The Metaphysics of Stoicism: 3 Key Tenets

What did the Stoics believe about determinism, the cosmos, and its underlying reality?

Feb 13, 2024By Luke Dunne, BA Philosophy & Theology
metaphysics stoicism key tenets


One of the most fundamental philosophical questions is the study of Being—the study of exploring nature and reality. Many philosophers, in particular ancient ones, took their stance on how the world was created and what the underlying principles of nature and reality are. Stoics, too, came up with a physical theory of their own, determining Being as a material matter. But what was it exactly that they saw as the underlying principle of nature? And, more importantly, how was the world created from it?


1. How Was the Cosmos Created According to the Stoics?

zeno stoic philosophy
A bust of Zeno of Citium (334—c. 262 BC), the founder of Stoicism, photo by Paolo Monti, 1969. Source: Wikimedia Commons.


First, let’s explore the big metaphysical picture about how the world came to be according to Stoicism. For the Stoics, the entire world, or cosmos, is made out of four elements: fire, water, air, and earth. Everything is made up of their mixtures and compounds, all in constant motion.


Like Plato in the Timaeus, the Stoics believed the cosmos is alive in some sense; but while Plato postulated a separate creator that gave the world a soul, the Stoics show a preference for a radically unified conception of the cosmos. There is a divinity that makes the cosmos alive, but it is material and immanent throughout the cosmos, being called “Zeus” or “god” or “Nature”, and identified with the purest form of the element fire.


According to them, fire has varying properties, both creative (or “technical”, that is, craftsmanlike) and destructive. Creative fire is the element responsible for life and motion.


plato cunego etching
Plato, Etching by D. Cunego, 1783, after R. Mengs after Raphael. Source: The Wellcome Collection.

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This is how, according to the Stoic theory, the universe came to be, and how anything was created. The starting point of the world, where all that exists is the fiery perfection of god, is Zeus, and that is pure fire.


For some reason known only to god’s perfect rationality, creation begins when part of the divine fire condenses into a liquid containing the seed of all future objects and changes. The liquid then undergoes two further transformations. Some of it vaporizes into air and some condenses further into earth. Pure elemental fire also remains. Thus, the evolving cosmos now has all of its basic material components.


However, it’s important to mention that the world is only partially stable. The power of the fire increases over time in an orderly pattern and one day in the distant future its “fuel” (derived from the other elements) will be exhausted and the entire cosmos will become a flame, returning once again to its singular starting point. Then the whole process repeats again, repeating itself forever.


Although there are various (little) changes throughout the whole Stoic tradition, the basic picture of Stoic cosmology outlined here is one that the school stayed with throughout its long history.


2. Logos and Fire in Stoicism

chrysippus stoic philosophy
Statue of Chrysippus of Soli (279—c. 206 BC), the third leader of the Stoic school, photographed by Marie-Lan Nguyen in 2011 at The British Museum. Source: Wikimedia Commons.


Now, let’s get a bit deeper into the significance of the most fundamental principles in their metaphysics—fire and logos. For the Stoics, the immanent rational principle guiding the world’s changes was a form of fire that has a kind of life-giving breath—pneuma. Pneuma was a traditional word for breath, but for the Stoics, it became a technical term that meant the animating force in the world.


In our ordinary observation, the element fire has more of a destructive than a life-giving character, but the Stoics give it the role of creative force and the property of pneuma. Fire represents the active and transformative nature of the universe, as well as the underlying principles that govern it.


The universe, they believed, is governed by a rational and divine principle that they referred to as “Logos.” They saw this Logos as a fiery, active force that pervades all things and brings order and harmony to the cosmos, and fire represents the dynamic and creative nature of the Logos.


statue heraclitus
Bust of Heraclitus by unknown Italian artist, 18th century. Source: Sotheby’s.


Furthermore, the Stoics differentiated two kinds of fire: the active fire and the passive fire. The active fire, also known as the creative fire or the generative fire, represents the active principle that brings about transformation and growth in the universe. It symbolizes the dynamic and creative nature of the divine Logos. This active fire is seen as the source of life and vitality, driving the processes of growth, change, and development in the world.


The passive fire, on the other hand, represents the recipient or receptor of the active fire. It refers to matter or the material world that undergoes transformation through the influence of active fire. Passive fire is seen as the receptive element that is acted upon and shaped by the active fire’s creative power.


They believed that these two fires, the active and passive, are inseparable and interconnected. They saw the active fire as permeating and animating the passive fire, giving it life and form. Together, these two fires represent the dynamic interplay between the creative force and the material world.


seneca stoic philosophy
A bust of Lucius Annaeus Seneca the Younger, the most notable thinker from the late Stoa, unknown artist. Source: Wikimedia Commons.


Aristotle, whose cosmology is in some ways very similar to that of the Stoics, had held that the cosmos was eternal, sustained by a non-physical god “outside” it, a god that serves as the ultimate and unchanging mover of the cosmos.


The Stoic cosmos is radically unified and its sustaining god is not external. For them, god is the productive, active, or ‘creative’ feature of the world, penetrating everywhere. The creative feature that they are mostly referring to is fire, and they give it sort of a god-like character. That’s why they often mention it under the name of Zeus.


3. Stoic Cosmology About Different Beings and Entities

panaetius stoic philosophy
Panaetius of Rhodes (c.  185—c.  110/109 BC), stoic philosopher from the middle period. Source: Etsy UK.


Now let’s take a look at the Stoic’s cosmology. According to Stoic cosmology, there are various classes of various kinds of entities in the world. They distinguish four levels of such entities by the kinds of capacities which they exhibit.


The simplest beings are inert (minerals, for example) and their essential capacity is merely the possession of basic attributes and the ability to hold themselves together as unified objects. This “holding together” and possession of basic attributes are described as their hexis (a term derived from the Greek verb ‘to have’).


More elaborate are things that can grow, nourish themselves, and reproduce. Plants are the best example, and they are held together and kept alive (because they are alive in a way that minerals are not) by their physis (or ‘nature’). Plants are not self-moving and don’t perceive, although they do react to their environments in limited ways.


The next level is the animals, which are perceptual self-movers. The principle that makes them what they are is not just nature, but a ‘soul’ or psyche. Things with souls (animals) have more powers than just nourishment and reproduction. They can also perceive, desire, and move.


Humans are located on the level above the animals because their souls are even more sophisticated in virtue. They have rationality. And it is because of reason (logos) that they are the rational soul. Humans do everything that lower entities do but do so rationally. This means that we have the capacity to respond critically to our perceptions and to process and manipulate them as well. On the top of the scale is the perfect logos or the God(s). They are not even classified into the four layers of entities, because they are beyond the scale to begin with.


4. The Stoic Doctrine of Causation and Determinism

marble bust marcus aurelius
A Roman marble portrait bust of the Emperor Marcus Aurelius, circa 170–180. Source: Christie’s.


Stoicism’s doctrine of causation and determination is an important one to analyze because out of all the views that they held, this is the one that caused the most controversy. First, they recognized that only matter can act or be acted upon, and so all causes are relationships between bodies. Secondly, they stated that there can be no uncaused events or entities. That is because the rational power of divine pneuma is what causes things to be what they are and do what they do. Consequently, they come up with their third postulate, and that is that everything in the world is predetermined. But, they make this determinism so demanding and so strict, that their determinism even progresses into fatalism. Fatalism suggests that everything is predetermined and that there is no place for change at all. So, this leaves us with no way for us to do something that can contribute to the changes of events in the world because there is nothing that we can do that isn’t already predetermined. This is what caused the most controversy.


zeus bronze sculpture
Jupiter au foudre de Bouillac (or, in the Greek style, Zeus), 1st century AC. Source: Ministère de la Culture.



Everything that happens in the world is part of a coordinated network of causes, effects, events, and objects, and this network is the expression of a master plan aimed at the best possible outcome.


There are many philosophical objections to this form of determinism, but two, in particular, stand out. First, if everything is caused, what about human actions? Are my actions, decisions, and even my thoughts determined in advance by the ‘will of Zeus’? Does that mean that in some sense I am not free to make real choices, that I am a sort of puppet? That’s the first objection.


The other one concerns all the bad things that go on in the world. If all the events happening in the world are aimed at producing good, how is there so much badness in the world? If there is a divine plan causing everything in the world, why isn’t everything perfect, or at least a great deal better than it seems to be?


Many Stoics gave their efforts in trying to answer these issues, especially the Roman emperor Marcus Aurelius. Some may say that they satisfy the depth of the philosophical elaboration that’s needed, but some do not think so. This is partly why their determinism doctrine remains the most controversial theory of theirs to this day.

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By Luke DunneBA Philosophy & TheologyLuke is a graduate of the University of Oxford's departments of Philosophy and Theology, his main interests include the history of philosophy, the metaphysics of mind, and social theory.