In other words, he argues, the big problems that can be solved have been, and the big ones that haven't been solved can't be. Among the celebrated thinkers quoted in this ambitious book are Stephen Jay Gould, Roger Penrose, and John Archibald Wheeler. A concise history of the last 20 years of scientific study introduces his thesis and covers such topics as superstring theory, mathematical topology, and how to distinguish chaos from complexity. From Publishers Weekly Scientific American columnist Horgan here interviews an impressive array of scientists and philosophers, who seem sharply divided over the prospects and possibilities of science. Among the pessimists, molecular biologist Gunther Stent suggests that science is reaching a point of incremental, diminishing returns as it comes up against the limits of knowledge; philosopher Thomas Kuhn sees science as a nonrational process that does not converge with truth; Vienna-born thinker Paul Feyerabend objects to science's pretensions to certainty and its potential to stamp out the diversity of human thought and culture. More optimistic are particle physicist Edward Witten, pioneer of superstring theory (which posits a universe of 10 dimensions); robotics engineer Hans Moravec, who envisions superintelligent creative robots; and physicist Roger Penrose, who theorizes that quantum effects percolating through the brain underlie consciousness.