Plain English Guide to Technical Jargon in Epicurean Philosophy
It is the intent of EpicurusToday.com to present all information and analysis in plain English. Technical jargon — whether Greek, Latin, or academic philosophical terminology — is to be avoided in favor of clear English equivalents. There is no Greek or Latin term, and no academic philosophical label, that cannot be adequately conveyed in modern language — perhaps not always by a single word, but always by a clear and concise phrase that any careful reader can understand without specialized training.
This principle matters because Epicurean philosophy was itself written in plain language for a broad audience. Epicurus wrote for everyone, not for a professional class of scholars. When modern commentators wrap his ideas in layers of untranslated Greek and Latin, or in the private vocabulary of academic philosophy, they erect an unnecessary barrier between the philosophy and the people it was meant to help. EpicurusToday.com works against that barrier.
This page exists for two purposes: first, as a reference for readers who encounter these terms in outside sources and need to know what they mean; and second, as a reminder to our own contributors that the plain English equivalent should always come first, with the technical term in parentheses when reference is needed.
Entries are arranged alphabetically by their transliterated Greek form. Where a concept is known by both a Greek and a Latin name — such as the atomic swerve, known in Greek as parenklisis and in Latin as clinamen — the entry appears under the Greek transliteration, with the Latin name given in the header and cross-referenced. Where a term originates only in Latin (such as summum bonum), the entry appears under the Latin. Where a term is a modern academic label, its origin and plain English equivalent are explained.
Adiaphora
Section titled “Adiaphora”Transliteration: adiaphora | Greek: ἀδιάφορα | Latin equivalents: indifferentia (Cicero’s standard translation); media (“things in the middle”) | Plain English: indifferents; things that do not matter
The Stoic label for everything that is neither virtue nor vice — including health, wealth, pain, pleasure, life, and death. The Stoics taught that these things are genuinely “indifferent” to the question of living well, since only virtue determines whether a life is good. This is precisely the position Epicurean philosophy rejects from its foundations: Epicurus held that pleasure and pain are nature’s own testimony about what matters, and that health, friendship, and freedom from pain are genuine goods, not indifferent trifles. The Stoic claim that pleasure is an “indifferent” directly contradicts the most basic fact of Epicurean physics — that nature herself provides every living creature with pleasure and pain as guides from the moment of birth.
Aisthēsis
Section titled “Aisthēsis”Transliteration: aisthesis | Greek: αἴσθησις | Latin equivalents: sensus (“sense,” Cicero’s standard); perceptio (“perception”) | Plain English: sensation; sense-perception
The direct report of the senses — what we see, hear, touch, taste, and smell. In Epicurean theory of knowledge (canonics), sensation is the first and foundational criterion of truth. All sensations are true as sensations: what the eye sees is what the eye sees. Error arises not from sensation itself but from the opinions and judgments we add to sensory reports. This is a radical position that Epicurus held deliberately against the Platonic tradition (which regarded sensory knowledge as inferior to rational knowledge) and against the Skeptics (who claimed that the senses are unreliable). For Epicurus, the trustworthiness of sensation is not merely assumed — it is the bedrock on which all knowledge, including knowledge of atoms and void, ultimately rests.
Apeiron
Section titled “Apeiron”Transliteration: apeiron | Greek: ἄπειρον | Latin equivalents: infinitum (“the infinite”); immensum (“the immeasurable”) | Plain English: the Unlimited; the Infinite; the Boundless
The term used by the early philosopher Anaximander for the primary substance of all things — not water, air, or fire, but an undefined, unlimited, eternal substrate from which everything arises and to which everything returns. The term is not part of Epicurean vocabulary; Epicurus identified the primary constituents of reality as atoms and void, both of which are specific and definable. The apeiron is noted here because it represents the kind of vague metaphysical entity — a “something” beyond all sensation and experience — that Epicurean theory of knowledge refuses to accept as genuine knowledge.
Aponia
Section titled “Aponia”Transliteration: aponia | Greek: ἀπονία | Latin equivalents: indolentia (Cicero’s coinage, literally “without pain”); vacuitas doloris (“freedom from pain”) | Plain English: freedom from bodily pain; absence of physical suffering
One of the two forms of complete pleasure recognized in Epicurean ethics — the pleasure of the body when pain has been removed. The companion term for the mind is ataraxia (freedom from mental disturbance). Together they describe the condition Epicurus identified as the limit of pleasure: a life fully free from pain, physical and mental. It is important to understand that Epicurus did not regard aponia as mere neutrality or absence. He held that the removal of pain is itself a genuine and full form of pleasure — not a zero waiting to be filled by something better, but a real positive condition. See also: ataraxia.
Transliteration: arche | Greek: ἀρχή | Latin equivalents: principium (“first principle,” Cicero’s standard); initium (“beginning”); origo (“origin, source”) | Plain English: first principle; primary substance; foundational cause
The term used by early Greek natural philosophers for the fundamental stuff or principle from which everything else arises. Thales said it was water; Anaximenes said it was air; Heraclitus said it was fire. Epicurus’s answer to the arche question was: atoms and void. Everything that exists is either body (made of atoms) or space (void), and there is no third thing. The importance of the arche question for Epicureanism is that getting it right — identifying the actual foundational stuff of the world — is the essential first step toward removing the groundless fears that come from misunderstanding nature.
Ataraxia
Section titled “Ataraxia”Transliteration: ataraxia | Greek: ἀταραξία | Latin equivalents: tranquillitas (Cicero’s standard, “tranquility of mind”); securitas (“freedom from care”); vacuitas animi (“emptiness of the mind from disturbance”) | Plain English: freedom from mental disturbance; peace of mind; tranquility
One of the most persistently misused terms in discussions of Epicurean philosophy. Ataraxia means freedom from mental agitation — the state of mind in which groundless fears, anxious beliefs, and irrational disturbances have been removed by correct understanding of nature. It is a real and important Epicurean concept. However, it is not the goal of Epicurean philosophy, and treating it as the goal is the single most consequential distortion of Epicurus in modern commentary.
The goal, as Epicurus states explicitly and repeatedly, is pleasure (hēdonē) and happiness (eudaimonia). Ataraxia is a feature of the mind that has achieved this goal — it describes what a pleasured, happy mind looks like from the inside — not the destination itself. Substituting ataraxia for pleasure as the Epicurean goal is an ancient distortion, driven largely by Stoic and later religious commentators who were uncomfortable identifying pleasure as the highest good and preferred the more sedate-sounding “tranquility.” EpicurusToday.com works consistently to correct this substitution.
Atomos
Section titled “Atomos”Transliteration: atomos | Greek: ἄτομος | Latin equivalents: individuum (Cicero’s literal translation, “the undivided”); corpus (“body,” used by Lucretius for atomic matter generally) | Plain English: indivisible particle; atom
From the Greek a- (not) and temnō (to cut) — literally “the uncuttable.” The smallest units of matter: solid, internally unchanging, physically indivisible particles that move through void and whose various combinations and arrangements produce everything that exists. The atomic theory was developed by Leucippus and Democritus and adopted and substantially improved by Epicurus. Epicurus’s key addition was the doctrine of minimum parts (elachista) — the recognition that although atoms cannot be physically divided, they have a smallest theoretical spatial extent, which responds to Aristotle’s argument that anything physically extended must be infinitely divisible in theory. See also: elachista.
Autarkeia
Section titled “Autarkeia”Transliteration: autarkeia | Greek: αὐτάρκεια | Latin equivalents: sufficientia (“self-sufficiency”); continentia (“self-containment, restraint”) | Plain English: self-sufficiency; independence from excessive external needs
The condition of needing relatively little from the external world in order to live well. For Epicurus, autarkeia is not an ideal of radical self-denial or isolation — it is the practical result of correctly understanding which desires are natural and necessary (and therefore easily satisfied) versus which are empty desires generated by false beliefs (and therefore insatiable). A person who has reduced their genuine needs to what nature actually requires is in a position of considerable personal freedom: they are not hostage to fortune or dependent on things they cannot control. Autarkeia in this sense supports the pleasurable life rather than limiting it.
Canonics / Kanonika
Section titled “Canonics / Kanonika”Transliteration: kanonika | Greek: κανονική | Latin equivalents: canonica (the borrowed and adapted Latin form used by later writers); regula (“rule, standard”) for the underlying concept | Plain English: the Epicurean theory of knowledge; the study of the standard of truth
One of the three branches of Epicurean philosophy (alongside physics and ethics). The name comes from kanōn — a measuring rod or ruler — which Epicurus used as a metaphor for the standard by which truth is measured. Canonics establishes the three criteria of truth: sensation (aisthēsis), preconceptions (prolēpsis), and feelings of pleasure and pain (pathē). It explains why the senses are reliable, how false judgments arise, and how correct reasoning can distinguish genuine knowledge from empty opinion. Canonics is foundational: both physics (which makes claims about atoms and void that cannot be directly observed) and ethics (which makes claims about what nature provides as guides to life) depend on having a sound account of how knowledge is possible at all. See also: aisthēsis, prolēpsis, pathē.
De Finibus
Section titled “De Finibus”Origin: Latin | Greek equivalents: Peri Telōn (Περὶ Τελῶν, “On Goals / On Ends”); more fully Peri Telōn Agathōn kai Kakōn (Περὶ Τελῶν Ἀγαθῶν καὶ Κακῶν, “On the Goals of Good and Bad Things”) | Plain English: On Ends; On Goals; On the Highest Good
The title of Cicero’s philosophical dialogue in which he presents and critiques the ethical positions of the three major philosophical schools — Epicurean, Stoic, and Academic. For Epicurean philosophy, De Finibus Book I is the single most important surviving source for the systematic presentation of Epicurean ethics, delivered by the spokesman Lucius Manlius Torquatus. Books II contains Cicero’s hostile critique. Despite Cicero’s evident antipathy toward Epicureanism, the care and detail of Torquatus’s presentation in Book I make it an invaluable primary source. “Finis” in the title means the goal or end of life — the question being: what is life ultimately for?
De Rerum Natura
Section titled “De Rerum Natura”Origin: Latin | Greek equivalents: Peri Physeōs (Περὶ Φύσεως, “On Nature”) — the title Epicurus used for his own major work on physics, and the standard Greek title for the whole tradition of natural philosophy writing | Plain English: On the Nature of Things
The title of the great philosophical poem by Lucretius (c. 99–55 BC), written in six books of Latin verse. It is the most complete surviving ancient exposition of Epicurean physics, and one of the most important works in the history of philosophy. Lucretius presents the atomic theory, the void, the nature of the soul, the origin of the world and of life, the explanation of natural phenomena without divine intervention, and the Epicurean case for why the fear of death is groundless. The poem was largely unknown during the medieval period and was rediscovered by the humanist Poggio Bracciolini in 1417 — an event that significantly influenced the development of Renaissance thought.
Dialectic / Dialektikē
Section titled “Dialectic / Dialektikē”Transliteration: dialektike | Greek: διαλεκτική | Latin equivalents: dialectica (borrowed directly); disputatio (“argumentation, debate”); disserendi ratio (Cicero’s phrase, “the method of reasoning”) | Plain English: the art of argument; reasoning by question and answer; philosophical debate
Originally the method of philosophical conversation practiced by Socrates — working through a question by sustained exchange of argument and counter-argument. Later used more broadly to describe the formal art of philosophical reasoning and refutation. The Academic Skeptics, particularly Arcesilaus, were said to be “devoted to dialectic” — meaning they were committed to the method of producing counter-arguments against every position, rather than to establishing positive conclusions. Epicurus was famously impatient with dialectic as an end in itself, regarding it as philosophical game-playing that produced no genuine knowledge and no practical benefit. For Epicurus, the purpose of philosophy was therapeutic — to free people from groundless fears — not to demonstrate virtuosity in argumentation.
Transliteration: doxa | Greek: δόξα | Latin equivalents: opinio (“opinion,” Cicero’s standard); existimatio (“judgment, estimation”) | Plain English: opinion; belief; mere appearance; the realm of seeming
Used in two related senses. In the Platonic tradition, doxa is the inferior form of cognition that grasps only the changing, sensory world of appearances — as opposed to genuine knowledge (epistēmē) of the eternal Forms. Parmenides used it similarly to describe the realm of mortal opinion that must be distinguished from the truth accessible to reason. Epicurus rejected this use of doxa: for him there is no separate realm of eternal truth accessible only to reason that sensation cannot reach. However, Epicurus did use the concept of opinion to explain error: sensation itself is always accurate, but the opinions (doxai) we add to sensory reports can be mistaken, and it is there that error enters. The practical Epicurean project of correcting false beliefs about the gods, death, and the nature of pleasure is a project of replacing bad opinions with good ones.
Eidōla
Section titled “Eidōla”Transliteration: eidola | Greek: εἴδωλα | Latin equivalents: simulacra (Lucretius’s standard term, “likenesses, images”); imagines (“images”); figurae (“figures, shapes”) | Plain English: images; films; atomic films shed from the surfaces of objects
The Epicurean account of how perception works: objects continuously shed extremely thin films of atoms from their surfaces, which travel through the air and enter our sense organs, producing the experience of seeing, hearing, and smelling. These films (eidōla) preserve the shape and appearance of the object they came from. The gods, too, are perceived through eidōla — which is why our natural preconceptions of them take the form they do. The theory is the physical mechanism behind Epicurean epistemology: sensation is reliable because it is a genuine physical contact between the sense organ and material coming directly from the object.
Ekpyrosis
Section titled “Ekpyrosis”Transliteration: ekpyrosis | Greek: ἐκπύρωσις | Latin equivalents: deflagratio (“burning-up, conflagration”); conflagratio mundi (“the burning of the world”) | Plain English: world-conflagration; the periodic burning-up of the universe
The Stoic doctrine that the universe periodically burns away entirely in a great fire — returning everything to pure rational fire (logos) — and is then regenerated anew in a cycle identical to the previous one, down to the last detail. This doctrine is of interest from an Epicurean perspective primarily as an example of what Epicurean physics replaces: a universe governed by a divine rational cycle that determines everything in advance is precisely the kind of providential cosmos Epicurean atomism was designed to refute. The Epicurean universe by contrast has no predetermined cycle, no divine governance, and gives rise to an infinite variety of worlds by the undirected motions of atoms.
Elachista
Section titled “Elachista”Transliteration: elachista | Greek: ἐλάχιστα | Latin equivalents: minima (Lucretius’s term, “the smallest things”); minimae partes (“minimum parts”) | Plain English: minimum parts; the smallest conceivable units of spatial extent within an atom
One of Epicurus’s most technically sophisticated contributions to atomic theory. Democritus held that atoms were physically indivisible but made no systematic claim about their internal structure. Aristotle attacked this by arguing that anything physically extended in space must be theoretically divisible — and that if you allow infinite theoretical divisibility, the concept of a truly indivisible atom is incoherent. Epicurus answered by proposing that atoms contain minimum parts (elachista): the smallest conceivable unit of spatial extension, which cannot be divided even in theory because it represents the absolute limit of spatial smallness. This is not a concession to Aristotle but a refutation: it shows that infinite theoretical divisibility is not forced on us by reason, and that genuine physical and theoretical minima are both conceivable and necessary. This correction effectively saved Democritean atomism from what would otherwise have been a fatal objection.
Empiricism
Section titled “Empiricism”Origin: modern academic philosophy, from Greek empeiria (experience) | Plain English: the view that all genuine knowledge comes from experience and observation
The position, associated in modern philosophy with thinkers like Locke, Hume, and Mill, that knowledge derives from sensory experience rather than from reason operating independently of experience. Epicurean canonics is often described as empiricist in this sense — and the description is broadly correct, though with important qualifications. Epicurus held that sensation is the foundational criterion of truth and that claims about unobservable things (such as atoms) must be anchored in what sensation establishes. However, Epicurus is not a simple empiricist: he also recognizes preconceptions (prolēpseis) as a second criterion of truth, and his account of inference from observable to unobservable is more sophisticated than a simple appeal to “experience.” See also: rationalism.
Epistēmē
Section titled “Epistēmē”Transliteration: episteme | Greek: ἐπιστήμη | Latin equivalents: scientia (“knowledge, science,” Cicero’s standard); cognitio (“knowing, understanding”) | Plain English: genuine knowledge; scientific understanding
In Platonic philosophy, epistēmē is the highest form of knowledge — direct rational grasp of the eternal Forms, as opposed to the mere doxa (opinion) that grasps only sensory appearances. Aristotle used the term for systematic scientific understanding through demonstration from first principles. For Epicurus, the distinction between “genuine knowledge” accessible only to reason and “mere opinion” derived from sensation is false: sensation is itself the criterion of truth, and the Forms that Plato wanted knowledge to grasp do not exist. Epicurus did not use epistēmē in Plato’s exalted sense; for him, reliable knowledge is simply what sensation, correctly interpreted, and preconceptions, correctly applied, establish.
Epochē
Section titled “Epochē”Transliteration: epoche | Greek: ἐποχή | Latin equivalents: suspensio (“suspension”); sustinentia (“holding back”); sustentio iudicii (Cicero’s phrase, “withholding of judgment”) | Plain English: suspension of judgment; withholding assent; refusal to commit to any position
The characteristic move of the Academic and Pyrrhonian Skeptics: when confronted with a question about which arguments on both sides appear equally balanced, the appropriate response is to neither affirm nor deny but to suspend judgment entirely. Arcesilaus and Carneades at the New Academy argued that this suspension should be universal — that no proposition is certain enough to warrant confident assent. Pyrrho went further, suspending judgment on all matters of perception and reasoning alike. Epicurus regarded suspension of judgment as a practical and philosophical catastrophe: it destroys the ability to make confident choices, to pursue pleasure intelligently, and to act on the basis of genuine understanding. The Epicurean response to skeptical suspension of judgment is the reliability of sensation: the senses do not mislead us; it is false opinions about what the senses report that lead us astray.
Ethics
Section titled “Ethics”Origin: Greek ēthos (ἦθος, “character, habit”) | Latin equivalents: moralis (coined by Cicero as a direct translation of ēthikos); moralia (“matters of character and conduct”) | Plain English: the study of how to live well; the branch of philosophy concerned with what makes life good and actions right
One of the three branches of Epicurean philosophy (alongside physics and canonics). Epicurean ethics begins from the natural fact that every living creature pursues pleasure and avoids pain from birth, without being taught — this is nature’s own testimony about what matters. From this foundation, Epicurean ethics works out how to pursue a genuinely pleasurable life wisely across a full human lifetime: how to distinguish natural from empty desires, how to build genuine friendships, how to understand death so as not to fear it, and how to maintain happiness even in difficult circumstances. Ethics without physics is impossible, in the Epicurean view: you cannot know how to live well if you do not know what you are.
Eudaimonia
Section titled “Eudaimonia”Transliteration: eudaimonia | Greek: εὐδαιμονία | Latin equivalents: beatitudo (“blessedness, complete happiness”); felicitas (“happiness, good fortune”); vita beata (Cicero’s phrase, “the blessed life”) | Plain English: happiness; a flourishing life; living well and doing well
The Greek term for the condition of living a genuinely good life — one in which things are going well at the deepest level. All the major philosophical schools agreed that eudaimonia is what philosophy is ultimately supposed to help us achieve; they disagreed entirely about what it consists in. For Aristotle, eudaimonia is activity of the soul in accordance with virtue. For the Stoics, it is the condition of the perfectly virtuous rational agent. For Epicurus, eudaimonia is happiness through pleasure: a life in which pleasures predominate over pains across the full range of experience, grounded in friendship, philosophical understanding, and freedom from groundless fear. The word is sometimes translated “flourishing” or “well-being” to avoid the narrower modern sense of “happiness” as a momentary mood.
Euthymia
Section titled “Euthymia”Transliteration: euthymia | Greek: εὐθυμία | Latin equivalents: hilaritas (Seneca’s term for Democritus’s euthymia, “cheerfulness, good spirits”); laetitia (“joy, gladness”); tranquillitas (though this overlaps with ataraxia) | Plain English: cheerfulness; well-grounded good spirits; equanimity
The term used by Democritus for the goal of life: a stable, well-grounded cheerfulness produced by moderation, self-knowledge, and the avoidance of excessive desire. Democritus did not identify this with pleasure in the full Epicurean sense. Epicurus went further, explicitly identifying pleasure as the goal and providing the physical and ethical framework that explains why and how a pleasurable life is achievable. Euthymia as Democritus used it can be understood as an early approximation to what Epicurus meant by the pleasurable life — pointing in the right direction but not yet fully grounded.
Forms / Eidos / Idea
Section titled “Forms / Eidos / Idea”Transliteration: eidos / idea | Greek: εἶδος / ἰδέα | Latin equivalents: forma (the standard Latin translation, “form, shape”); species (“appearance, kind, type”); imago (“image, likeness”) | Plain English: Platonic Forms; eternal non-material patterns of which sensory things are imperfect copies
Plato’s doctrine that the truly real consists not in the observable, changing world of physical things but in a separate realm of eternal, non-material, unchanging patterns — the Form of Beauty, the Form of Justice, the Form of the Good — of which sensory things are only imperfect, temporary copies. Knowledge, for Plato, is knowledge of the Forms; sensation gives only appearance and opinion. The doctrine of Forms is the principal philosophical target of Epicurean physics and canonics: Epicurus held that there is no such separate realm, that the sensory world is the only real world, and that claims about eternal non-material entities have no support from sensation or experience and therefore constitute empty belief rather than genuine knowledge.
Gnomon
Section titled “Gnomon”Origin: Greek gnōmōn (γνώμων, “one who knows; indicator”) | Latin equivalents: gnomon (the same word adopted directly into Latin); horologium (the more general Latin term for a sundial or time-measuring device) | Plain English: the upright pointer of a sundial; the pin or rod whose shadow indicates the time
A technical instrument of ancient astronomy and geometry: the upright post or pin whose shadow, cast by the sun, allows the measurement of time, latitude, and the height of celestial objects. Anaximander is credited with introducing the gnomon into Greece. The term appears in histories of ancient science and philosophy. It is included here as an example of a technical term that is routinely left untranslated in academic writing when “sundial pointer” or simply “the upright pin of a sundial” conveys the meaning entirely adequately.
Hēdonē
Section titled “Hēdonē”Transliteration: hedone | Greek: ἡδονή | Latin equivalents: voluptas (Cicero’s standard; the word Epicureans used in Latin and that critics used against them); delectatio (“delight, enjoyment”); gaudium (“joy”) | Plain English: pleasure; the enjoyment that living creatures naturally seek
The Greek term for pleasure — the fundamental good in Epicurean ethics. From hēdonē comes the English word “hedonism,” which unfortunately carries connotations of crude sensual excess that Epicurus would have rejected. Epicurean pleasure is not the frantic pursuit of every sensation but the intelligent management of a life in which pleasures predominate over pains, natural desires are satisfied, and groundless fears have been removed. The full Epicurean account distinguishes pleasures of the body from pleasures of the mind (the latter being generally more significant because the mind can encompass past and future), and kinetic pleasures (pleasures of active enjoyment) from the stable pleasure of painlessness (which is itself a complete and genuine form of pleasure). See also: ataraxia, aponia.
Idealism
Section titled “Idealism”Origin: modern academic philosophy | Plain English: the philosophical view that reality is in some fundamental sense mental, abstract, or constituted by mind rather than matter
The family of positions — including Platonic idealism, Berkeleyan idealism, Kantian idealism, Hegelian idealism, and modern variants — that hold that the ultimate nature of reality is not material but mental, abstract, or constructed by consciousness. These positions are the direct descendants of Plato’s doctrine of Forms and share the common feature of treating the observable, sensory world as less real than something non-material that underlies or constitutes it. Epicurean physics and canonics are a systematic refutation of idealism in all its forms: the world experienced through sensation is the only real world, matter is not constituted by ideas or categories or rational structures, and claims about non-material realities that transcend observation are empty.
Kathêkon
Section titled “Kathêkon”Transliteration: kathekon | Greek: καθῆκον | Latin equivalents: officium (Cicero’s standard translation, “duty, obligation”); munus (“function, duty, service”) | Plain English: appropriate action; fitting conduct; duty (in the Stoic sense)
The Stoic term for the class of actions that are “appropriate” or “fitting” for a rational being to perform — roughly equivalent to moral duty. Panaetius’s influential treatise on to kathêkon was the model for Cicero’s De Officiis (“On Duties”), one of the most widely read philosophical works in Western history and a significant vehicle for Stoic ethics in the Roman and later Christian traditions. The Epicurean position on duty is entirely different: actions are to be evaluated by their contribution to the pleasurable life, not by their conformity to an abstract standard of rational fitness. The concept of duty as a binding obligation independent of pleasure is precisely the kind of empty philosophical construction that Epicurean ethics replaces with the natural evidence of pleasure and pain.
Kenē Orgē
Section titled “Kenē Orgē”Transliteration: kene orge | Greek: κενὴ ὀργή | Latin equivalents: inanis ira (“empty/vain anger”); vana iracundia (“groundless rage”) | Plain English: empty anger; anger not grounded in real harm
The first of three types of anger that Philodemus distinguishes in his work On Anger (Peri Orgēs) and the only type the Epicurean sage will never experience. Empty anger arises from false beliefs — imagining that the universe owes you smooth treatment, taking pleasure in fantasies of revenge for their own sake, or responding to accidents, bad luck, and impersonal events as though they were personal offenses. It is called “empty” because it tracks nothing real: there is no genuine harm done, no agent who acted intentionally against your interests, nothing that would justify anger if the underlying beliefs were corrected. Contrast with natural anger (orgē physikē), which Philodemus declares inescapable and appropriate when genuine intentional harm has been done.
Transliteration: kenon | Greek: κενόν | Latin equivalents: inane (Lucretius’s standard term, “the empty”); vacuum (“empty space,” used by later Latin writers); locus (“place, space”) | Plain English: void; empty space; the absence of matter
One of the two fundamental constituents of reality in Epicurean physics (the other being atoms). Void is not nothing — it is the real condition of empty space that makes motion possible. Without void, atoms would have nowhere to move, and without motion there would be no combinations, no worlds, no living things. Aristotle denied the existence of void, arguing that empty space is a contradiction in terms. Epicurus rejected this argument: motion is real, and motion requires that there be somewhere to move into. The reality of void is one of the foundational claims of Epicurean physics, established by the plain evidence that motion occurs.
Kinēsis
Section titled “Kinēsis”Transliteration: kinesis | Greek: κίνησις | Latin equivalents: motus (the standard Latin term, “motion, movement”); mutatio (“change, alteration”) | Plain English: motion; movement; change
Motion is one of the fundamental realities of Epicurean physics and one of the key issues in the debate between atomism and its critics. Aristotle argued extensively about the nature of motion in his Physics, raising problems about continuity, contact, and infinite divisibility that were specifically directed at atomic theory. Epicurus accepted some of the conclusions these arguments forced — including the quantization of atomic motion through minimum parts (elachista) — while rejecting Aristotle’s overall conclusion that the void and atoms are impossible. In Epicurean physics, the eternal motion of atoms through void is the foundational process from which everything else arises.
Transliteration: logos | Greek: λόγος | Latin equivalents: ratio (Cicero’s most common translation, “reason, rational principle”); verbum (“word,” used in the Johannine tradition); oratio (“speech, discourse”) | Plain English: reason; rational order; the governing rational principle (in Stoic use); also: word, account, argument
One of the most important and most overloaded terms in ancient Greek philosophy. In Heraclitus, logos is the rational principle governing the universe that most people fail to perceive. In Stoicism, logos is the divine rational order that pervades and governs all things — identified with God, with fire, and with fate. In common usage it simply means word, speech, or account. The Stoic logos is precisely the kind of divine governance of nature that Epicurean physics is constructed to replace: Epicurus demonstrated that the order of the world arises from the natural motions of atoms without any directing rational intelligence. The word’s English descendant appears in “-ology” suffixes (biology, theology, etc.) — literally “the account of” whatever the field concerns.
Materialism
Section titled “Materialism”Origin: modern academic philosophy | Plain English: the view that only matter (and its properties and relations) exists; that there is nothing non-material
The philosophical position that everything that exists is material — that there are no non-material souls, no non-material divine beings, no non-material Platonic Forms, no non-material rational order governing the cosmos. Epicurean physics is materialist in this sense: atoms and void are the only fundamental constituents of reality, and everything — including souls, minds, gods, and the movements of the heavens — is to be explained by material causes. However, Epicurean materialism should not be confused with the eliminative materialism or reductionism of some modern forms: Epicurus was not trying to reduce love, friendship, or pleasure to mere atomic motion. He was affirming that these real human experiences have real material explanations, not supernatural ones.
Meletē
Section titled “Meletē”Transliteration: melete | Greek: μελέτη | Latin equivalents: meditatio (“practice, exercise of the mind” — giving us the English “meditation”); exercitatio (“practice, training, exercise”); studium (“devoted study, application”) | Plain English: practice; study; repeated exercise of the mind on a subject
The word means simply practice or study — the repeated, deliberate engagement with something in order to master it or keep it present. A musician practices scales; a soldier practices drills; a philosopher practices the arguments and conclusions that will sustain clear thinking when it matters. Meletē in Epicurean use is this kind of practical, habitual engagement with philosophical ideas — reading them again, turning them over, testing them against experience — so that correct understanding becomes second nature rather than a position one has to reconstruct from scratch in every difficult moment.
The word becomes interesting — and the source of some confusion — in two specific contexts. The first is the Socratic phrase melete thanatou (μελέτη θανάτου), “practice of dying,” which appears in Plato’s Phaedo and describes Socrates’ view of the philosophical life as a sustained preparation for death by detaching the soul from the body. Epicurus addressed this idea directly and rejected its premise: the correct response to death is not lifelong contemplative preparation but the straightforward understanding that death is simply the dispersal of atoms, after which there is no subject to experience anything. You do not need a lifetime of practice to accept a simple truth. The Socratic melete thanatou is based on a false picture of what death is; once that picture is corrected, the “practice” it calls for becomes unnecessary. For Epicurus, what is needed is not prolonged preparation but correct understanding, applied once and refreshed as needed.
The second source of confusion is the English rendering “meditation.” This translation is not wrong, but in contemporary usage the word “meditation” has been heavily colonized by Buddhist-influenced mindfulness practice, Stoic journaling exercises, and various forms of structured introspection that carry specific technical meanings remote from the plain Greek sense of the word. When modern commentators translate meletē as “meditation” without further explanation, they risk importing an entire framework of associations — quietism, inwardness, withdrawal from ordinary engagement — that is foreign to what the word actually means and actively misleading about the Epicurean use of it. Epicurean meletē is not a spiritual practice and not a technique; it is simply the habit of keeping useful ideas present to mind through regular engagement. “Practice” or “study” conveys this without the baggage.
This entry is itself an illustration of the broader point this guide makes: “meditation” is a word that sounds technical and profound, which is precisely why it gets used in translations where “practice” or “study” would serve better. The jargon serves the translator’s purposes — it makes the subject sound more exotic and the translator more learned — rather than the reader’s need for clarity.
Epicurean relationship: The concept is genuinely Epicurean in a practical sense, even if the word itself does not appear as prominently in surviving Epicurean texts as in Platonic ones. The Letter to Menoeceus closes with the instruction to “practice these things and the things akin to them” — using melete in exactly this plain, practical sense. The Epicurean community in the Garden was built around this kind of regular, shared engagement with philosophical ideas. The tetrapharmakos itself is a compressed aid to meletē: four things to keep present to mind, not as objects of mystical contemplation but as plain truths to be remembered and applied.
Metempsychosis
Section titled “Metempsychosis”Transliteration: metempsychosis | Greek: μετεμψύχωσις | Latin equivalents: transmigration animorum (“migration of souls,” the standard Latin phrase); metempsychosis (borrowed directly into Latin by later writers) | Plain English: transmigration of souls; reincarnation; the belief that the soul passes from one body to another after death
The Pythagorean and Platonic doctrine that the soul survives the death of the body and is reborn into a new body — human, animal, or divine — according to the quality of the life it has lived. This doctrine was also held by Empedocles. It stands in direct opposition to the Epicurean demonstration that the soul is a material compound of atoms that disperses at death, leaving no surviving subject to experience any subsequent condition. Epicurus regarded the fear of post-mortem punishment and the hope of post-mortem reward — including through reincarnation — as major sources of the groundless anxiety that philosophy is designed to cure.
Metaphysics
Section titled “Metaphysics”Origin: academic label, from the title of Aristotle’s work ta meta ta physika (the things after the physics) | Plain English: the branch of philosophy concerned with the fundamental nature of reality; what ultimately exists and what it is
Originally a label for the set of Aristotle’s writings collected after his works on natural science (Physics). It came to mean the branch of philosophy that investigates the most basic questions about existence: What kinds of things are real? What makes something the kind of thing it is? Is there a God? Does the soul exist? What is the relationship between mind and matter? Epicurean physics addresses the core questions of metaphysics — what exists, what it is made of, how it is structured — through the atomic theory: everything is atoms and void, everything arises from natural causes, and there is no supernatural realm.
Naturalism
Section titled “Naturalism”Origin: modern academic philosophy | Plain English: the view that everything can and should be explained by natural causes, without appealing to supernatural agents or forces
The philosophical commitment to explaining all phenomena — including the origin of the world, the development of life, the nature of mind, and the source of moral knowledge — by natural processes, without invoking gods, spirits, divine providence, or supernatural forces. Epicurean physics is naturalistic through and through: the world arises from atoms and void; the gods exist but play no role in natural processes; and everything from the formation of worlds to the origin of human societies can be explained without supernatural intervention. Epicurus was not the only ancient naturalist, but his was the most systematic and complete ancient naturalist philosophy.
Transliteration: nous | Greek: νοῦς | Latin equivalents: mens (Cicero’s standard, “mind, intellect”); intellectus (“understanding, intellect”); animus (“mind, spirit” in a broader sense) | Plain English: mind; intelligence; the organizing intellect
Used in two importantly different senses. In Anaxagoras, nous is the non-material organizing intelligence that imposed order on the original chaotic mixture of matter and set it in motion — not a personal creator, but a rational ordering principle. In Aristotle, nous is the highest faculty of the human soul — pure rational intuition — as well as the unmoved mover’s eternal self-thinking thought. In both cases, nous is used to introduce a non-material rational principle into explanations of nature, which is precisely what Epicurean physics replaces with the natural motions of atoms. Epicurus argued that the order of the world does not require a directing intelligence; it arises from the natural properties of atoms moving through void.
Ontology
Section titled “Ontology”Origin: modern academic philosophy, from Greek ontos (being) and logos (account) | Plain English: the study of what exists; the branch of philosophy concerned with the nature and categories of being
The philosophical inquiry into what kinds of things exist, how they exist, and what it means for something to be real. The central ontological question for ancient physics was: what are the basic constituents of reality? Epicurus’s answer — atoms and void — is as clear an ontological position as has ever been stated: everything that exists is either body or space, and there is no third thing. This parsimony is one of the great strengths of Epicurean physics: it accounts for the full diversity of the observable world with the smallest possible ontological commitment.
Transliteration: pathe | Greek: πάθη | Latin equivalents: affectus (Cicero’s standard, “feelings, affections”); perturbationes (Cicero’s other rendering, “disturbances” — though this reflects a Stoic bias by implying feelings are disruptions); motus animi (“movements of the mind”) | Plain English: feelings; emotions; the affective states of pleasure and pain
In Epicurean theory of knowledge, the pathē — feelings of pleasure and pain — are the third criterion of truth alongside sensation (aisthēsis) and preconceptions (prolēpsis). They are the foundational guides to action: what feels pleasant is to be pursued; what feels painful is to be avoided. This is not a subjective preference but a natural fact: nature herself provides pleasure and pain as the universal indicators of what promotes and what harms the life of any living creature. The practical application of the pathē as a criterion of truth is the ability to distinguish genuine natural pleasures from empty pleasures generated by false beliefs. See also: aisthēsis, prolēpsis.
Parenklisis / Clinamen
Section titled “Parenklisis / Clinamen”Transliteration: parenklisis | Greek: παρέγκλισις | Latin equivalent: clinamen (Lucretius’s term in De Rerum Natura; the word he coined for exactly this concept); also declinatio (“deflection, deviation”) | Plain English: the atomic swerve; the spontaneous, uncaused slight deviation in an atom’s path
The Epicurean term for the small, spontaneous deviation that an atom occasionally makes from its path through the void — a deviation that is not caused by any prior condition and that therefore introduces genuine indeterminacy into an otherwise fully determined physical system. The swerve is Epicurus’s deliberate correction of Democritus’s strict determinism. Without it, atoms falling through void in parallel paths would never collide, no worlds could form, and everything in the universe would be the necessary outcome of prior causes — leaving no room for genuine human freedom of choice. The swerve solves both problems: it explains how worlds form without external causation, and it provides the physical basis for free will. Lucretius coined the Latin clinamen specifically to render Epicurus’s parenklisis in his poem De Rerum Natura; the two terms refer to exactly the same concept. See also: atomos, kenon.
Peripatoi
Section titled “Peripatoi”Transliteration: peripatoi | Greek: περίπατοι | Latin equivalents: ambulationes (“walkways, places for walking”); porticus (“covered colonnade”) — though Latin writers most often simply borrowed the Greek term directly | Plain English: covered walkways; shaded colonnades for walking
The covered walkways of the Lyceum, the gymnasium in Athens where Aristotle taught. He delivered his lectures while walking with his students in these walkways, and from this practice his school took the name Peripatetic. The term is sometimes left untranslated in discussions of ancient philosophy as though it were a philosophical technical term; it is not — it simply describes where Aristotle taught.
Philosophos
Section titled “Philosophos”Transliteration: philosophos | Greek: φιλόσοφος | Latin equivalents: philosophus (borrowed directly and universally used); sapientiae studiosus (Cicero’s literal translation, “one devoted to wisdom”) | Plain English: lover of wisdom; one who pursues wisdom
From phileō (to love) and sophia (wisdom). The word was reportedly first used by Pythagoras to describe those who pursue wisdom rather than claiming to possess it. It is the direct ancestor of our word “philosopher.” It appears here as a reminder that the word has a plain English equivalent — and that the ideal it describes, the person who loves and actively pursues genuine understanding, is exactly what Epicurus aimed to produce and what Epicurean philosophy is designed to help anyone become.
Physics / Physika
Section titled “Physics / Physika”Origin: Greek physika (φυσικά, “things relating to nature”), from physis (φύσις, “nature”) | Latin equivalents: physica (borrowed directly); rerum natura (“the nature of things,” Lucretius’s phrase); naturalis philosophia (“natural philosophy”) | Plain English: the study of nature; natural philosophy; the investigation of what the world is made of and how it works
One of the three branches of Epicurean philosophy (alongside canonics and ethics). For Epicurus, physics is not merely academic: understanding the nature of things is essential to living well. The primary practical purposes of Epicurean physics are: to demonstrate that the world arose without divine design and continues without divine governance (removing the fear of divine punishment); to demonstrate that the soul is mortal and disperses at death (removing the fear of post-mortem suffering); and to show that natural phenomena like lightning and earthquakes have natural causes (removing the fear that they are divine warnings). Physics liberates. See also: atomos, kenon, parenklisis.
Phronēsis
Section titled “Phronēsis”Transliteration: phronesis | Greek: φρόνησις | Latin equivalents: prudentia (Cicero’s standard, giving us the English “prudence”); sapientia (“wisdom” — though this more often translates sophia); consilium (“sound judgment, practical counsel”) | Plain English: practical wisdom; the ability to reason well about how to live
The ability to judge correctly in practical matters — to know what genuinely promotes the good life and to act accordingly. For Aristotle, phronēsis is the master virtue that coordinates all the others. For Epicurus, practical wisdom is the most important tool in the pursuit of the pleasurable life: the ability to distinguish natural from empty desires, to calculate which pleasures lead to greater pains and which to sustained happiness, to manage fear and anxiety, and to build and maintain genuine friendships. Epicurus called it the source and root of all the virtues — not because virtue is the goal, but because wisdom is what makes pleasure achievable and sustainable across a life.
Pneuma
Section titled “Pneuma”Transliteration: pneuma | Greek: πνεῦμα | Latin equivalents: spiritus (the standard Latin equivalent, giving us “spirit”); anima (“breath, vital spirit, soul”); flatus (“breath, breeze”) | Plain English: breath; vital spirit; the material medium of rational order (in Stoic use)
In Stoic physics, pneuma is a fine material substance — a mixture of fire and air — that pervades all things and serves as the medium through which the divine rational order (logos) organizes and animates the world. Different degrees of tension in the pneuma account for the different properties of different things: stones, plants, animals, and rational beings all have different grades of pneuma. The soul, for the Stoics, is pneuma of the highest tension. Epicurean physics has no equivalent: the soul for Epicurus is a compound of very fine atoms, and the governing role assigned to pneuma in Stoic physics reflects the divine governance of nature that Epicurean atomism is designed to replace.
Prolēpsis
Section titled “Prolēpsis”Transliteration: prolepsis | Greek: πρόληψις | Latin equivalents: anticipatio (Cicero’s coinage, “anticipation, pre-conception”); praenotio (another of Cicero’s attempts, “prior notion”); communis notitia (“common notion, shared concept”) | Plain English: preconception; natural anticipation; a general concept formed by repeated experience
The second of the three Epicurean criteria of truth (alongside sensation and feelings). Prolēpseis are the generalized concepts formed in the mind through repeated sensory experience: the concept of “horse,” formed through seeing many horses; the concept of “justice,” formed through repeated social experience; the concept of “god,” formed through the universal experience of perceiving the divine. Preconceptions are natural and reliable — they represent what experience has genuinely established about the common features of a class of things. False beliefs arise when we make judgments that go beyond what preconceptions and sensations actually support. The preconception of the gods, for example, establishes that they exist as supremely blessed beings; the false opinion that they intervene in human affairs is an addition not supported by the preconception itself.
Rationalism
Section titled “Rationalism”Origin: modern academic philosophy | Plain English: the view that genuine knowledge comes from reason operating independently of sensory experience
The position, associated in modern philosophy with Descartes, Spinoza, and Leibniz, that the most important and reliable knowledge is accessible to reason alone — independent of what the senses report. In ancient philosophy, the rationalist tradition runs from Parmenides (who argued that reason reveals unchanging being while the senses show only illusion) through Plato (who held that knowledge of the Forms is accessible only to pure intellect) to the Stoics (who held that the rational order of the universe is what divine reason grasps). Democritus was himself a partial rationalist, holding that rational knowledge of atoms was superior to sensory knowledge of appearances. Epicurus rejected rationalism: sensation is the foundational criterion of truth, and reason serves to interpret sensation rather than to transcend it. See also: empiricism.
Scholarch / Scholarchos
Section titled “Scholarch / Scholarchos”Transliteration: scholarchos | Greek: σχολάρχης | Latin equivalents: scholae princeps (“head of the school”); rector scholae (“director of the school”) — Latin writers most often simply used the borrowed Greek term | Plain English: the head of a philosophical school; the director of an ancient academy
The formal title for the leader and director of one of the major philosophical schools in Athens — the Academy (Platonic), the Lyceum (Peripatetic), the Stoa (Stoic), and the Garden (Epicurean). The succession of scholarchs was important for the institutional continuity of each school. For example, Arcesilaus became the sixth scholarch of the Academy in 264 BC, six years after the death of Epicurus. The Epicurean school had a continuous succession of scholarchs from Epicurus himself through Hermarchus, Polystratus, and others. The term is entirely replaceable by “head of the school” in any modern discussion.
Skeptikoi / Skepticism
Section titled “Skeptikoi / Skepticism”Transliteration: skeptikoi | Greek: σκεπτικοί | Latin equivalents: sceptici (borrowed directly); dubitantes (“those who doubt”); quaerentes (“those who inquire”) — Cicero also used Academici since Roman skepticism was associated with the Academy | Plain English: those who examine; philosophical doubters; those who suspend judgment on all questions
From skeptomai — to look, examine, or consider. The ancient Skeptics, in both their Academic and Pyrrhonian forms, held that no judgment can be made with genuine certainty, and that the appropriate response to every question is suspension of judgment (epochē) rather than confident assertion. Epicurean canonics was developed partly in direct opposition to Skepticism: Epicurus held that the senses are reliable, that genuine knowledge is possible, and that the therapeutic project of philosophy — freeing people from groundless fears — requires confident positive knowledge of how nature actually works. A philosopher who claims to know nothing cannot tell you why death is not to be feared; the Epicurean project requires genuine knowledge, and Epicurus was willing to claim it.
Sophistēs
Section titled “Sophistēs”Transliteration: sophistes | Greek: σοφιστής | Latin equivalents: sophista (borrowed directly); sapientiae simulator (Cicero’s dismissive phrase, “pretender to wisdom”) | Plain English: sophist; a professional teacher of argument and rhetoric who charged fees
In fifth-century Athens, the Sophists were a group of professional teachers — including Protagoras, Gorgias, and Hippias — who charged fees for instruction in rhetoric, argument, and civic skills. They were controversial both because of their fee-charging (seen by many as degrading wisdom to a commodity) and because of the content of some of their teaching, which was perceived as relativistic or morally subversive. Socrates distinguished himself from the Sophists by refusing to charge fees and by claiming genuine philosophical ignorance rather than professional expertise. The modern word “sophisticated” — meaning subtle and worldly — derives from the same root, reflecting the ancient association of the Sophists with cleverness and rhetorical skill.
Stoa / Stoicism
Section titled “Stoa / Stoicism”Transliteration: stoa | Greek: στοά | Latin equivalents: porticus (the Latin architectural equivalent, “covered colonnade”); Stoici (the standard Latin name for adherents of the school, borrowed from Greek) | Plain English: the Painted Porch; the covered colonnade in Athens where Zeno taught; the philosophical school that took its name from it
Stoa means a covered porch or colonnade. The school of philosophy known as Stoicism takes its name from the Stoa Poikilē — the Painted Porch — a public building in Athens decorated with famous murals, where Zeno of Citium established his school around 300 BC. The Stoic and Epicurean schools were the two dominant philosophical movements of the Hellenistic and Roman world, and they were in direct and conscious opposition on virtually every significant question — on physics, on the nature of the gods, on the role of pleasure and pain, on the purpose of the emotions, and on what makes a life genuinely good. See also: adiaphora, logos, ekpyrosis, kathêkon.
Summum Bonum
Section titled “Summum Bonum”Origin: Latin | Greek equivalents: to ariston (τὸ ἄριστον, “the best thing”); to telos (τὸ τέλος, “the goal, the end”); to agathon (τὸ ἀγαθόν, “the good”) — Cicero’s De Finibus is explicitly framed as a discussion of peri telōn | Plain English: the highest good; the ultimate goal of human life
The Latin phrase used by Roman philosophers — especially Cicero — for the supreme object of human pursuit: the thing that is good for its own sake and to which all other goods are instrumental. The central question of ancient ethics was what the summum bonum actually is. For Plato and Aristotle, it is some form of virtuous activity or contemplation. For the Stoics, it is virtue alone. For Epicurus, it is pleasure (hēdonē) — and by extension the happy life (eudaimonia) in which pleasures predominate. Cicero, in his De Finibus, presents and critiques the Epicurean position at length, arguing (unconvincingly, from an Epicurean perspective) that pleasure cannot serve as the summum bonum.
Teleology
Section titled “Teleology”Origin: modern academic label, from Greek telos (goal, end) and logos (account) | Plain English: goal-directedness; the view that natural things have built-in purposes; explaining things by reference to their ends or goals
The explanatory approach associated with Aristotle, in which natural things are understood by reference to their purposes or ends: the eye exists for seeing, the heart for pumping blood, the acorn for becoming an oak tree. Aristotle’s nature is thoroughly goal-directed (teleological): everything in nature tends toward its proper end, and understanding a thing fully requires understanding not only what it is made of and how it came to be but what it is for. Epicurean physics rejects this approach entirely: the world and everything in it arose from the undirected motions of atoms through void. Eyes did not arise because seeing is their purpose; they arose because certain atomic combinations happened to produce the capacity for sight, and creatures with that capacity survived. Epicurus was in this respect closer to Darwinian natural selection than to Aristotle.
Transliteration: telos | Greek: τέλος | Latin equivalents: finis (Cicero’s standard, giving us “De Finibus” — “On Ends”); extremum (“the ultimate point”); scopus (“goal, target,” borrowed from Greek) | Plain English: goal; end; the ultimate purpose of something
The telos of Epicurean philosophy is pleasure (hēdonē) — the natural beginning and end of the good life, as Epicurus states in the Letter to Menoeceus. The concept of telos is important because it orients the entire ethical discussion: once you have identified the telos correctly, all other questions (how to live, what to pursue, what to avoid) become questions about how most effectively to reach that goal. Identifying the telos incorrectly — as virtue (Aristotle), as virtue alone (Stoics), or as ataraxia (misreadings of Epicurus) — sends all subsequent ethical reasoning in the wrong direction. See also: eudaimonia, hēdonē.
Tetrapharmakos
Section titled “Tetrapharmakos”Transliteration: tetrapharmakos | Greek: τετραφάρμακος | Latin equivalents: quadripartita cura (“the four-part cure”); quadruplex remedium (“the fourfold remedy”) — no single standard Latin term exists; the concept was generally cited in Greek even by Latin writers | Plain English: the four-part remedy; the four core teachings of Epicurean philosophy presented as a cure for the soul’s deepest fears
From tetra- (four) and pharmakon (medicine, remedy). The famous four-line summary of the most important practical conclusions of Epicurean philosophy, preserved in the Vatican Sayings and in Philodemus: “Do not fear god; do not fear death; what is good is easy to get; what is terrible is easy to endure.” The tetrapharmakos is the Epicurean therapeutic program in compressed form, corresponding to the four great sources of groundless human suffering: fear of divine punishment, fear of death, anxiety that the requirements of a good life are unachievable, and despair in the face of pain. Epicurean philosophy is medicine for these fears: it demonstrates that the gods do not punish us, that death is simply non-existence, that nature’s genuine requirements are easily met, and that even severe pain either ends quickly or can be managed with the resources philosophy provides.
Transliteration: tyche | Greek: τύχη | Latin equivalents: fortuna (the standard Latin equivalent, giving us “fortune” and “fortunate”); casus (“chance, accident, what falls out”); fors (“chance, luck”) | Plain English: chance; fortune; luck; the unpredictable outcomes of events
The Greek personification of fortune or chance, and a philosophical concept for the role of undetermined outcomes in human life. In Democritus, tyche (chance) is the first cause of all things — contrasting with the nous (intelligence) of Anaxagoras. For Epicurus, the proper response to the role of chance in life is not anxiety but wisdom: the wise person builds a life on the reliable foundations of philosophy, friendship, and correct understanding of what matters, so that chance — whether favorable or unfavorable — cannot overturn their fundamental happiness. The famous Epicurean saying is that “I have anticipated you, Fortune, and I have blocked every entrance you might have used to enter” — meaning that correct understanding removes the grip of fortune over one’s inner life, even when it cannot control external events.
This guide was prepared through ClaudeAI under the editorial supervision of Cassius Amicus. last updated May 1, 2026. It is intended as a reference companion to the ancient texts and to the analytical resources at EpicurusToday.com. Readers who wish to explore the primary sources will find the relevant texts discussed throughout the site, with cross-references to the analyses in the Physics, Canonics, and Ethics sections. Please report any suggestions for corrections or additions to Cassius at EpicureanFriends.com. Entries will be added as new terms arise in the work of EpicureanFriends.com. If you encounter a technical term in a source on Epicurean philosophy that is not covered here, please raise it in the EpicureanFriends.com forum and we will consider adding it.