Where Science Is Headed -Hl- SERIES CONCLUSION. Breadth of knowledge will be as required as depth to solve the 21st century's problems

WERE it not for Scientific American, A.C. Gilbert's chemistry sets, and high-school Latin, modern American science might be significantly different. That's one of many conclusions arising from recent interviews with eight leading American scientists.

It's not that courses taught in school played no part in drawing these individuals into science. It's that the real enthusiasm for science often grew up at home in parallel with those courses. It sometimes developed in basements, garages, barns, and under porches as 10-year-olds tinkered with gadgets or collected plants and insects. It matured through reading about recent scientific discoveries, often in Scientific American magazine. And in more than one case, it found an outlet not in science but in studying that most scientific of languages, Latin.

And in math. ``I just loved math,'' recalls space scientist James Van Allen.

``How I became a physical scientist is probably hard to explain,'' says theoretical physicist Shirley Jackson, ``except for my interest in mathematics. When I was a little kid, I used to play mental [arithmetic] games.''

But loving math was not essential. Particle physicist Leon Lederman never took to math. Astronomer Sidney Wolff slogged through high-school algebra only because her father made her.

Teachers, too, played a strong role. Molecular biologist Leroy Hood praises three high-school teachers - one of whom didn't teach science. Chemist Mark Wrighton and anthropologist Robert Adams each point to a college professor, while Leon Lederman singles out a high-school lab assistant and an Italian 'emigr'e physicist in graduate school. Biologist Peter Raven, however, points not to a person but to an institution: the California Academy of Sciences, which he joined at the age of 8.

Could an observer have predicted scientific careers for these youngsters? Not in all cases. Dr. Wolff finally chose science only as a college sophomore, when her two loves - Latin and astronomy - met at the same hour. Mark Wrighton went to college to study communications; Robert Adams planned to be a journalist.

Then what did these young students have in common? They all loved to learn - taking delight, in many cases, in their sheer ability to understand seemingly esoteric things without demanding immediate relevance. In addition, they were willing to work hard - recognizing, as Dr. Van Allen says, that ``things are really hard to understand.'' They put a premium on intellectual curiosity and imagination, along with patience, dedication, and drive.

And what about the rewards? One way or another, each talked about the fun of doing science - about their vocation becoming their avocation. For most of them, the real fun came at the moment of breakthrough when, after years of work, ``you know something that nobody else in the world has ever known,'' as Wolff puts it.

The picture of the late 20th-century scientist that emerges, then, contradicts what Lederman calls the Hollywood image of ``the guy in the white coat who says, `I vill destroy the vorld tomorrow!''' More importantly, it helps dispel the stereotype of the researcher as anti-social nerd, burrowing into a narrow specialty and speaking jargon with haughty disregard for the social implications of science. Successful scientists these days are often keenly aware of those implications - in part because the costs of basic science (which the federal Office of Management and Budget estimates at about $10 billion a year) are borne largely by taxpayers.

Perhaps even more important in shaping the character of today's scientists is the character of modern science. Several interlocking trends are evident:

The compelling problems facing 21st-century science lie along the interfaces between disciplines. The three traditional sciences - biology, chemistry, and physics - are increasingly intermingled as researchers ask questions no single discipline can answer. And they are reaching out to engineering and electronic technology - not to mention ethics and management science - in order to move forward.

As a result, scientists increasingly work in groups that sometimes number more than 100, pooling their knowledge and bringing different theoretical insights and experimental talents to bear on a single problem. The days of the lone investigator working with a few test tubes and a Bunsen burner have all but disappeared as even small labs fill with computer-driven equipment.

The recognition of complexity is driving science away from fragmentation and toward the study of problems not as isolated phenomena but as strands woven inextricably into a larger context. The study of complex systems and of the relation of parts to the whole, in fact, increasingly characterizes all branches of science.

At the same time, the ``dimensional regime'' of science is expanding in both directions. Physics, once done with visible balls, levers, and springs, now focuses on lengths and spaces almost inconceivably small. Astronomy deals with distances measured in billions of light-years. Similar changes have occurred in biology and chemistry.

Individual scientists, encountering the above trends, have been forced to expand their breadth of understanding. As a result, their careers have tended to make them not narrower, but broader, as they scramble to keep up with developments in allied fields.

Yet they often confess that they can no longer keep up with cutting-edge knowledge in their own discipline. ``I can't even understand two-thirds of the colloquia in this department,'' says Van Allen. ``It sounds like a pretty strong statement, but I think it's impossible for anyone in physics to really know what's going on in a broader sense these days in the subject.''

On one thing these scientists agree: There are rich frontiers of science ahead in the 21st century. From secondary metabolites to superconductivity, from ancient civilizations and the formation of the universe to femtosecond spectroscopy and the arrangement of nucleotides in the human genome, the areas that science will be probing will require plenty of talent and provide plenty of opportunity for scientists.

So why should 10-year-olds consider careers in science? Because ``it gives you a feeling of mastery,'' says Van Allen. Because there are 5 billion people on the planet, and what you discover might be ``so profound that it will affect all of their lives,'' says Lederman. And because, as Dr. Raven says, ``I really, genuinely, thoroughly enjoy what I do.''