Abstract
Our understanding of the world is not static; it can both expand and contract, and it can also stagnate. In history the expansion of the known universe has come about from various causes, from scientific advance, the slow processes of trade and exploration, from, colonization, and especially from conquest. Periods of expansion produce often a re-evaluation of the external world, both that which was already known and that which was previously unknown, or on the fringes of the known. But no one is wholly capable of a direct response toreality: reality as soon as it is experienced is perceived, organized: ‘Die Welt ist die Gesamtheit der Tatsachen nicht der Dinge’