Henry David Thoreau was fond of just wandering into the forest and letting Nature teach him things, that is, by pure experience. He considered this much more important than formal learning, from books and classrooms. But if he relied only on experience, without formal learning, he would get nothing out of his romps in the woods other than a vague feeling of happiness and relaxation. It was because he had formal education that he was able to make sense out of the many things that he experienced in the woods. As I walk through the woods, I encounter many people who get nothing more from their hike than a feeling of relaxation, which is in itself a good thing, but I think I enjoy my ramble in the woods more than they do theirs.
Actually, they aren’t rambles. I always stay on the trail like a good citizen. John Burroughs would stay on the trail and use the bridge, while Thoreau, or John Muir, would pick their way through the woods and jump over the creek.
We need both formal education and continually renewed experience. Here are two examples:
- In my field botany class, I taught students how to recognize poison ivy, in particular the three leaflets and the stalk on the middle leaflet. This is what all the poison ivy figures in the books have. But, especially in late summer, the plants can get a little raggedy. When I was hiking one day, I saw a poison ivy plant. (It was actually a small bush rather than a vine.) It had one leaf remaining, and one of the three leaflets had fallen off. But because I have looked closely at so many poison ivy plants, I recognized it instantly. No written key, not even the astonishingly accurate algorithms of iNaturalist, would have identified this two-leaflet poison ivy leaf. But I recognized the leaflet as I might have recognized the face of a friend, as Thoreau would have said.
- On the same hike, I saw a Virginia creeper vine. All the books say, as I said in class, that the leaves have five leaflets. But this one—the whole vine, which was small and a little pale, obviously not well nourished—had leaves with three leaflets. That is, each leaf had developed three leaflets; it was not a case of five leaflets of which two had been shed. But I recognized it instantly.
These are the sorts of plants I would not include on lab practicals. Had I included the three-leafleted creeper, a student would have said, But you told us there were five.
Formal learning told me how to recognize a typical poison ivy or Virginia creeper; experience, over the course of years, taught me how to recognize the diversity of individual creepers and poison ivies.
One habit that Thoreau had more than almost anyone else, and which we must all cultivate to be wise and happy, is close observation; and, in addition, asking questions about what we see. My former students may forget most of what they learned from me in class, but if they keep looking at the things in nature, they will continually renew their knowledge of things such as poison ivy and Virginia creeper.