During the sixteenth and seventeenth centuries a radical change occurred in the patterns and framework of European thought. In the wake of discoveries through the telescope and Copernican theory, the notion of an ordered cosmos of 'fixed stars' gave way to that of a universe infinite in both time and space - with significant and far-reaching consequences for human thought. Alexandre Koyre interprets this revolution in terms of the change that occurred in our conception of the universe and our place in it and shows the primacy of this change in the development of the modern world.