As Anna Harrison was saying to a handful of teen-agers yesterday, science sounds rather orderly if you read it in a book, but it certainly didn't develop that way.

Fits and starts, not to split hairs.

Two thousand years to disprove a postulate of Euclid (or to deny it, and devise new geometries of astounding usefulness) was not too long for science.

And although she didn't say so, scientists do not usually decide at the age of 11 to be Nobel winners, or researchers of major stature, and eight of them are speaking at a twoday session ending today at the Museum of History and Technology, part of the Smithsonian's year-long program of Einstein projects.

They are not talking about results of their work. Their Nobel prizes (five of them), National Medals of Science, Bocher prizes, etc., have marked their work in pharmacology, mathematics, zoology, orthomolecular medicine and so on.

But here they spoke as humans, with hard choices and modest beginnings.

Whether, for example, to take a job in a great lab for $25 a month or to become a postal clerk at $165 a month.

Some planned originally on other careers. In school, I.M. Singer, now professor of mathematics at the Massachusetts Institute of Technology, was more interested in English.

A spoiled poet, you might say. Still, he has done well enough in mathematics.

Julius Axelrod, concerned with what happens to drugs when metabolized in the body, conducting his work at the National Institute of Mental Health, never planned to become a researcher in that field. Instead, he had wanted to study medicine.

Scientists, he said, are produced by bright people going to the best schools and getting on promptly with their advanced degrees.

"But none of that happened to me. I went to City College [of New Yrok]." He was in his 40s before he got his doctorate, and got it only because he was told he couldn't advance (for science has her bureaucrats, too) without one.

He spoke of the financial crunch of marriage and kids. He got a job testing headache powders (why some of them were producing disorders of the blood) and presto:

He had stumbled into his life's work.

Harrison, who was moderator at a session yesterday, warned students not to build walls and rule possibilities out. Why should a person decide he will work in a precise field (before he knows beans about it) and ignore side things that open up? A lot of opportunities, she said, are not noticed as opportunities because of preconceived notions in the head.

Roland Hofman, science counselor of the Swiss Embassy, had taken off a few hours to hear some of the speakers:

"It's incredible to me," he said. "Only in America. In Europe do you think a high school kid could question a Nobel laureate or ask for career advice from him?"

One girl said that as far as she could tell, you had to take all the hardest subjects and somehow get into one of the very best schools, then push push, push for years and maybe at last you might get on the ladder.

"Tragic," said Singer, "But probably true."

The world does not guarantee distinction to children or, for that matter, adults.

Axelrod nodded. Hell, he was 42 before his doctorate. "But don't give up," he urged.

Singer said the thing was not to decide to be a great research scholar, but to learn enough to know what questions could be asked, and to lose yourself in trying to answer a few of them.

To be struck by wonder, to be obsessed with quandaries, to be on fire to find an answer -- that is what science is about, Singer went on, and not some childish dream of playing deep researcher.

He himself had a Sloan fellowship at Oxford and decided to spend the year at Capri, lovely island beloved of the more debauched Roman emperors but beautiful all the same.

There wasn't anything to do but walk and admire grottoes.

He wanted a quiet lovely place where he could work on his mathematics. He got quientness in spades.

"After two months I went back to Oxford," he said. Better the rainy gardens of St. John's College than the sun of Capri. At Oxford he could look things up in books and talk with colleagues.

Like many another, he discovered paradise is not enough -- not nearly enough if you lack the means of work and the stimulation of friends and "friends" who ask hardquestions.

A distinguished- looking scholar in the audience said Einstein had his greatest year of scientific break-throughs at a time he was working in the Patent Office of Berne, and didn't even know another physicist. So he wondered if one really needs books and colleagues.

"We are not," said Singer, "all Albert Einstein."