Since the bridge in Minneapolis collapsed, the world has become bridge-conscious. In natural law class this semester, I said to the students: “What is the ‘natural law of bridges?'” I was thinking of J. M. Bochenski’s chapter on “law” in his Philosophy: An Introduction.
Bochenski shows that a relation exists between the mind and the cosmos. A bridge, built by men from antiquity to the present, is designed to provide a way over a river, chasm, or other obstacle. Bridge builders understand the mathematical and geometric principles enabling them to design a bridge precisely. They know the qualities of stone or other material used in construction.
Thus, bridge builders know the laws of the materials they work with: distances, stress, and other elements that go into construction. If they make a mistake in design, the bridge will collapse. Collapsing bridges indicate a correspondence between mind and reality: Our minds know enough about reality to find and use its laws. Once the bridge is built, the “laws” are present in the bridge itself, making it what it is.
Often I walk across the Key Bridge, just below our campus to the Virginia side across the Potomac. It is a handsome, high bridge with several arches. I said to the class, “What does one think before crossing a bridge?” First, he assumes that the natural law of bridges is at work within the Key Bridge. Usually we do not think of this, but implicitly assume it. If we did not, we would not put a foot on a bridge.
Secondly, we assume that we are beings who can walk. Man is Homo ambulans. Other animals walk, of course. Our walking is a function of our definition: animal rationale. When we walk across a bridge, we do so for a purpose, not just “to get to the other side.” Why do we want to go to the other side? A thousand different reasons, good and bad, exist. We do not always cross for the same reason, but we walk, granted that we could drive, fly, swim, or take a boat if we either wanted to or had to.
Walking across the Key Bridge from Virginia, we see the Three Sisters Islands. We note the tide from the bay, in or out, the trees along the shore, the boat houses. On the rise, we see the towers of Georgetown. On the opposite side, we see the curve in the river, the Kennedy Center, the Washington Monument, and Roosevelt Island. Overhead are often planes coming in and out of Reagan National Airport, while below are boats of various shapes and sizes.
Having some trouble with my leg, it has become difficult to walk, a favorite Schall occupation. Suddenly, what it means to be a being that can walk, who has local motion under the control of his mind and will, takes on a new sense. We did not give ourselves the make-up we have whereby we walk. We find we have it without thinking about it. The world could never work if we did not walk; it is preliminary to almost everything we do.
So why do we cross a bridge? In the spirit of Hazlitt’s famous essay “On Going a Journey,” we walk because it is itself an exhilarating experience. Yet the perfection of walking a bridge is not the fact that we have legs, or that the natural laws of bridges are put there by our minds, evidently in conformity with the Mind that made things in the first place to be what they are. The natural laws of bridge-building were in existence even before there were men who built bridges.
Yet we walk across the bridges never giving a second thought to the laws of bridges or to the fact that we have legs and can choose what to do with them. If we are not the bridge builders, the bridge is either useful, or beautiful, or pleasant, or sometimes dangerous when its inner laws do not work or our purposes in walking are wrongful. The Last Bridge may also be destroyed in wartime.
Man is Homo ambulans. This is part of his natural law, the law of reason. This endowment enables him to get to places about his home or to the top of Mount Ranier. Walking is a kind of natural reflection of man’s mind, which is capax omnium, capable of knowing all things. His walking takes him to places he knows. The natural law indicates that relation between all our natural endowments, including our two legs, and our knowing all that is. Our walking is a reminder that there really are places and realities outside our minds to which we want to go, at which we want to be present.