Second impression. "An argument for the existence of a mental see saw which in the last 250 years has affected a wide range of human attitudes and activities. When the see saw tilts to extreme optimism or pessimism, all kinds of attitudes, normally seen as unconnected, move too. A variety of intellectual activities and movements are partly under the sway of the seesaw, but its powerful influence is rarely noticed. A knowledge of the see saw helps to explain events that seem as far apart as the oil crisis of the 1970s and the counter culture of the 1960s, the high confidence of the mid-nineteenth century and the Cult of the Noble Savage in the era of Rousseau and Captain Cook. The author argues that the present economic crisis has close links with the see saw, though the see saw itself is more than an economic mechanism." (publisher's blurb