In the seventeenth century, at the end of the Ming and the beginning of the Ch'ing dynasties, China produced three outstanding scholars: Huang Tsung-hsi (1619–95), Ku Yen-wu (1613–82), and Wang Fu-chih (1619–92), all great thinkers, voluminous writers, and ardent patriots. The social and political chaos, economic deterioration, excess of Wang Yang-ming's intuitionism, and, above all, the conquest of China by the Manchus must have stimulated the best minds to develop their ideas in a more practical direction. They were contemporaries of René Descartes 1596–1650) and Blaise Pascal (1623–62) and only slightly earlier than Isaac Newton (1642–1727). Confined by their cultural tradition and living in a vast but largely isolated empire, these men naturally developed ideas different from those of their European contemporaries. But they had enough challenges of their own to meet. The originality in their ideas bespeaks the intellectual vigor of late imperial China.