I have never gotten a fix on owning things. I don't mean things like a car or a Cuisinart. I mean things like a beach or a mountain or an idea.

Once when I was nine or 10 and walking along the Main shore, I came across a sign that said: "No Trespassing. Private Property." Even at that age, I wondered: What do these people own? The sand, the water? Do they own the land at low tide or high tide? Are the clams and the fish theirs, too?

It is, when you think about it, really strange to chop up the environment into deed-sized pieces and call it our own. Yet it is also one of the oldest and most universal of human drives.

When I bought my own house seven years ago, I thought about it all again. Why was it that I could buy a half-acre of land and not of sea? Was land really mine to buy? What about the slugs and seelings? To this day, when I walk around my backyard, I think of "my lilac and "my" vegetable garden with pride, and yet some amusement.

I am equally intrigued by the relationship between what we create and what we own. I cannot, for example, patent the idea in a column as my own, insisting that anyone who thinks it or discusses it from now on owes me a royalty. I can put a copyright on a book, but not on a way of looking at the world.

If I were an artist, I could on a painting, but not impressionism. I could sell a record, but not the rights to jazz. I could patent a piano or an easel or a typewriter, but never sue anyone who adopted my style at one of these instruments.

Now, this week, the Supreme Court has ruled in a rather timorous, tentative voice that we can patent life. A scientist in Chicago, Dr. Ananda M. Chakrabarty, through genetic engineering produced a hungry organism to eat the oil we spill. Five of the members of the court have said that he -- or General Electric, to be specific -- can apply for a patent to make, own and sell this living thing. It will be theirs.

Had this man discovered, rather than invented, an organism that ate up oil spills, he could not have patented it. Newton could not have owned the law of gravity. Crick and Watson could not have taken a patent out of DNA. These discoveries, as the court reminded us, are "manifestations of nature, free to all men and reserved exclusively to none."

It is only the act of human creation, and the creation of something tangible, "useful," manufacturable, man-made that can be exclusively owned.

To be specific, as an earlier court ruled, "Whoever invents or discovers any new and useful process, machine, manufacture or composition of matter or any new and useful improvement thereof may obtain a patent therefore."

The patent is the deed, then, that General Electric can take out of bacteria, as if this species were a camera. They have ruled that Dr. Chakrabarty's discovery is not nature's handiwork, but his own. They have allowed us to patent life because it is "useful."

It seems to me that the whole issue of ownership is here perfectly tied up with human motivation and productivity. We allow people to own something, in order that they will produce, in order that they can own something else. It is called "incentive."

The Patent Act of 1793 was built on the notion that Jefferson shared with the other founders of the country, that "ingenuity should receive a liberal encouragement." In order to encourage creativity, we hold out a promise of ownership and profit. In order to make profit meaningful, we encourage more ownership.

The thing that we have in common is the urge to put our stamp, our fence, our mark, our ego on the landscape. I don't say that with scorn; I think it is one powerful human motivation, and not necessarily an evil one.

But the end result of this sort of reasoning is curious. It can lead to a Hollister Ranch syndrome, where a few people pay up to half a million dollars for 100-acre lots near Santa Barbara and shut off 8 1/2 miles of Pacific Ocean beach to the public.

I am not among the people who are freaked out by fantasies of genetic engineering run amok. But I am cautious.

It is bizarre enough in itself to give people rights to life. It is an even odder business to distribute exclusive patents on our biology and project profit on genes. This is not, after all, a digital clock or a calculator. Genes are the most fragile coastline of the entire human continent.