《沉思录·卷八·行事与本分》第57条
The sun appears to be poured down, and in all directions indeed it is diffused, yet it is not effused. For this diffusion is extension: Accordingly its rays are called Extensions [[Greek: aktines]] because they are extended [[Greek: apo tou ekteinesthai]]. But one may judge what kind of a thing a ray is, if he looks at the sun's light passing through a narrow opening into a darkened room, for it is extended in a right line, and as it were is divided when it meets with any solid body which stands in the way and intercepts the air beyond; but there the light remains fixed and does not glide or fall off. Such then ought to be the outpouring and diffusion of the understanding, and it should in no way be an effusion, but an extension, and it should make no violent or impetuous collision with the obstacles which are in its way; nor yet fall down, but be fixed, and enlighten that which receives it. For a body will deprive itself of the illumination, if it does not admit it.
注释摘要
奥勒留在这一条里用一个物理世界的光学现象来阐明智性应当如何运作。比喻的核心是“扩散”却“不流溢”，他在希腊语中特意辨析了光线（aktines）与“延伸”（ekteinesthai）的词源关联，这不是修辞游戏，而是尝试用自然哲学来锤炼伦理态度。从斯多葛的物理学看，宇宙是一个连续体，渗透一切的普纽玛（pneuma，气息）以不同的张力等级赋予事物以存在、生长、感…