Opening paragraphs..............................

      "The fumes which rise from the bottom of a swamp produce frogs, ants, leeches, and vegetation ... Cut a groove into a brick, fill it with crushed basil, and put another brick on top to seal the groove.  Within a few days the vegetable matter will have turned into scorpions."  So claimed a seventeenth-century savant called Jean-Baptiste Van Helmont.  But although Van Helmont lived in the seventeenth century, he belonged far more to its past than its future, for he was one of those whose understanding of the world relied on ideas developed centuries before his own time.  The ideas in question belonged to an intellectual tradition that encouraged belief in miracles, spontaneous generation, and phoenixes rising from ashes.  In this tradition it was an unquestioned fact that the sun and stars go round a stationary earth, with God's heaven above and hell-fire at the earth's centre.  Yet even as Van Helmont premised this notions in his writings, a new world of ideas was coming into existence around him.  One of the chief of those bringing about this change was Rene Descartes.
-A.C. Grayling,   Descartes:  The Life and Times of a Genius