The Principal Doctrines—Greek Kuriai Doxai, also rendered as Principal Beliefs—are forty compact maxims transmitted at the end of Book 10 of Diogenes Laertius' Lives of Eminent Philosophers. Diogenes wrote centuries after Epicurus, probably in the third century CE. The collection appears to excerpt writings of Epicurus and, in some cases, close associates; it is not a modern “book” with a secure publication date and single continuous argument.
The maxims were designed to make central Epicurean positions memorable. They address the gods and death, pleasure and pain, desire, knowledge, friendship, security, and justice. Their brevity assumes a philosophical school, related letters, and explanatory practice that is absent for most people encountering the text today.
For that reason, read them as a preserved teaching collection rather than forty standalone quotations. Translation and sequence matter, and apparent simplicity can conceal a technical claim.
Pleasure is not endless stimulation
Epicureanism is often caricatured as luxurious indulgence. The doctrines instead connect the limit of pleasure with the removal of bodily pain and mental disturbance. Once a need is satisfied, multiplying intensity does not produce an unlimited good. Prudence matters because some immediately pleasant choices create greater later trouble, while some discomforts support a more stable life.
This is still a theory of pleasure as the good, not modern asceticism. Food, friendship, bodily ease, safety, and freedom from fear have positive importance. The correction is aimed at limitless appetite and confused prediction, not at enjoyment itself.
The terms often translated as freedom from disturbance and absence of bodily pain belong to an ancient ethical and physical system. They should not be converted into a promise of permanent calm or a clinical claim about pain. Chronic pain, illness, trauma, and poverty cannot be reasoned away by redefining the good.
Desires need different questions
The collection distinguishes desires that are natural and necessary, natural but not necessary, and neither natural nor necessary. The categories are a tool for examining dependence, cost, and sufficiency; they are not self-evident labels.
Take one recurring desire and ask:
- What bodily, relational, or practical need sits beneath it?
- How much is enough for that need?
- Does satisfying it reduce disturbance or create a new cycle of maintenance?
- Is the desire strengthened mainly by comparison, prestige, or fear?
- What would happen if I delayed it for one week?
Suppose the object is a new phone. Reliable communication may be a natural practical need. A functioning current device may already satisfy it. A specific upgrade could still be worthwhile for accessibility, work, security, or repair cost; the philosophy does not know those facts in advance. The audit exposes the reason rather than imposing a minimalist verdict.
Gollius's values and choices guide can add duties and relationships that a private desire inventory might miss.
Death and fear require context
Epicurus argues that death is not an experience suffered by the person who has died: while we exist, death is not present; when death is present, we no longer exist. The argument aims to remove a fear that poisons the time available for living.
It does not follow that dying, bereavement, danger, or preventable death are unimportant. Fear can motivate protection, grief responds to a lost relationship, and public health depends on treating life and bodily safety as consequential. The maxim addresses the imagined posthumous state of the deceased, not every emotion and obligation surrounding mortality.
For someone in acute grief or severe health anxiety, philosophical argument may be unwelcome or insufficient. It should not be imposed as a correction. Appropriate human and professional support takes priority over winning a metaphysical point.
Justice is an agreement with conditions
The later doctrines describe justice in terms of mutual advantage: arrangements not to harm or be harmed. They also allow that what counts as just can vary when circumstances change and an arrangement no longer serves that mutual benefit.
This is more social than the stereotype of Epicurean retreat suggests. Security depends on trustworthy relations, and friendship is treated as a major resource of a good life. Yet a mutual-advantage account raises questions about people who cannot bargain as equals and about rights that should not disappear when they inconvenience the powerful.
A modern application should not use “agreement” to legitimize coercion. Consent, legal rights, care for vulnerable people, and institutional accountability require frameworks developed far beyond the maxims. The doctrines can prompt examination of whether a rule still prevents harm; they cannot decide a contemporary legal or political dispute by themselves.
Knowledge protects choice
Several doctrines warn against rejecting perception wholesale and against forming judgments without adequate confirmation. Epicurean epistemology is more complex than “trust your senses,” but the practical direction is recognizable: choices about pleasure and fear depend on an accurate account of causes and consequences.
Before renouncing or pursuing something, distinguish observation, expectation, and inherited story. “I spend two hours a night on this app” is an observation; “it is the only way I can relax” is a hypothesis; “successful people are always reachable” may be a social script. Test the hypothesis without pretending one experiment settles a life.
The site's guide to critical thinking is a useful modern companion because it adds source evaluation and uncertainty.
Transmission and translation cautions
Diogenes Laertius is our principal literary source for these doctrines, but he is late. Other Epicurean texts survive in fragments, papyri, inscriptions, hostile reports, and partially overlapping collections such as the Vatican Sayings. Scholars reconstruct the system by comparing this uneven evidence.
English choices can change the tone: “beliefs” or “doctrines,” “tranquility” or “freedom from disturbance,” “justice” or “the just,” “natural” and “necessary.” Read a numbered maxim in more than one translation and consult commentary before extracting a rule. Do not attribute every polished internet sentence to Epicurus without a source location.
A practical reading sequence
Choose one cluster rather than reading all forty as commandments: fear and death, desire and pleasure, or justice and friendship. For each maxim, write its claim, the problem it seems designed to solve, one situation where it clarifies choice, and one modern case it does not adequately address.
Then make one low-risk experiment. Delay a status purchase, share a simple meal with a friend, remove one recurring source of needless comparison, or review whether a rule still prevents mutual harm. Judge the experiment by sufficiency, relationship quality, and downstream cost—not by how “Epicurean” it appears.
The Principal Doctrines offer a rigorous challenge to unlimited desire and superstitious fear. Their best contemporary use is not a lifestyle aesthetic. It is the disciplined question of what is enough, which pleasures remain stable, and how security depends on knowledge, friendship, and just relations.
Text and sources
The forty doctrines and their location in Book 10 were checked against the Perseus Digital Library text of Diogenes Laertius. The late transmission, possible inclusion of material from close associates, related letters and Vatican Sayings, and scholarly account of Epicurean ethics were checked against the Stanford Encyclopedia of Philosophy. Dates and authorship are stated at the level supported by that transmission rather than assigned false precision.