In 1766, Scottish philosopher David Hume helped the radical Swiss intellectual Jean-Jacques Rousseau find asylum in England; a few months later, the volatile philosopher accused his benefactor of masterminding a murky conspiracy against him and triggered a virulent response. The argument had nothing to do with philosophy (or Rousseau's dog), but, as in their well-received Wittgenstein's Poker
, the authors use the dispute as a pretext for an engaging rundown of the two thinkers' great ideas—with a big swig of human interest to wash down the philosophical morsels. Their (sometimes excessively) detailed, meandering account of the feud points to something larger: the contrast between the affable, urbane rationalist Hume and the moody, paranoid, emotionally overwrought Rousseau prefigures, they believe, the shift from the Enlightenment cult of reason to the Romantic cult of feeling. The authors widen their vivid portraits of the antagonists into a panorama of the cross-Channel intellectual community that refereed the squabble, taking in the ancien régime salons and their brilliant hostesses and the London and Paris streets where visiting philosophers were mobbed like rock stars. The result is an absorbing cultural history of the republic of letters in its exuberant youth. (Mar.)