In 1763, the young James Boswell finished his “London Journal,” one of the frankest accounts of high and low life in the eighteenth century. The following year, he embarked on a Grand Tour. In a Berlin tavern, he encountered a certain Neuhaus. This voluble personage of thirty-nine, unusually tall, with a dark complexion and affected manners, was an Italian who “wanted to shine as a great philosopher,” Boswell wrote, “and accordingly doubted of his own existence and everything else. I thought him a blockhead.”