Stoicism, Physics

According to the Stoics, the Universe is a material reasoning substance (logos), which was divided into two classes: the active and the passive.^[62] The passive substance is matter itself, while the active substance is an intelligent aether or primordial fire, which acts on the passive matter, the logos or anima mundi pervading and animating the entire Universe. It was conceived as material and is usually identified with God or Nature. The Stoics also referred to the seminal reason ("logos spermatikos"), or the law of generation in the Universe, which was the principle of the active reason working in inanimate matter. Humans, too, each possess a portion of the divine logos, which is the primordial Fire and reason that controls and sustains the Universe.^[63] Everything is subject to the laws of Fate, for the Universe acts according to its own nature, and the nature of the passive matter it governs.

Stoicism does not posit a beginning or end to the Universe.^[64] The current Universe is a phase in the present cycle, preceded by an infinite number of Universes, doomed to be destroyed ("Ekpyrosis"), conflagration) and re-created again,^[65] and to be followed by another infinite number of Universes.