This post examines the metaphysics or philosophy of nature behind the Stoic views on community and detachment described in Part 1, and how this metaphysics changed in the later centuries of the school's history. Before going into detail, it will be helpful to contextualize the Stoics' metaphysics within their broader tradition of philosophy. Despite preferring their porticoes to the horticultural environs of their Epicurean contemporaries, a popular Stoic metaphor depicts philosophy itself as a garden where:
Logic is the walls, metaphysics the soil, and ethics the fruit [G. & S., (2012)].
This tripartite division of of the Stoic curriculum was established early on, with these three core academic disciplines each reflected in a respective core practical discipline. Metaphysics leads to "the discipline of desire" directed at amor fati (love of fate) and requires "living in agreement" with what nature/fate has in store for us. Ethics leads to "the discipline of action," which requires living in agreement with all human beings. Logic leads to "the discipline of assent," which requires living in agreement with one's own psychological make-up [Robertson, (2013)].
It is likely that this curriculum was developed by Chrysippus of Soli (c.280–c.206 BCE) who was the most important successor to Zeno, the founder of Stoicism, at his school in Athens. Chrysippus apparently had a very high opinion of himself and mistreated his mentor Cleanthes (c.330–c.230), whom he regarded as too simple-minded for philosophy. But Chrysippus was responsible for systematizing Stoic philosophy, and hence a saying goes: if Chrysippus had not taught, the Stoic school would be naught [G. & S., (2012)].
While solidarity with humanity is part of the discipline of action, which in the schema above is described as deriving from ethics rather than from metaphysics, these ethics are themselves dependent on a metaphysical perspective, as is clear from the garden metaphor. We can also see this in the dynamic of living in agreement, which in each of the three disciplines means cultivating philostorgia (natural affection) toward an aspect of nature. This means that Stoic views on community will be illuminated by understanding their metaphysical underpinnings.
God, the Soul, and Community
After Socrates and the Cynics, the third large influence on Stoicism was the pre-Socratic philosopher Heraclitus (c.535–c.475 BCE), from whom a number of metaphysical views were drawn. The most fundamental of these were monism and materialism [Gaarder, 110]. The world consists of only one kind of substance, and that is matter. Zeno was reportedly an extreme materialist himself, asserting that mathematical and moral truths, and God, as well as the soul, must be composed of matter. He regarded this as "common sense: contrasted against the superstitions of his era [Russell, 261]. Unlike the Epicurean materialists, however, the Stoics were not atomists [Aurelius, Bk. X, §6]. Instead, they thought in terms of the four elements of water, earth, air, and fire.
Fire was, as for Heraclitus, the most primal of the elements, and the human soul was made of it. This discouraged belief in life after death because the fire-matter was presumed to dissipate at death. Similarly, the Stoics believed that when the universe came to an end the other elements would be absorbed into fire. As in many ancient belief systems, the universe was viewed as cyclic rather than linear, and hence the universe would be reborn, and the other elements would emerge from fire again. This cataclysmic event was known as the "conflagration" [Russell, 261].
The Stoics also adopted Heraclitus's view that everyone was intimately bound to the order of the universe, known as the Logos (reason). Part of this order is the natural moral law, which, as we saw in the previous part, has inner virtue as its supreme good. The Logos is present within each individual, which is how the natural law can be comprehended intuitively. A distinct consequence of this concept was that Stoics regarded each person as a microcosmos in whom the macrocosmos of the universal Logos is reflected. On this view, the individual and the universe are as one, just as there is no distinction between spirit and matter [Gaarder, 110]. And as each microcosmos is personal, so is the macrocosmos. The macrocosmos has its own soul composed of fire, only this fire is eternal, surviving each conflagration. This world-soul, the Divine Fire, is God himself, revered by Stoics as "Zeus" [Russell, 262].
In keeping with Stoic materialism, although Zeus is the Creator, he is not separate from the world—as Greek philosophers usually conceived of God—but an immanent part of it. Nor is he the bearded Mt. Olympus resident of Greek mythology. Rather, the Stoic God is present within us because the fire of each person's mortal soul “contains a part of the Divine Fire” [Russell, 262], which is immortal. It is because the Stoics regarded the Logos as well as the world-soul as identical with Zeus (a view made possible by their materialism) [Russell, 264], that they believed all human beings share in the Logos, too. Hence Marcus Aurelius can say: the “soul and reason which every man carries within him” is a “divinity which is God's deputy” [Aurelius, Bk. V]. Chrysippus agreed with Zeno that the human soul was mortal, but introduced a degree of life after death. His view was that the souls of the wise survive in a disembodied existence “until the next... conflagration (when everything is absorbed into God)” [Russell, 265].
The greater significance of these views is not so much that each individual can be regarded as a manifestation of God, but that they explain the strong emphasis on community in Stoicism described in the preceding Part 1 to this article, and the necessity of the discipline of action mentioned at the start of this part. The latter is primarily the cultivation of oikeiôsis (natural affinity for others), so that we act out of greater regard for the reality that we are all one. For example, when faced with an ungrateful person, Aurelius recommends we remain mindful that they are close family—“our minds being both extracted from the Deity” [Aurelius, Bk. II, cf. Bk. XII, §19].
Fate and Detachment
The Stoics were not only interested in speculative philosophy and ethics, but in the physical world also. A key corollary of their thoroughgoing materialism was determinism. This is the view that the universe unfolds solely according to material cause and effect, and hence humans cannot change the pre-determined future. Each of us has a fate, an unchangeable future, and a key aspect of Stoicism is the discipline of desire mentioned above, which is working to embrace that fate rather than alternatives we might desire to occur. This discipline is a source of liberation and consolation because when undesirable things happen, it teaches that they could not have been otherwise, so there is no sense in anxiously wishing we had prevented them or that they had otherwise been different. Such determinism is also grounds for being more readily forgiving of others, and we know from contemporary psychology that this is one of the most effective ways to boost happiness. But of course, this discipline is not dependent on the truth of determinism because even if the future is not exactly predetermined, we still cannot control the way events in the world play out, largely because we cannot bend the laws of nature.
The Stoic concept of fate was also characterized by the belief that Zeus is benevolent, that his providence is good as well as wise. At this point, you may well wonder if this is just a precursor to the Trinitarian dogma of Christianity (albeit one that purported to be materialist), since it includes a benevolent father, a Logos immanent in humanity, and a unitive spirit. How this differs from traditional theistic beliefs, however, is that Stoic providence is not a plan for world history from God's mind that he enacts upon the world. Instead, like the Logos and world-soul, providence is identical with God himself [Russell, 264]. And it is because providence is the same force as the world-soul that it possesses causal power throughout all matter, directing it in accordance with God's benevolent purpose.
This is a view of God more as a process than as a being. The crucial function of this process to ensure that the causal flow of events permits humans to practice inner virtue, to possess Stoic happiness, the possibility of which would be merely contingent without providence. This is a stark contrast with the Cynics, for whom it was mere chance that humans had the capacity to be happy regardless of the circumstances. Chance because they did not believe in a providence or teleology in nature [Cooper, (2011)]. Hence, another way Stoics can find consolation in times of trouble is by considering the world sub specie aeternitatis (from the perspective of eternity), detaching themselves from their present concerns by being mindful that their circumstances are just a small part of a fixed, but ultimately good, divine plan for the future.
(N.B. sources on what the later Stoics believed are limited, so some of the inferences I have made about them may not be completely accurate.)
The Stoic school existed at a time when Greek power was on the wane and Rome was in the ascendant, and Roman philosophy was the fourth large influence on Stoicism. It was Neo-Platonism in particular, rather than any tradition native to the Empire, that had become something of an establishment school, and thereby shaped the development of Stoicism in its later period. Some kind of dualism is essential to any form of Platonism, so the Neo-Platonists used philosophy to argue that matter is not the only kind of thing that exists as there is also immaterial mind.
The Stoic philosopher Panetius (c.185–c.110 BCE) had lengthy visits to Rome, and as head of the school in Athens he abandoned materialism [Russell, 265]. Neo-Platonic thought was embraced by his successor, Posidonius (c.135–c.51), but was rejected by many of his contemporaries [Clark, 40]. Hence the change toward it becoming popular among the wider body of Stoic thinkers was much more gradual. Yet by a century later a transformation had taken place, as evinced by Seneca (4 BCE–65 CE), who describes their dualism in one of his letters to Lucilius:
Our Stoic philosophers, as you know, declare that there are two things in the universe which are the source of everything, namely, cause and matter. Matter lies sluggish, a substance ready for any use, but sure to remain unemployed if no one sets it in motion. Cause, however, by which we mean reason, molds matter and turns it in whatever direction it will, producing thereby various concrete results [Letter 65, §2].
Immaterial mind possessed of reason, now included in Stoic metaphysics, was referred to also as “Cause” because they categorized reality into passive matter and active mind. They regarded every entity and every event as ultimately resulting from an act of mind, from either Zeus or a human being [Cooper, (2011)]. This contrasts starkly with the earlier Stoics who had regarded earth and and water as passive and air and fire as active. Evidently, the theory that soul was composed of material fire had also been abandoned. Some of the later Stoics continued to refer to the fire out of tradition, but it is clear that this was now only a metaphor [Russell, 261].
Nevertheless, it is important to note that Stoic metaphysics did not become Neo-Platonist, but rather moved toward it. Their dualism is perhaps better labelled a "non-reductive naturalism" because, even as late as Aurelius, it did not regard Zeus and matter as different substances but only as distinct "aspects or dimensions" of the one substance of nature [Cooper, (2006), p. 39]. But as mind and matter did become regarded as more distinct, so did God and the world, and indeed Zeus and the world-soul also. While the world-soul seems to have become regarded as an ether, and remained somewhat material, Zeus was the rational mind who animated it. Being immaterial, Zeus was:
spread everywhere through the world-soul, to infinitesimal level, and thereby spread also everywhere through the world-animal’s material body so as to effect its telos for the life history [Cooper, (2011)].
The “world-animal” was a later Stoic term for the cosmos, "whose" soul was animated from within by Zeus. The world-animal's “life history” was a convenient label for a sub specie aeternitatis view of its space-time. Zeus was still identified with the Logos, and was not just wise and caring but a perfect being, and hence his providence was wholly good. Yet he did not enact his providence alone, but in cooperation with adult humans, who, in a softening (though not discarding) of Stoicism's determinism, were now regarded as freely responsible for their own actions, rather than being controlled by the world-soul. Among all animals, only adult humans were regarded as rational, and while acknowledging that their exercise of rationality is flawed, their minds were regarded as wholly of one substance with the mind of Zeus. Rather, that is, than only having a small part of Zeus' mind within them, as earlier Stoics believed. Human minds were each self-directing parts of the world animal's unitary mind, Zeus. This underscored the teaching of the later Stoics that humanity is one body of equals who should aspire to partnership with God [Cooper, (2011)].
By blending its philosophy with that of Neo-Platonism, Stoicism assimilated into the Roman establishment—and with astounding success, demonstrated in the figure of Emperor Marcus Aurelius. And in preaching a compassionate brotherhood/sisterhood of humanity as sons and daughters of God, Stoicism prepared the way for the Empire to accept Christianity in 380 CE. Finally, the Stoic-in-all-but-name philosophy of Spinoza (1632–1677) was a major influence on the Enlightenment. It revived materialist metaphysics with new rational bases, and in the spirit of its age, brought Stoicism's latent belief in political freedom for individuals to the fore.
 As was mentioned in the podcast, the Stoics were successful in the field of logic. Following the introduction by earlier Stoics of the first propositional calculus, Chrysippus developed Aristotle's syllogistic method into more of a predicate calculus [Clark, 39].
 I am not aware of there having been any emphasis on achieving mystic union with all of humanity in Stoic mindfulness practices, as one might expect if this belief were found in a religious context. Which is not to say that Stoicism was free from religious aspects—despite rejecting temples, the strong belief in fate encouraged a variety of superstitious practices, including astrology [Russell, 264].
 Some Stoics would not even have accepted that events could have happened differently in a new universe after a future conflagration, since they believed that the history of the world would repeat itself infinitely [Russell, 261].
 This trades one serious objection for another. While it offers something of an answer to how practitioners of Stoicism are able to maintain inner freedom in a deterministic world [Russell, 273], it raises the problem of the lack of any evidence for this providential force. It looks like an unfalsifiable belief that no evidence could disprove, despite the appearance that a distinct lack of virtuous behavior has been preordained by any benevolent providence ruling our universe [Russell, 262].
 Epicureanism was also popular in the Roman Empire but was never as popular as Neo-Platonism, in part because its hedonism was widely slandered as encouraging carefree indulgence—see Horace's writings, for example.
 Posidonius was a sometime teacher of the Roman polymath Cicero (106–43 BCE), and Russell contends that is through these two men that Stoicism gained currency among the Roman elite [Russell, 265].
 For a succinct yet comprehensive comparison of Stoicism and Christianity see this article by the philosopher Jules Evans. To discern a secular philosophy for modern life from the teachings of Jesus, similar to how the Stoicism Today project approaches those of the Stoics, see my series of articles starting here.
Aurelius, Marcus Antoninus, (180 CE), Meditations.
Clark, Stephen R. L., (1994), "Ancient Philosophy," in The Oxford Illustrated History of Western Philosophy, Kenny, Anthony (ed.), Oxford University Press.
Cooper, John, (2006), Panentheism: The Other God of the Philosophers, Baker Academic, Grand Rapids (Mich.).
Cooper, John, (2011),"The Stoic Way of Life," the 3rd of his John Locke Lectures, given at The University of Oxford.
Gaarder, Jostein, (1991), Sophie's World, Phoenix, London.
Garvey, James & Strangroom, Jeremy, (2012), The Story of Philosophy: A History of Western Thought, Quercus, London.
Robertson, Donald, (2013),"An Introduction to Stoic Practice: the Three Disciplines of Stoicism."
Russell, Bertrand, , (1984), A History of Western Philosophy, Unwin Hyman Ltd., London.
Seneca, Lucius Annaeus, (c.65 CE), Moral Letters To Lucilius.
Peter Hardy is an administrator on the Partially Examined Life Facebook Group and has participated in Stoic Week for three years. You can follow him on Twitter. This article previously appeared on his website.