace. We might not grasp it rationally, but we we can grasp it--a good reason to celebrate Lammas.

The Skeleton of Death dances every hour in Prague--photo of the Prague Astronomical Clock by Sandy Smith found on VirtualTourist.