在光学中，光的微粒理论，被皮埃尔·伽桑狄在争论中逐步确立，托马斯·霍布斯声称光是由被称为小体(微小颗粒)的离散颗粒组成，以光速并带有冲力沿着直线行进。这是基于当时的原子论所提出的。

In optics, the corpuscular theory of light, arguably set forward by Pierre Gassendi and Thomas Hobbes, states that light is made up of small discrete particles called "corpuscles" (little particles) which travel in a straight line with a finite velocity and possess impetus. This was based on an alternate description of atomism of the time period.