Common experience as well as sophisticated analysis confirm that this is an age of uncertainty. There is a supreme irony in the inescapable observation that the forces of rationalism and scientific experiment — the legacy of Bacon, Descartes and Spinoza — are now expressed in a world of seemingly irrational turbulence and daunting complexity. The three major symptoms of this are global: the threat of ecological disaster, economic disorder, and the menace of nuclear annihilation (after Bernal 1969).