In 1959 C.P. Snow published a book titled The Two Cultures. On the one hand, there were the literary intellectuals; on the other, the scientists. He noted with incredulity that during the 1930s the literary intellectuals, while no one was looking, took to referring to themselves as "the intellectuals," as though there were no others. This new definition by the "men of letters" excluded scientists such as the astronomer Edwin Hubble, the mathematician John von Neumann, the cyberneticist Norbert Wiener, and the physicists Albert Einstein, Niels Bohr, and Werner Heisenberg.

How did the literary intellectuals get away with it? First, people in the sciences did not make an effective case for the implications of their work. Second, while many eminent scientists, notably Arthur Eddington and James Jeans, also wrote books for a general audience, their works were ignored by the self-proclaimed intellectuals, and the value and importance of the ideas presented remained invisible as an intellectual activity, because science was not a subject for the reigning journals and magazines.

In a second edition of The Two Cultures, published in 1963, Snow added a new essay, "The Two Cultures: A Second Look," in which he optimistically suggested that a new culture, a "third culture," would emerge and close the communications gap between the literary intellectuals and the scientists. In Snow's third culture, the literary intellectuals would be on speaking terms with the scientists. Although I borrow Snow's phrase, it does not describe the third culture he predicted. Literary intellectuals are not communicating with scientists. Scientists are communicating directly with the general public. Traditional intellectual media played a vertical game: journalists wrote up and professors wrote down. Today, third-culture thinkers tend to avoid the middleman and endeavor to express their deepest thoughts in a manner accessible to the intelligent reading public.

The recent publishing successes of serious science books have surprised only the old-style intellectuals. Their view is that these books are anomalies--that they are bought but not read. I disagree. The emergence of this third-culture activity is evidence that many people have a great intellectual hunger for new and important ideas and are willing to make the effort to educate themselves.

The wide appeal of the third-culture thinkers is not due solely to their writing ability; what traditionally has been called "science" has today become "public culture." Stewart Brand writes that "Science is the only news. When you scan through a newspaper or magazine, all the human interest stuff is the same old he-said-she-said, the politics and economics the same sorry cyclic dramas, the fashions a pathetic illusion of newness, and even the technology is predictable if you know the science. Human nature doesn't change much; science does, and the change accrues, altering the world irreversibly." We now live in a world in which the rate of change is the biggest change. Science has thus become a big story.

Scientific topics receiving prominent play in newspapers and magazines over the past several years include molecular biology, artificial intelligence, artificial life, chaos theory, massive parallelism, neural nets, the inflationary universe, fractals, complex adaptive systems, superstrings, biodiversity, nanotechnology, the human genome, expert systems, punctuated equilibrium, cellular automata, fuzzy logic, space biospheres, the Gaia hypothesis, virtual reality, cyberspace, and teraflop machines. Among others. There is no canon or accredited list of acceptable ideas. The strength of the third culture is precisely that it can tolerate disagreements about which ideas are to be taken seriously. Unlike previous intellectual pursuits, the achievements of the third culture are not the marginal disputes of a quarrelsome mandarin class: they will affect the lives of everybody on the planet.

The role of the intellectual includes communicating. Intellectuals are not just people who know things but people who shape the thoughts of their generation. An intellectual is a synthesizer, a publicist, a communicator. In his 1987 book The Last Intellectuals, the cultural historian Russell Jacoby bemoaned the passing of a generation of public thinkers and their replacement by bloodless academicians. He was right, but also wrong. The third-culture thinkers are the new public intellectuals.

America now is the intellectual seedbed for Europe and Asia. This trend started with the prewar emigration of Albert Einstein and other European scientists and was further fueled by the post- Sputnik boom in scientific education in our universities. The emergence of the third culture introduces new modes of intellectual discourse and reaffirms the preeminence of America in the realm of important ideas. Throughout history, intellectual life has been marked by the fact that only a small number of people have done the serious thinking for everybody else. What we are witnessing is a passing of the torch from one group of thinkers, the traditional literary intellectuals, to a new group, the intellectuals of the emerging third culture.