The mind of man acts by an instrument necessarily. The το 'ηγεμονικον, or Mind presiding in the world, acts by an instrument freely. Without instrumental and second causes there could be no regular course of nature. And without a regular course, nature could never be understood; mankind must always be at a loss, not knowing what to expect, or how to govern themselves, or direct their actions for the obtaining of any end. Therefore in the government of the world physical agents, improperly so called, or mechanical, or second causes, or natural causes, or instruments, are necessary to assist, not the governor, but the governed.
Berkeley, Siris, section 160.
