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Thanks Bryan - it's a shame that we do focus on the term "atom" as if he were concerned about a particular object, when what he really was concerned about the logical imperative that there must be a limit to a division of both bodies and space!
It's so much easier for people to dismiss him by putting him in a box labeled "atoms" than to realize that what he's really campaigning against is the use of logic divorced from sensation to overthrow the senses.
Episode 328 of the Lucretius Today Podcast is now available. This week our episode is entitled: "Sensation - While Neither Right Or Wrong - As The Touchstone Of Reality"
There are several major omissions in the existing list and I will eventually revise it. In the meantime and while I think about the existing structure and consider any incoming comments, here are four more that I am going to add:
Epicurus cures this by showing that the length of a life and the quality of a life are two entirely different things. As he states directly in the Principal Doctrines, "Infinite time contains no greater pleasure than limited time, if one measures by reason the limits of pleasure." The pleasure of a good meal is complete when hunger is satisfied; the pleasure of a deep friendship is complete in the living of it; neither of these is improved by being repeated forever. The demand for immortality as a condition of a meaningful life is therefore a confusion — it mistakes duration for value and treats the good life as something that can only be justified if it never ends, which is precisely the kind of thinking that prevents people from fully inhabiting and appreciating the life they actually have.
Epicurus cures this by drawing a precise and liberating distinction between the removal of pain — which is the actual goal — and the endless addition of more stimulation on top of it. He states in the Principal Doctrines that "the limit of quantity in pleasures is the removal of all that is painful," and further that once the pain of want is removed, pleasure is not increased by adding more — it is only varied. Once hunger is fully satisfied, you are not in a state that requires ever-larger meals to maintain your happiness; you are already at the natural limit of that pleasure. This matters enormously because the belief that pleasure is always deficient and always demands more to sustain it is the very engine of insatiable desire — the endless pursuit of wealth, novelty, and stimulation that Epicurus identified as one of the chief sources of human misery.
Epicurus cures this by showing first that happiness is not a moment-by-moment condition but a property of a whole life, and second that a whole life well-lived is fully capable of including pain without being destroyed by it. The question is never whether any particular day is free from suffering, but whether your life as a whole — looked at honestly from beginning to end — contains more pleasure than pain, and whether you are able to appreciate and enjoy that life as the complete thing it is. Just as a good day is not ruined by a difficult hour, a good life is not cancelled by periods of pain, and the mind has a remarkable capacity to draw on the entire span of one's experience — on the memory of past pleasures, on the pleasures of friendship and reflection available right now, and on the confidence that what lies ahead holds no terrors — in a way that can outweigh even serious physical suffering. In the Principal Doctrines Epicurus states that extreme pain tends to be brief, and that pain which does persist over time does not typically hold its most intense levels for long. More importantly, Epicurus himself demonstrated the whole argument at his own death: writing in his final hours while in severe physical pain, he reported that the joy he felt in remembering his philosophical conversations with friends set itself against all of it. He was not claiming to feel no pain. He was showing that a life rich enough in genuine pleasure — built over years through friendship, thought, and the practice of living well — carries resources that physical suffering alone cannot take away.
Epicurus cures this by showing that justice is not a set of eternal rules handed down by a god from above but something that real people create for themselves through agreements made under specific circumstances. In the Principal Doctrines he states plainly that Justice as a single thing in itself does not exist in nature. What exists are agreements among people in particular places and times about how to avoid harming one another for their mutual benefit. This means that what counts as just can and does change as circumstances change: an agreement that served mutual protection under one set of conditions may need to be revised or replaced when those conditions shift, and clinging to old arrangements simply because they once worked is not justice but rigidity. The demand for a single, timeless, universal standard of justice — whether grounded in divine law, abstract reason, or natural right — is itself a source of harm, because it blinds people to the actual human purpose that justice serves and makes it harder to adapt agreements to the real conditions of real communities.
For reference as to the term mind virus
This thread will be used for discussion of the new beginner-friendly article: Mind Viruses Cured By Epicurean Philosophy. Please add comments, suggestions, etc. here.
Very useful Eikadistes! n They are arranged in chronological order?
I don't know that we used it in this episode, but there's another phrase that we should probably be referring to more often in this discusion: "the whole is greater than the sum of its parts" - which has to be explained as a natural phenomena rather than implying anything supernatural.
At around the 20 minute mark in this episode Joshua refers to an important David Sedley observation, but we did not have the quote at hand. Here is the full section, from his "Epicurus' Refutation of Determinism," with the main part Joshua was referencing underlined:
In confirmation of this, we can return to the close and apparently conscious parallelism between Epicurus' treatments of determinism and scepticism. The sceptics refuted in Lucretius IV must be, or prominently include, those fourth-century Democcriteans like Metrodorus of Chios, Anaxarchus, and even Epicurus' own reviled teacher Nausiphanes, who had played up the sceptical side of Democritus' thought, and against whom Epicurus was eager to marshall the positive empiricist arguments which Democritus had also bequeathed. This scepticism was the result of what I shall call reductionist atomism. Because phenomenal objects and properties seemed to reduce to mere configurations of atoms and void, Democritus was inclined to suppose that the atoms and void were real while the phenomenal objects and properties were no more than arbitrary constructions placed upon them by human cognitive organs. In his more extreme moods Democritus was even inclined to doubt the power of human judgment, since judgment was itself no more than a realignment of atoms in the mind.
Epicurus' response to this is perhaps the least appreciated aspect of his thought. It was to reject reductionist atomism. Almost uniquely among Greek philosophers he arrived at what is nowadays the unreflective assumption of almost anyone with a smattering of science, that there are truths at the microscopic level of elementary particles, and further very different truths at the phenomenal level; that the former must be capable of explaining the latter; but that neither level of description has a monopoly of truth. (The truth that sugar is sweet is not straightforwardly reducible to the truth that it has such and such a molecular structure, even though the latter truth may be required in order to explain the former). By establishing that cognitive scepticism, the direct outcome of reductionist atomism, is self-refuting and untenable in practice, Epicurus justifies his non-reductionist alternative, according to which sensations are true and there are therefore bona fide truths at the phenomenal level accessible through them. The same will apply to the pathe (feelings), which Epicurus also held to be veridical. Pleasure, for example, is a direct datum of experience. It is commonly assumed that Epicurus must have equated pleasure with such and such a kind of movement of soul atoms; but although he will have taken it to have some explanation at the atomic level, I know of no evidence that he, any more than most moral philosophers or psychologists, would have held that an adequate analysis of it could be found at that level.
I think in a survey of the history of philosophy, Berkeley is one of the best examples of an Idealist. Whereas, for Plátōn, the world of matter that traps souls in cages in not made of mind.
It's a constant stuggle to decide how much diving into the details is sufficient. However it seems pretty clear to me that the ultimate goal is being sure that we have a grasp of the "big picture" regardless of the twists and turns of how some of these philosophers seek to distinguish themselves individually. Everyone seems to want to make a name for themselves with new jargon, but I see very little in the end that makes any real difference.
At the moment i am hard-pressed to come up with a better high-level way of expressing it beyond what Nietzsche was apparently doing with his "true world" figure of speech (such as in Twilight of the Idols). No matter how you slice it between mind or matter or any other single word, it seems like the issue always comes back to whether we are going to choose to live and die by the senses in this world, or by something we think we can identify only in our minds in another world.
Eikadistes if you come up with equal or superior ways of summarizing these issues please be sure to highlight them. I know a lot of people get frustated and simply pass over discussion of the details, and that's probably OK - just so they have an outline/higher-level understanding of the real dividing lines.
In the case of most if not all of these philosophers who are variants of Platonism or any form of idealism, I'm not sure that it's necessary to know much more than their orientation toward the relative value and roles of the senses vs the mind - at least that's the way I see it at the moment.
I just ran a search of this forum and after more than ten years of activity I don't see a single mention of the phrase "castles in the air." It is highly irritating to me that the first use of this very appropriate characterization of anti-Epicurean philosophies has to come from ClaudeAI. However - I'll take it. Now that I think about it I haven't heard the phrase used much at all in many years . Here's the resurrected application, followed by Don McLean (who might be responsible for my remembering it at all). I feel sure that there are at least a couple of others who will remember the same reference.
What is striking is how consistently the same Epicurean moves apply:
Every form of modern idealism, in different ways, interposes something between the knower and the world — divine mind, cognitive apparatus, Absolute Spirit, irreducible qualia. In every case Epicurus would say: the Canon does not attest to this interposition, and each of these additions generates more problems than it solves while delivering less than Epicurean materialism already provides cleanly.
The deeper issue is that modern idealism, like its ancient predecessors, typically begins with a puzzle (how do we have certain knowledge? what is consciousness? how can contingent things exist?) and then constructs a metaphysical architecture to solve it. Epicurus's method runs in the opposite direction: start with what the Canon delivers and build only as far as the evidence warrants. Any architecture built higher than that foundation is, regardless of its internal elegance, a castle in the air.
George Berkeley is relevant to this discussion, so here's a summary of the issue there:
Berkeley's Subjective Idealism ("esse est percipi")
Berkeley attacks the very foundation Epicurus stands on — the reliability of sensation as a guide to external reality. Berkeley argues that material substance is an incoherent concept: all we ever actually have is perception, and "matter existing independently of mind" is something no one has ever experienced or could experience. Therefore minds and ideas are all that exist.
Epicurus's response would be aggressive and direct. Berkeley's argument is self-refuting by the Canon's standards: it uses the evidence of perception to deny the external world that makes perception intelligible. For Epicurus, sensation is not a veil between us and reality — it is a contact with reality. The eidōla (films of atoms) that strike our sense organs are literally from the objects perceived, carrying structural information about them. The causal chain from object to perception is physical and real.
More pointedly, Epicurus would note that Berkeley's "ideas in the mind of God" sustaining reality is simply the Platonic move in different dress — replacing the physical world with a mental/divine substrate that the Canon cannot reach. The argument is that Berkeley has traded one metaphysical claim (matter) for another far more extravagant one (universal divine mind).
We don't crawl in a hold and die and give way to AI because AI isn't alive, doesn't care, and will never fight for what it values as a human being. But if AI can help provide weapons of immediate value faster than we could find answers ourselves, I'm ready to pick up that weapon.
This answer is based on what living people have produced, but do I know any living person who can answer Aristotle better than this? If I do know such a person, please point out where the following might be wrong! Because it sure sounds consistent with all my past reading on Epicurus.
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The case of Aristotelian case is actually a harder problem for Epicurus than Plato's Ideal Forms, because Aristotle had already made the key concession Epicurus would demand of Plato.
Why It's a Different Problem
Against Plato, Epicurus's objection is relatively straightforward: Forms existing in a separate realm are simply unreachable by the Canon and do violence to the evident facts of reality consisting of bodies and void. Plato puts ideal forms or "essences" above the physical world.
Aristotle pre-empts that objection. He agrees there is no separate realm of Forms. Essences are immanent — they exist in particular things, not above them. The essence of color is not floating in a Platonic heaven; it is in colored things, and the intellect abstracts it from sensory experience. This is much closer to Epicurean territory, and Epicurus cannot simply dismiss it as empty transcendentalism.
The Epicurean Counter: Prolēpsis vs. Essence
The key Epicurean move is to deploy the doctrine of prolēpsis (preconception) as an alternative account of exactly what Aristotle thinks essences explain.
When we encounter red things repeatedly, we form a general mental concept — a prolēpsis — of color. This concept is real, it is useful, and it is derived from sensation. But for Epicurus it is a cognitive construction built from accumulated sensory encounters, not a perception of an immanent universal structure residing in things. The distinction matters enormously: Aristotle thinks the intellect is discovering something that is really there in the world; Epicurus thinks the intellect is constructing a useful generalization from what sensation provides.
So the Canon gives us particular colored things. Full stop. Aristotle's "essence of color" is what happens when a mind operates on that sensory data and mistakes its own generalization for a feature of external reality.
The Atomic Account Does Additional Work
On something like color specifically, Epicurus has a second line of attack: color is not a primary property of atoms at all. Atoms have shape, size, and weight — that is all. Color (and taste, sound, smell) are emergent properties arising from atomic arrangements in relation to a perceiver. They are real as experienced — Epicurus is not a skeptic about color experience — but they have no essence to be abstracted because they are relational and contextual, not intrinsic structural features of things.
This directly undercuts Aristotle's example. You cannot abstract the essence of color because color doesn't inhere in things as a stable immanent form waiting to be intellectually grasped. It is produced at the intersection of atomic structure and percipient organism.
The Teleology Connection
There is a deeper reason Epicurus must reject Aristotelian essence, and it goes beyond epistemology. Aristotle's essences are not merely descriptive — they are bound up with his teleology. The essence of a thing includes its telos, what it is for, what counts as its flourishing or completion. To ti ēn einai — "the what it was to be" for a thing — carries this purposive dimension throughout Aristotle's natural philosophy.
Epicurus rejects natural teleology root and branch. There is no "what things are for" in a world of atoms and void moving by weight, impact, and swerve. If there is no telos in nature, then Aristotelian essence — which is form-as-telos immanent in matter — simply has nothing to latch onto. The entire framework requires a purposive nature Epicurus denies.
Here's another logical conundrum: Why don't we just all crawl in a hole and die when AI can provide excellent answers that we might never be able to construct ourselves?
In the meantime while we ponder that, here's an articulate Epicurean response to Avicenna:
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Avicenna's argument is one of the most sophisticated theistic proofs ever constructed, and engaging it forces Epicurus to work at his deepest levels.
Avicenna's Argument in Brief
The Burhan al-Siddiqin runs roughly:
Its elegance is that it doesn't start with motion or causation in the ordinary sense — it starts with existence itself and the essence/existence distinction.
Epicurus's Responses
1. Reject the essence/existence distinction at its root
Avicenna's entire architecture depends on distinguishing, in contingent beings, what a thing is from that it is — essence from existence. The Necessary Existent is then defined as the one being where this gap collapses.
Epicurus would attack this as precisely the kind of empty abstraction the Canon cannot support. What sensation, prolepsis, or feeling gives you essence as a thing separable from an actually existing entity? These are scholastic constructions built in the mind, not features of the world the Canon attests to. The distinction is a linguistic and logical artifact, not a discovery about reality.
2. The matter and void are themselves the "Necessary Existent"
This is perhaps the sharpest Epicurean counter. Epicurus held that matter and void are eternal and uncreated — they have always existed and cannot not-exist. If Avicenna wants to say there must be something whose non-existence is impossible, Epicurus hands him atoms and void and says: here it is. You have simply re-described Epicurean first principles in theistic language and added nothing.
Avicenna would object that matter is still contingent in his sense — but Epicurus would reject the terms of that objection, since they depend on the essence/existence distinction already refused in point 1.
3. The infinite regress prohibition is simply asserted, not demonstrated
Avicenna claims a chain of mutually contingent beings cannot extend infinitely — that the whole chain would remain without a ground. But Epicurus explicitly and deliberately accepted an infinitely deep causal past. The universe has always existed; atomic interactions have no first moment. For Epicurus, demanding that a causal chain terminate is importing a logical intuition — that explanation must bottom out somewhere — and treating it as a metaphysical necessity. The Canon does not attest to this. It is an intellectual preference dressed as a proof.
4. The Canon directly blocks the conclusion
Following his standard methodology: the Necessary Existent is posited as something outside the natural world that grounds it. But Epicurus held that the gods, whatever they are, exist in the intermundia and are entirely uninvolved in the workings of the cosmos. More fundamentally, the concept of a being outside nature whose essence IS its existence is not derivable from sensation, prolepsis, or feeling. It is precisely the kind of concept generated by pure dialectical construction — the thing he was most suspicious of. No amount of formal validity in the argument licenses a conclusion that the Canon cannot reach.
5. The argument misuses "necessity"
Necessity for Epicurus is a property of arguments and propositions, not of beings as such. To say the atoms necessarily exist is a loose way of saying they have always existed and the evidence gives us no reason to think otherwise. It is not a deep metaphysical property inhering in them. Avicenna's move requires necessity to be an ontological feature that some beings have and others lack — a kind of modal metaphysics Epicurus would simply refuse to enter.
The Bottom Line
Epicurus would say Avicenna has constructed an impressive logical structure, but it is built entirely above the ground floor of what the Canon can support. The key moves — essence/existence distinction, the impossibility of infinite regress, the concept of necessary existence as an ontological category — are all products of pure dialectical reasoning untethered from sensation and experience. At each joint where the argument needs the world to cooperate with its logic, the world (as Epicurus understands it) simply doesn't.
And characteristically, Epicurus would not merely deflect: he would say the positive account — eternal matter, eternal void, infinite atomic motion with no first cause and no external ground — already explains everything Avicenna's argument was trying to explain, without requiring any entity the Canon cannot reach.
Also, in relation to how the atomism arguments fit in relation to the other logic-based issues:
Where the Common Thread Applies
The starting point is the same: Zeno's conclusion — that motion is impossible — is directly contradicted by sensation. We see things move. That is a Canon-level datum, and no formal argument can override it. So in that sense, Epicurus's first move is identical to his handling of the Liar or the Sorites: the argument reaches an absurd conclusion, therefore the argument is wrong.
But Here Epicurus Goes Further
With the Liar Paradox and the Sorites, Epicurus was largely content to dismiss the argument as a verbal or dialectical trap and move on. He didn't feel obligated to locate the precise flaw.
With Zeno's paradoxes he did something more demanding: he identified exactly where the argument goes wrong and replaced it with a positive physical theory. The false premise is infinite divisibility. Magnitude is not infinitely divisible — both atoms and the distances they traverse have genuine minima, smallest parts that cannot be further subdivided even conceptually. This doesn't just block Zeno's conclusion; it gives you a coherent account of how finite traversal of finite distances is physically possible.
The Deeper Point
So the minimal parts doctrine represents the Canon working at its most constructive. The Canon tells you the conclusion is false; reason then has the obligation to find the defective premise and build a correct account in its place. This is Epicurus at his most systematic — not just deflecting bad logic, but doing genuine physics in response to it.
It also shows that his anti-dialectical stance was not laziness or ignorance. When the stakes were high enough — when a logical argument threatened to undermine the entire intelligibility of the physical world — he would engage it fully on its own terrain and win on those terms.
I searched and added a series of other logic-based arguments, and this was suggested as the general common thread uniting the responses:
The Common Thread
What unites Epicurus's responses is a consistent methodological stance: formal logical arguments, no matter how clever, never override the Canon. If an argument leads to a conclusion that contradicts sensation, prolēpsis (common preconceptions), or the evidence of feelings, then the argument is wrong — even if you cannot immediately identify the flaw in its premises. This made Epicurus unusual in antiquity: he was not anti-rational, but he was firmly anti-dialectical in the sense that he refused to grant pure logic jurisdiction over empirical reality.
Infinite Regress Arguments for God as First Cause
While not exclusively Zeno-derived, various thinkers used infinite regress arguments to argue for a divine unmoved mover. Epicurus rejected the premise structure: he held that matter and motion are eternal and self-sufficient, requiring no external initiator. The infinite past of atomic motion is simply given — there is no logical compulsion to terminate a causal chain at a god.
(Need to expand)
Logical Fatalism / the Idle Argument (Argos Logos)
Related to the above, the Idle Argument ran: "If it is fated that you recover from this illness, you will recover whether you call a doctor or not; if it is fated that you do not recover, you will not recover whether you call a doctor or not; therefore calling a doctor is pointless." Epicurus attacked this as a practical reductio — the argument destroys the meaningfulness of deliberation and action, which are attested facts of experience. The atomic swerve was in part a physical mechanism designed to block precisely this kind of fatalistic conclusion.
Need references for this!
The Master Argument (Kyrieuon Logos) of Diodorus Cronus
This is perhaps the most philosophically important case. Diodorus constructed an argument that only the actual is possible — i.e., if something did not happen, it was never truly possible. This had direct bearing on Epicurean physics because it threatened atomic swerve (the parenklisis/clinamen): if determinism rules and only what occurs is possible, the swerve has no logical space to exist. Epicurus needed possibility to be real and open to preserve both the swerve and human free will. His counter was not to refute Diodorus's formal logic term by term, but to insist that the Canon and the evidence of human deliberative experience directly attest to real open possibility — and that no formal argument can override what is self-evident to experience.
(Need references for this)
The Liar Paradox ("This statement is false")
The Liar Paradox was a favorite of the Megarians (attributed to Eubulides). Epicurus famously dismissed it as not worth serious engagement — essentially calling it a verbal trick rather than a genuine logical problem. Cicero reports that he was criticized for this dismissiveness, but Epicurus held that the Canon grounds truth in relation to real objects of cognition, and a self-referential sentence with no object in the world simply falls outside the scope of genuine inquiry. His critics (especially the Stoics) thought this showed ignorance of logic; Epicurus would have said it showed wisdom about what logic is actually for.
(Need references for this)
That said, I'm happy to leave the refutations to those inclined that direction.
RIght - those who are interested, please contribute; those who are not - no worries.
