Picture this: You wake up one morning, and the world you know is gone. Cities are abandoned, the power grid has collapsed, and there are no phones, no internet, and no government. At first, you think you are alone, but then you realize the dead walk among the living. They are dangerous, but they are predictable — you know what they want.
The real danger is other survivors.
You have managed to find a small group. Together, you have a half-empty backpack of canned food, one jug of clean water, and a handful of basic weapons. That is all. No one is coming to save you. If you run out of food or water, you die. If another group finds you, they might trade with you…or they might kill you in your sleep.
Now imagine: You hear about a bigger settlement nearby. They claim to have walls, leadership, and even farming. But do you trust them? Will they welcome you, enslave you, or kill you and take your supplies? This is the world of the popular TV show, The Walking Dead. But it is also exactly the kind of world Thomas Hobbes asks us to imagine in Leviathan when he talks about the state of nature: a world without laws, without government, without security. A world where life is nothing but survival.
Few passages in political philosophy are as widely cited, debated, and dramatized as Thomas Hobbes’s account of the “natural condition of mankind” in Leviathan. In today’s reading, we will examine Chapter 13, where Hobbes lays out, in stark terms, what human life looks like in the absence of political authority.
Thomas Hobbes (1588–1679) was an English philosopher writing during one of the most chaotic times in his nation’s history: the English Civil War. The English Civil War (1642–1651) left an indelible mark on Hobbes’s thought. During this period, England was torn apart by conflict between supporters of King Charles I and the forces of Parliament. The struggle was not merely political but also religious, as disputes between Anglicans, Puritans, and Catholics fueled mutual suspicion and violence. Hobbes himself was a royalist, and his sympathies lay with the king, but his overriding concern was less about partisan victory and more about the destructive consequences of civil strife. He witnessed firsthand how disagreements about authority and religion could shatter social bonds, pit citizens against one another, and plunge a nation into war.
This context helps explain why Hobbes was so pessimistic about human nature and so insistent on the need for a strong sovereign power. For Hobbes, the civil war was living proof of what happens when central authority collapses: chaos, fear, and a return to what he called the “state of nature.” His great work Leviathan (1651), written in exile in Paris, was an attempt to provide both a diagnosis and a cure for this political disorder. Hobbes argued that peace and security could only be guaranteed if individuals collectively surrendered their right to self-rule and vested authority in a sovereign strong enough to maintain order. Far from being an abstract thought experiment, Hobbes’s political philosophy was forged in the crucible of England’s bloodiest and most destabilizing conflict.
In Chapter 13, “Of the Natural Condition of Mankind, as Concerning Their Felicity, and Misery,” Hobbes gives his most vivid account of life without government. This is the chapter in which we find his notorious claim that life in the state of nature is solitary, poor, nasty, brutish, and short. Let us turn to Chapter 13 and see why Hobbes believed in this dark existence, and how he envisions individuals escaping this way of life. You can find the full text here.
“Whatsoever therefore is consequent to a time of Warre, where every man is Enemy to every man; the same is consequent to the time, wherein men live without other security, than what their own strength, and their own invention shall furnish them withall. In such condition, there is no place for Industry; because the fruit thereof is uncertain; and consequently no Culture of the Earth; no Navigation, nor use of the commodities that may be imported by Sea; no commodious Building; no Instruments of moving, and removing such things as require much force; no Knowledge of the face of the Earth; no account of Time; no Arts; no Letters; no Society; and which is worst of all, continuall feare, and danger of violent death; And the life of man, solitary, poore, nasty, brutish, and short.”
This passage is the most vivid and influential statement of Hobbes’s central argument in Leviathan. Without a common political authority, human beings exist in a condition of radical insecurity that makes meaningful social life impossible. Hobbes’s point is not merely that life without government is violent, but that it is unproductive and uncivilized. By dramatizing what is lost without political authority, Hobbes prepares the ground for his justification of the social contract and sovereign power, arguing that submission to a common authority is a rational exchange for peace, stability, and the conditions necessary for human flourishing.
Equality of Ability – Humans are roughly equal in their capacity to harm one another, even if some are stronger or smarter.
Diffidence (Distrust) – Because we are equal, we compete for the same resources, which leads us to fear and suspect one another.
State of Nature – The condition where no common authority exists to enforce rules or laws.
War of All Against All – Hobbes’s description of the inevitable conflict in the state of nature.
Social Contract – The agreement to give up certain freedoms and submit to a sovereign power in order to achieve peace and security.
Hobbes begins Chapter 13 with a striking claim.
Section 1
Nature hath made men so equall, in the faculties of body, and mind; as that though there bee found one man sometimes manifestly stronger in body, or of quicker mind then another; yet when all is reckoned together, the difference between man, and man, is not so considerable, as that one man can thereupon claim to himselfe any benefit, to which another may not pretend, as well as he. For as to the strength of body, the weakest has strength enough to kill the strongest, either by secret machination, or by confederacy with others, that are in the same danger with himselfe. And as to the faculties of the mind […] I find yet a greater equality amongst men, than that of strength. For Prudence, is but Experience; which equall time, equally bestowes on all men, in those things they equally apply themselves unto. That which may perhaps make such equality incredible, is but a vain conceipt of ones owne wisdome, which almost all men think they have in a greater degree, than the Vulgar; that is, than all men but themselves, and a few others, whom by Fame, or for concurring with themselves, they approve. For such is the nature of men, that howsoever they may acknowledge many others to be more witty, or more eloquent, or more learned; Yet they will hardly believe there be many so wise as themselves: For they see their own wit at hand, and other mens at a distance. But this proveth rather that men are in that point equall, than unequall. For there is not ordinarily a greater signe of the equall distribution of any thing, than that every man is contented with his share.
At first glance, this passage seems counterintuitive. Are people truly equal? Some are taller than others; some stronger, quicker, even more intelligent. Yet, Hobbes insists that these differences are not as important as they seem when we consider all the ways individuals interact.
Hobbes’ reasoning is straightforward. Even if one person is physically stronger, the weaker can compensate with tools, weapons, or strategy. A knife or well-placed trap can kill even the strongest person. Conversely, the intelligent can be bested by the less clever through sheer cunning, alliances, and patience. Every group has the ability to be attacked by an opposing group, and no one has an upper hand when it comes to survival. This is what Hobbes called the equality of ability. Therefore, according to Hobbes, no one is invulnerable, and every human being is a potential threat to every other.
It is important to note that Hobbes’s use of equality here is not equality in the modern sense of rights. Hobbes is not saying people deserve equal treatment. He is saying that their existence in the state of nature is equal in terms of vulnerability – each person is capable of killing another.
This universal equality breeds diffidence or (distrust) – a constant state of insecurity and mistrust. Since each person knows that others are capable of harming them, no one can feel entirely safe. This fear is not irrational; it is a logical conclusion of the human condition in the absence of authority.
Let’s imagine two individuals in the state of nature who need land for growing food, a scarce resource absent an organized society. Both want fertile land near a water source, and both know that if the other claims it, they may be left with nothing. Further, both know that the other is capable of violence, forming temporary alliances with others nearby or attacking them without warning. They will inevitably become rivals, leading to conflict. Even if neither wants conflict, the mere possibility of attack makes each feel compelled to act preemptively.
Hobbes emphasizes that when two or more people desire the same scarce resource, which cannot be shared, they will inevitably become rivals. Scarce resources are not limited to material things like food or land; scarcity extends to things like safety, status, and honor. So, in a world where resources are limited and no authority exists to enforce agreements between individuals, equality of vulnerability ensures competition.
P1: Humans are roughly equal in ability.
P2: If two humans are equal in ability, then they have equal hope of achieving the same goals.
P3: If two humans have equal hope of achieving the same goals, then they will desire the same scarce goods.
P4: If two people desire the same scarce goods, they become enemies.
C: Therefore, human equality leads to distrust, rivalry, and conflict.
Having laid out the theory of natural equality, Hobbes turns to the reasons why human beings inevitably come into conflict.
Section 2
So that in the nature of man, we find three principall causes of quarrel. First, Competition; Secondly, Diffidence; Thirdly, Glory.
The first, maketh men invade for Gain; the second, for Safety; and the third, for Reputation. The first use Violence, to make themselves Masters of other mens persons, wives, children, and cattell; the second, to defend them; the third, for trifles, as a word, a smile, a different opinion, and any other signe of undervalue, either direct in their Persons, or by reflexion in their Kindred, their Friends, their Nation, their Profession, or their Name.
Hobbes argues that conflict between individuals in the state of nature isn’t random or accidental. It arises from fundamental features of human life without a common authority. Because people are roughly equal in their ability to harm one another and have overlapping desires for scarce goods, three deep-seated motives push them toward conflict: competition for resources, diffidence leading to preemptive self-defense, and the pursuit of glory or reputation. These forces make conflict not just possible but likely, showing that without an enforcing power, human interactions tend toward rivalry rather than cooperation.
Hobbes identifies three fundamental causes of conflict: competition, diffidence, and glory. According to Hobbes, each of these causes represents a distinct motivation for violence and hostility in the state of nature. The most straightforward cause is competition for resources. People need food, shelter, and other goods to survive. Resources are finite, and if two or more people want the same scarce item, at least one person will be left disappointed. In the absence of law and institutions, the only way to secure goods in the state of nature is through force. Therefore, competition leads people to invade others for gain. Hobbes puts it simply, “The first maketh men invade for Gain.” Imagine, for example, two families in the state of nature seeking the same fertile plot of land. Absent any property law or government to enforce ownership, the only way for one family to secure the land would be to drive the other family out or kill them.
This approach to securing property breeds the second cause – diffidence, which means distrust or fear. Since everyone is vulnerable, as argued by Hobbes’s equality doctrine, each individual knows that others may attack them. The insecurity of not knowing whether or not others will attack you leads to the logic that it would be better to attack first than sit back and wait for others to attack you. If I fear you might attack me tomorrow, then I may feel compelled to attack you today in order to protect myself. In other words, the insecurity leads to the determination that a preemptive strike is in your best interest. Thus, diffidence leads people to invade others for safety.
In addition to survival, Hobbes argues that humans also desire respect and recognition. The third cause of violence, then, is glory, or the pursuit of reputation and honor. Violence and preemptive attacks can also be motivated by perceived slights or disrespect between individual(s). Disrespect or a slight against others can trigger violence even if material goods – like food or land – and safety are not at risk. Individuals will attack each other in order to maintain their perceived status – e.g., to maintain their status as strong or intelligent. Glory leads people to invade for reputation as well. Invading neighboring people(s) can show strength toward other potential invaders and avenge slights committed by neighbors.
Taken together, these causes do not occur in isolation. A single conflict may involve one, two, or all three of these causes at once. Competition for scarce resources, diffidence about others’ intentions, and glory in maintaining honor or deterring disrespect are perfect ingredients for violence. In Hobbes’s state of nature, these combinations ensure that conflict is not the exception but the rule. Violence can emerge from the drive for wealth, the need for security, or the hunger for status. In Hobbes’s logic, these three causes show why equality and vulnerability lead not to peace but to constant tension. Together, they explain why the state of nature is a state of war.
Having established the causes of conflict, Hobbes draws the following conclusion: in the absence of a common authority, human life is characterized not by peace, but by a perpetual state of war – or, a war of all against all.
Section 3
Hereby it is manifest, that during the time men live without a common Power to keep them all in awe, they are in that condition which is called Warre; and such a warre, as is of every man, against every man. For WARRE, consisteth not in Battell onely, or the act of fighting; but in a tract of time, wherein the Will to contend by Battell is sufficiently known: and therefore the notion of Time, is to be considered in the nature of Warre; as it is in the nature of Weather. For as the nature of Foule weather, lyeth not in a showre or two of rain; but in an inclination thereto of many dayes together: So the nature of War, consisteth not in actuall fighting; but in the known disposition thereto, during all the time there is no assurance to the contrary. All other time is PEACE.
Hobbes does not mean war only in the narrow sense of active fighting like active military conflicts with direct killings. He defines war more broadly: war is not only battle, but the known disposition to battle. In other words, even when no one is actively fighting, if people live in constant fear and readiness for conflict, they are already living in a state of war. Defining war broadly is crucial for Hobbes’s argument. Peace is not merely the absence of violence, but the presence of security. Where no one feels secure, there is no peace.
Given that Hobbes has shown the state of nature is a perpetual state of war, he moves to describe his famous account of life under the conditions of no laws, government, or enforcement. A state of nature has no industry, because no one can be sure of benefiting from their production. Why would anyone develop anything if it might be taken from them by an invader? There are no arts or culture since creative endeavors require stability and security over time. Trade is non-existent since commercial activity requires trust and predictability in your trading partners. Just as art and culture require stability, so too does science and discovery.
Most of all, society is not possible since society relies on security, stability, long-term planning, and trust. Ultimately, the state of nature is a state of living in continual fear and danger of violent death. Or, as Hobbes famously puts it,
Section 3 (continued)
Whatsoever therefore is consequent to a time of Warre, where every man is Enemy to every man; the same is consequent to the time, wherein men live without other security, than what their own strength, and their own invention shall furnish them withall. In such condition, there is no place for Industry; because the fruit thereof is uncertain; and consequently no Culture of the Earth; no Navigation, nor use of the commodities that may be imported by Sea; no commodious Building; no Instruments of moving, and removing such things as require much force; no Knowledge of the face of the Earth; no account of Time; no Arts; no Letters; no Society; and which is worst of all, continuall feare, and danger of violent death; And the life of man, solitary, poore, nasty, brutish, and short.
Without security, life collapses into a constant fight for survival. Fear is the important feature here for Hobbes – in fact, it is the dominant feature of the state of nature. Hobbes argues that if there were constant fighting, life would be bad but not intolerable. What makes life intolerable is the constant threat and anticipation of war. Not knowing whether you will be attacked today, tomorrow, or a week from now leads to a life of constant fear and unpredictability. Fear, then, drives individuals to violence.
In summation, Hobbes argues that the state of nature is a state of war. This is a condition of no authority to enforce peace and security. War is defined not just as active fighting, but by the disposition to fight. In this condition, there is no industry, culture, trade, etc. – only fear. As a result, life becomes “solitary, poor, nasty, brutish, and short.”
Imagine a world like the one described at the beginning of this entry: a zombie apocalypse where government has collapsed, cities are abandoned, and survival depends on scarce resources. The undead are dangerous, but predictable. You know what they want, how they move, and how to avoid them if you are careful. Other humans are different.
You and a small group of survivors have secured a temporary shelter. You have enough food and water to last a few days, but not much more. Every night, someone must stay awake to keep watch. Every sound outside – a footstep, a cough, maybe even a knock – could signal danger.
One day, you encounter another group of survivors. They claim to be peaceful and suggest working together. Cooperation could mean shared labor, greater security, and a better chance of long-term survival. But it could also mean betrayal. They might attack you in your sleep, take your supplies, or abandon you when resources run low.
You face a dilemma. If you trust them and they betray you, the cost could be death. If you refuse to trust them (maybe even attack them first) you may preserve your safety, but at the cost of peace and cooperation. Even if you choose not to attack, you must live with constant suspicion and questioning: Will they strike first? Will it ever be rational to trust other groups? At what point, if ever, will cooperation become more rational than suspicion?
Hobbes does not leave his readers with the bleak picture of the state of nature. He concludes with the following question: How do individuals escape the state of nature? Hobbes’s view of human nature is not that people are naturally virtuous, cooperative, or good. Rather, humans are the exact opposite: self-interested, competitive, and fearful. It is because life is intolerable in the state of nature that people are led to reason a way out.
Section 6
And thus much for the ill condition, which man by meer Nature is actually placed in; though with a possibility to come out of it, consisting partly in the Passions, partly in his Reason. The Passions that encline men to Peace, are Feare of Death; Desire of such things as are necessary to commodious living; and a Hope by their Industry to obtain them. And Reason suggesteth convenient Articles of Peace, upon which men may be drawn to agreement. These Articles, are they, which otherwise are called the Lawes of Nature […]
Despite his grim picture, Hobbes thinks humans can escape the state of nature. Our fear of death and desire for comfort push us toward peace. Reason suggests laws of nature, principles of cooperation that point the way to forming a social contract.
Hobbes identifies three motives that push individuals toward wanting to form a lasting peace. First is the fear of death. The ever-present threat of violent death in the state of nature leads to life being intolerable. Fear, then, is the most powerful motive to push individuals toward wanting a peaceful union. Fear of death and wanting a pathway out speaks to Hobbes’s view that self-preservation is the most fundamental human drive. Further, people do not merely want to survive; they want to thrive and be comfortable – they want a commodious life. As we discussed in section three, farming, trade, and the comforts of society are only possible in a secure society, and as a result, individuals are driven toward bringing about the conditions of security and peace for commodious gain. However, as also discussed in section three, individuals are not willing to produce goods unless they are certain they won’t have their things stolen or destroyed. People wish to be industrious, but can only do so where laws exist and are enforced. Thus, according to Hobbes, these motivations push human beings to seek a more stable condition.
Here is where Hobbes introduces reason as the faculty that guides us toward peace. While passions – such as fear – drive us to fight, they also create the desire for safety – such as comfort and security. Reasons formulate the terms on which peace is possible. For example, it is rational to give up preemptive strikes if others also agree to give up this action. Further, it is rational to form contracts if there is a guarantee that the contract will be upheld and enforced. Reason, then, leads individuals to believe that peace is possible through contracts but only if there is a way to enforce the agreement.
Therein lies Hobbes’s central political argument: agreements are meaningless without enforcement. In the state of nature, even if two people agree not to harm each other, each must still fear betrayal. The only way to make agreements reliable is for all individuals to submit their natural liberty – their natural freedom to act as they wish – to a common authority that can compel obedience. This common power becomes the sovereign, and is created through the social contract entered into by all individuals. Without this sovereign figure, power, fear, and distrust will pull individuals back into a state of war. Therefore, Hobbes argues, the road to peace requires the creation of a Leviathan – a centralized political authority with enough strength to enforce contracts, compel obedience, and guarantee security.
In Chapter 13 of Leviathan, Hobbes argues that humans, though equal, inevitably fall into distrust and conflict in the absence of government. This state of nature is a state of war, defined not only by fighting but by the constant threat of violence. Life in such conditions is unstable, fearful, and ultimately “solitary, poor, nasty, brutish, and short.” Yet Hobbes also points to a way out: human passions for peace and reasoned agreements lead to the creation of social contracts and sovereign powers. For Hobbes, only through strong authority can people escape the chaos of the state of nature and live securely together.
If you want to learn more about Hobbes’s philosophy, especially his political philosophy, you can read the whole text of the Leviathan in addition to his other famous political work De Cive (On the Citizen). For entry-level secondary sources, there is a good entry on Hobbes’s moral and political philosophy at the Internet Encyclopedia of Philosophy, and this short introduction by Richard Tuck offers a clear and accessible account of Hobbes as a political theorist.
This work has been adapted from Leviathan, a title from the Project Gutenberg Ebook library, by Thomas Hobbes. This work is in the public domain. All images were created using Midjourney.
Horn, Corey. 2026. “Life in the State of Nature: Thomas Hobbes’s Leviathan, Chapter 13.” The Philosophy Teaching Library. Edited by Robert Weston Siscoe, <https://philolibrary.crc.nd.edu/article/the-state-of-nature>.
Underlier (Greek hypokeimenon) – in Aristotle’s account of change, what remains constant throughout the change and by which form is acquired and privation is lost. For instance, if Socrates becomes musical from being unmusical, Socrates is the underlier. (N.B. This same Greek term is also, especially in logical and metaphysical contexts, often translated as “subject”.)
Relations of Ideas – these are claims we come to believe without any sensory experience required. For instance, we can come to realize that a circle has a perfect center point without discovering any perfect circles in the world. All we need to do is think clearly about what it means to be a circle!
Here, Kant refers to Frederick the Great (Friedrich II, 1712-1786), who was King of Prussia. A supporter of the Enlightenment, Frederick endorsed social and political change by abolishing torture and expanding the educational sector. He suspended censorship for newspapers with the exception of political content. Supporting freedom of religion in general, he nevertheless favored protestants for political higher office and did not grant Jews civil rights.
Monarchy – A monarchy is a state where political deliberation is performed by one person (generally a king or queen).
Phalaris (c. 570-549 BCE) was, by most accounts, the very opposite of Cyrus, and he was used as an example of tyrannical cruelty in antiquity. He was tyrant of Acragas (now Agrigento) in Sicily. Diodorus Siculus records an infamous account of Phalaris’s torturing his enemies in a bronze bull placed over a roaring fire.
Cyrus the Great (d. 530 BCE) was the first emperor of the Persian Empire and a commonly used exemplar of the “enlightened monarch” in antiquity. He was renowned for his tolerance and care for his subjects. Xenophon, a student of Socrates, wrote a partly fictionalized biography of Cyrus called The Education of Cyrus (Cyropaedia). Peter Drucker, an influential 20th-century management theorist, called the Cyropaedia the best book on leadership.
Republic (res publica) – Cicero’s short definition of res publica is res populi (the ‘people’s thing’). Later in the Republic, Cicero famously defines a republic (1.39) as an assemblage of people associated with each other by consensus on justice (ius) and mutual benefit (utilitas).
Scipio Aemilianus Africanus was a hero among many Romans, but his reputation today is far less straightforward. Scipio Aemilianus led a Roman military campaign resulting in the utter destruction of the city of Carthage in 146 BCE. The Carthaginians were a prosperous Phoenician people in North Africa and rivals to Roman power. It has been argued that this act of ‘national extermination’ meets the modern definition of genocide. How should this knowledge impact how we view Scipio’s political philosophy expressed here?
This famous phrase, known by the abbreviation SPQR (senatus populusque Romanus), served as something like the official title of the Roman state (compare ‘USA’, ‘USSR’, ‘UK’), and encapsulated the ideal of a res publica (common property in public hands shared between the people and a council of elders).
Contemplation: The activity of human beings’ rationality. Contemplation is more than just thinking; it’s thinking excellently about ultimate truths. Contemplation is the ultimate activity associated with human flourishing.
Eudaimonia: Often translated as ‘happiness’ (in this text) or ‘flourishing’, eudaimonia is the activity of living the best possible life for a human being. Eudaimonia is more than just feeling happy or contented – it’s the idea that there is a best way to live for human beings.
Virtue: Virtues are cultivated tendencies to perform our function excellently, which allow us to reliably do the right thing, to the right extent, for the right reasons, given the demands of a specific circumstance. There are three components of virtues: virtues involve (a) skillful activity – they’re excellences after all!, (b) proper motivation, and (c) appropriate judgment – they often lead to judgments about what is the right thing to do, which requires careful attention to the circumstances.
Pleasure: The enjoyable feeling that accompanies some activities. Some philosophers (but not Aristotle!) think that pleasure is the only thing that is good in itself
Endoxic Method: An argumentative structure that begins by laying out the endoxa, or the beliefs of the many or the wise, then raises apparent problems for those views and develops a resolution to those problems.
The Problem of Induction: A problem for reasoning about the future based on past experiences. How can we be justified in believing that patterns of events in the past will continue into the future?
A Priori: Hume is using the term ‘a priori’ to denote the kind of reasoning that allows one to gain knowledge as relations of ideas—in other words, reasoning from one necessary, definitional truth to another.
Justification: the concept of justifying one’s thinking, or one’s beliefs, is important in epistemology. Roughly, one’s thinking or belief is justified when there is good reason for it, or when it is well supported or well evidenced. All of these are ways of referring to some connection between what we think or believe and what is, or to some way of at least making ourselves think that we are closer to the truth.
Inference: The psychological process of moving from one thought to another, such as moving from the thought “it’s raining, and I don’t want to get wet” to “I should get my umbrella”, or from “I am tired, and it’s getting late” to “I should get some sleep”. Nowadays, philosophers tend to use the term ‘inference’ to mean the same as ‘reasoning’, and tend instead to use the term ‘association’ to refer to movements between thoughts that are not based on any logic or evidence.
Matters of Fact: Knowledge that is gained by experience, such as by observing or experimenting with objects in the world. For example, knowing whether all swans in the world are white requires somebody to examine the many swans in the world and make sure they do not happen to discover a black one (and in fact, there are black swans!).
Relations of Ideas: Knowledge that is gained just by sufficiently clear thinking, without having to observe or experiment with objects in the world. For example, knowing that a triangle has three sides is something you can know just because of what it means to be a triangle, hence without having to carefully examine triangular objects that you find throughout the world.
Reasoning: Developing arguments to try and support the truth of one’s beliefs.
Causation: A relation between events, where one event (cause) is responsible for another (effect). Eating too much chocolate can cause the effect of having an upset stomach, and not getting enough sleep can cause someone to be grumpy.
Epistemological Theories: Theories about the nature and possibility of knowledge – whether, when, how, and to what extent we can know about reality, such as the physical world, or our own consciousness. For example, one epistemological theory says that we can gain understanding of our own consciousness by studying the brain, whereas other theories say that we can only gain knowledge of consciousness by reflecting on our own inner experiences.
Aristotle means “happy” in the sense of a person who has developed a complete character, lived a full life, and become a true example of human goodness.
Happy Person – Someone who has developed her entire self well and lived a complete and flourishing life. She is a real and positive example of how we should live.
This is where Aristotle defines virtuous friends. These are friends who you actually answer the phone for. These are the friends who you ask for advice on work, love, and life. They are the friends that celebrate you for being you, but they also tell you when you’re messing things up. Not only do they love you, but you love them and try to be the same kind of friend to them too.
This is where Aristotle defines pleasurable friends. These are your TikTok, Snap Chat, or Instagram friends, the ones you post to social media when you’re having a good time.
This is Aristotle’s explicit definition of useful friends. These are your LinkedIn friends, those who you like networking with at events or enjoy working with on projects.
Virtuous Friendship – A friendship where people set as their goal for their friendship becoming good people together and living happy lives just because they value the good of their friends as persons. These are also known as “perfect” or “true” friendships. They are usually between people who are equally good. And they might be limited to people of equal social status, wealth, and power. Aristotle doesn’t think that any happy person will lack virtuous friends. But he thinks it’s likely that we’ll only have a few of this sort.
Pleasurable Friendship – A friendship where people set as their goal for their friendship some pleasant goal, such as friendship between people who go out on the town together. These friendships are plentiful and easy to form and dissolve.
Useful Friendship – A friendship where two people set as their goal for their friendship some useful or utilitarian purpose, such as friendship between work colleagues. These friendships are plentiful and easy to form and dissolve.
Aristotle uses “friend” broadly for any relationship between people who like each other, wish good things for each other, and get something out of spending time together.
Friendship – A relationship between two people who like each other, generally wish each other well, and have a goal for their interactions.
Happiness – The final end and highest good of human life. The perfect good that objectively fulfills human nature and subjectively satisfies desire.
Happiness Criteria – The conditions that the true object of happiness must satisfy. They are: finality, intrinsic value, purity, internality, authenticity, stability, self-sufficiency, completeness.
Object of Happiness – The thing in which happiness essentially consists, the attainment of which will make us truly happy.
Highest Good – The greatest good for a human being.
Final End – The ultimate goal of human life. All of our other goals are chosen for the sake of this final end.
Constituent Principles – Parts of a material object that cause the object to be the sort of thing that it is, but that cannot be removed from that object (in the way that some properties can be gained or lost). For Aquinas, this would include things such as form (the structure of a material object) and matter (that which is structured). For example, Dylan’s form is his soul, and his matter is his body. His soul and body are distinct, but Dylan could not exist if he were not composed of both.
Accident/accidental property – A property that something can possess or not possess while still remaining the thing that it is. For example, Dylan could grow taller, or he could stop being musical, without becoming a different person. By contrast, rationality is an essential property of Dylan, since being rational is part of the “what it is to be” of a human being.
Subject/Suppositum – Something or someone that can bear properties but is not itself a property that something else can bear. Dylan can have properties, like being short or being musical, but no one can have Dylan as a property.
Property – A feature that an object has. For example, a ball could be orange, which means that the ball has the property of orangeness. In many cases a property can be gained or lost. The ball could be painted green, in which case it would gain the property of greenness and lose the property of orangeness.
Actuality – The being, or act of being, of a thing. For example, hot water is actually hot (the water is hot), even though it is potentially cold. Likewise, a boy is actually a human being (he is a human being), even though he is also potentially a full-grown man (and he will still be an actual human being when he becomes a full-grown man).
Potentiality – Ways a given thing can become different from the way it is now. For example, cold water is potentially hot, since it can be heated up, and an acorn is potentially an Oak tree since it can grow to full size under the right conditions.
Essence – The “what it is to be” of a thing. For example, the essence of a human being is to be a rational animal, and the essence of a cheetah is to be the fastest land animal.
Principle of Specialization – The idea that work is more efficient and more effective if each worker specializes in exactly one task.
Extrinsic Value – Value a thing has that is dependent on something else. Extrinsically valuable things are worth pursuing because they get you something else that is valuable. Money, for instance, is only useful because it can be exchanged for other things.
Intrinsic Value – Value a thing has independently or inherently. Intrinsically valuable things are worth pursuing for their own sake.
Adeimantus and Glaucon were Plato’s older brothers (along with an older sister, Potone). They were both honored for military valor at a battle with Megara. We know little about their lives otherwise. Potone had a son, Speusippus, who inherited leadership of the Academy upon Plato’s death.
Thrasymachus was a real person, who lived about 459-400 BCE moved to Athens from Chalcedon to become a sophist (a professional teacher and public speaker). Only a few fragments of his work survives
Prudence – Prudence is virtue wherein a person is able to choose, in any given situation, the course of action that will lead to greater happiness. For example, a prudential person knows when it is appropriate to continue a difficult conversation and when it is best to wait for a more appropriate time.
Pleasure – Epicurus would have us think about pleasure as coming in two forms: moving and static. Moving pleasures are the type that we experience in the process of satisfying a desire (this coffee tastes amazing!). Static pleasure is the feeling of being satisfied — no longer experiencing need or want (I am feeling so peaceful sitting in the park). Epicurus thinks these static pleasures are the best sort.
Epicurus believed that reality is composed of matter. This sets him apart from other philosophers of the time who, often influenced by Plato, believed that reality is composed of both the material and immaterial (like the soul, or the Platonic forms).
Happiness – Epicurus uses the Greek word “eudaimonia,” which is typically translated into English as “happiness.” Whereas today happiness is most often used to describe a momentary feeling (this new notebook makes me happy!) Epicurus means something more like a consistent state of well-being and contentment.
Unconditioned: an ultimate explanation of reality. For example, if I explain why it is raining today by appealing to some atmospheric conditions, I can always ask for the cause of those conditions, and so on. Only a cause that is not caused by anything else (something unconditioned) would give us an ultimate explanation.
Transcendental Idealism: Kant’s mature philosophical position. It holds that appearances are not things in themselves, but representations of our mind. It is opposed to transcendental realism, which identifies appearances with things in themselves.
Appearances (vs. things in themselves): things as they are experienced by us (also known as phenomena). They should be distinguished from things as they are independently of our experience (things in themselves or noumena).
Metaphysics: the study of what there is. Traditionally, metaphysics is divided into general metaphysics and special metaphysics. The former investigates the general features of reality and asks questions such as ‘What is possible?’. The latter studies particular kinds of being and asks questions such as ‘Does God exist?’ or ‘Is the soul immortal?’.
Reason: the faculty that knows a priori. Kant uses this term in a general sense (the knowing faculty as such) and in a specific sense (the faculty that demands ultimate explanations).
A priori: term denoting propositions that can be known independently from experience. For example, propositions such as ‘All bachelors are unmarried’ or ‘The whole is greater than its parts’ can be known without recourse to any experience.
Make sure not to think that ‘unjustified’ means ‘false.’ Even if they are true, the point is just that this would not be something that had been shown.
‘Absolute’ might be a confusing word, here. Socrates means that the geometers are not reasoning about their drawing of the square, for example, but of the square itself. They do not conclude that, for the square they drew, the area is equal to the square of a side – they conclude that this is true for squares as an intelligible object, or, as Plato would say, the Form of the square.
By ‘science’, Plato means to be talking about all rational disciplines, including mathematics.
The form of the beautiful has to be perfectly beautiful because all instances of beautiful things are explained by it, so it has to be responsible for the highest possible degrees of beauty possessed by anything. Moreover, it has no trace of ugliness in it.
The form of the beautiful has to be immaterial because all the many beautiful things do not share any material – that is, they are all made of different stuff.
Form (εἶδος / ἰδέα) – Intelligible, immaterial, perfect entities that explain the unity among the many things which share the feature named by the entity (e.g., Beauty, Squareness, Oddness). For example, think of a square. There might be many different squares, but they all share features like having four sides of equal length. So, the Form of Squareness would include all of those features that make something a square.
Guardian – This is the name Plato gives to the ruling class in his ideal city. Think of them as philosopher kings – they have complete control over the organization of the state. The Republic is partially about why Plato thinks they would be needed for an ideal system of government and what they would need to learn to do the job well.
Plato has previously argued that we are made up of different parts. The first part is the appetitive which is responsible for our desires for food, sex, and other bodily needs. Then there is the spirited part, which longs for fame and honor. Finally, he identifies the rational part, which discerns what is good and bad for us through reason. The parts can all come into conflict with one another, and managing their relations is what Plato thinks justice is all about.
Soul (ψῡχή) – What Greeks meant by this word is controversial. For now, think of it as the thing that makes you different from a rock or other objects, the thinking and experiencing part of you as well as the part of you that acts and makes decision. You might use the word ‘mind’ or ‘self’ to talk about this.
Virtue – Virtues are the character traits that make a person good. For example, most people consider courage and generosity to be virtues. English-speakers usually reserve the word ‘virtue’ for human beings, but in ancient Greek the word can be more comfortably applied to other beings as well.
Was it his burly physique, his wide breadth of wisdom, or his remarkable forehead which earned him this nickname?
Aporia – A Greek term for “being at a loss” or “clueless.” Socrates often questions people until they have no idea how to define something that they thought they understood.
You might be confused by the word ‘attention’ below. In Greek the word is therapeia, from which we get the English word ‘therapy.’ It primarily means the same as ‘service’ as in ‘to serve,’ but shades into ‘worship,’ ‘take care of,’ and ‘attend to.’
Meletus – A poet and citizen of Athens and one of Socrates’ accusers. Amongst other things, Meletus accused Socrates of impiety and corrupting the youth.
Divine Voluntarism – The idea that God is free to determine even the most basic truths. If divine voluntarism is true, then God could have made it so that 2+2=5 or so that cruelty and blasphemy are holy and good.
Euthyphro Dilemma – The question, “Is a thing holy because the gods love it, or do the gods love it because it is holy?” The general idea of a forced choice (or “dilemma”) about the true order of explanation occurs often in philosophy and gets referred to by this term.
Essence – What a thing fundamentally is. A square might be red or blue without changing the fact that it’s a square, but a square must have four sides, so having four sides is part of a square’s essence.
Definition – The perfect description of a thing. A definition should pick out all and only examples of a thing. For example, ‘bachelor’ might be defined as ‘unmarried man,’ because all unmarried men are bachelors, and only unmarried men are bachelors.
In Disney’s retelling of the Hunchback of Notre Dame, the clergyman Claude Frollo orders the death of many Roma on religious grounds. It is clear, however, that he is really motivated by spite and his unrequited lust for the Romani woman Esmerelda.
Spanish conquistadors were shocked by the scope of ritual human sacrifice among the Aztecs, as hundreds or even thousands of people were sacrificed each year. The Aztecs thought that the sacrifices could repay the sacrifices the gods had made in creating the sun and earth.
Zeus – The god of sky and thunder in ancient Greek mythology, Zeus was depicted as chief among the gods and called the father of the gods and men.
Forms – The perfect, divine, and intelligible entities that exist independently of the physical world. They are comprehensible only through reason, not through our senses, and their existence explains the properties of objects in the physical world.
Recollection – The soul existed prior to birth; during this time it learned everything, and hence all learning is only recalling what we already know.
Immortality of the Soul – Unlike the body, the soul is not subject to physical death, because it is immortal and indestructible.
Philosophy – The practice of preparing the soul for death by training it to think and exist independently of the body
Death – Plato understands this as the soul’s separation from the body
Human Identity Across Time – Locke’s notion that any human stays the same across time if, and only if, it maintains the same (distinctively human) organizing structure of parts.
Substance Identity Across Time – Something is the same substance across a segment of time if, and only if, it continuously exists across the relevant segment of time without gaining or losing any of its parts.
Immaterial Soul – A personal thinking substance without any physical constitution.
Personal Identity Across Time – Whatever makes someone the numerically same person (i.e., that very person) at different times; according to Locke, it is a relation of first-person consciousness via memory.
Person – Locke’s forensic definition of person (pertaining to courts of law regarding the justice of praise, blame, reward, or punishment): a thinking, intelligent being, that has reason and reflection, and can consider itself as itself, the same thinking thing in different times and places.
The Prophet Muhammad is a central figure in Islam. He is viewed as the last of a long line of prophets, which includes Moses and Jesus. He is responsible for writing the Quran, which was dedicated to him by the angel Gabriel. His life and sayings are recounted in the Hadith; he is viewed as an exemplary role model of Islamic life and faith.
Exhortation — The method of understanding and interpreting Truth available to the common people. The majority of people take scripture literally and understand truth and right action based upon this understanding. They are persuaded by the vivid imagery of the Quran and the rhetorical exhortations of religious leaders. Averroes takes this to be lowest form of understanding
Dogmatic Discourse — The method of understanding displayed by those who, through natural ability and habit, are able to have a deeper understanding of the Quran, and of the truths it illuminates. These people know that not all of the scriptures are to be taken literally, and that greater underlying Truths are revealed by interpreting some elements allegorically. Still, they err on the side of dogmatism and literal interpretation whenever uncertainty arises. Averroes associates this way of thinking with Muslim theologians and views this to be the middle level of understanding.
Philosophical Inference – The type of understanding associated with philosophical demonstration or argument. This is the highest level of understanding, accomplished by a select few, who have a natural capacity for philosophy and proper philosophical training.
Law — The Quran (the central religious text of Islam) and, to a lesser extent, the Hadith (reports of what the prophet Muhammad said and did). Averroes is concerned with explaining how philosophy relates to what Muslims take to be the unerring Truth regarding God and the nature of existence, as they are expressed in Scripture.
Occasionalism — a theory claiming that God is the only true cause of changes in the world. For example, when you high-five me, you’re not really the cause of the stinging sensation I experience. God is the cause. Your high five is just the occasion on which God causes it.
Interactionism — a theory claiming that things in the world can truly cause changes in each other. For example, when you high-five me, you truly cause me to experience a stinging sensation in my hand.
Substance Dualism — a theory claiming that the mind (or soul) and body are two distinct and very different things.
Body — what it sounds like! The body is the physical part or aspect of a thing and has characteristics like shape, size, etc.
Soul — that part or aspect of a thing involving mental aspects of their existence, e.g., thoughts, feelings, decisions, etc. The “soul”, in this sense, is more or less just the mind.
Causal Interaction — When one thing acts (i.e., itself does something) and in so acting makes another thing change. For example, when you high-five me, you cause me to experience a stinging sensation in my hand.
God as God – The phrase “God as God” is basically a synonym for “God the subject.” In other words, it refers to God precisely in God’s status as an incomprehensible divine Other.
Incarnation – The Christian doctrine of the incarnation is the notion that the word of God became fully human in the person of Jesus of Nazareth. It is closely associated with the doctrine of the trinity, which asserts that God the Father, God the Son (Jesus as the word made flesh), and God the Holy Spirit are one God.
Religious Fanaticism – In Feuerbach’s use of the term, a religious fanatic is someone who is unwaveringly faithful to God as an utterly mysterious superhuman being. They subordinate other things—especially the love of other humans—to submission before this divine other.
God the Subject – When Feuerbach refers to God as a subject, he is referring to the commonplace religious belief that God is a being who has various attributes, like a loving nature.
Faith Separates Man From God – Faith separates God from man in this sense: it treats God as a mysterious other, a being radically distinct from us.
Faith – Belief in and fidelity to a transcendent divine subject like God.
Orthodoxy – Orthodoxy refers to “right belief,” and it is concern with identifying heresies and ensuring that people believe and practice correctly.
Indirect Form of Self-Knowledge – Feuerbach’s view is that religious belief is a naive way of relating to our human nature and its perfections. It is naive or childlike because it treats these as external realities that belong to God. He believes a mature and contemplative person realizes these don’t belong to God, but rather to our species, abstractly conceived.
Above the Individual Man – The human perfections are “above the individual” insofar as no particular individual ever perfectly realizes them. They are abstractions.
Divine Trinity – Feuerbach is having fun here. He is using the theological phrasing of the Trinity to talk about human perfections. In calling reason, love, and freedom of the will “divine,” he means they are absolutely good; they are activities whose goodness is intrinsic to their practice or exercise. This isn’t a novel philosophical view. For example, Immanuel Kant argued that autonomy or a good will is the only thing which is unconditionally good.
Perfections – The end to which a faculty or power is ordered. For example, omniscience would be the perfection of the intellect. Traditionally, God is said to possess all perfections.
Love – When Feuerbach writes about love, he is referring to unconditional concern for others and the desire for fellowship with them. He is here asserting that love, understood in this sense, is the perfect activity of the affective faculty. In other words, our feelings and passions are fully actualized and engaged in an intrinsically valuable activity when we genuinely love others.
Infinite – The infinite is whatever can be understood as unbounded or unlimited. Human nature in the abstract is unbounded and unlimited. It is only bounded or limited in its concrete form as it is realized by particular material individuals.
Higher Consciousness – The sort of consciousness that mature human beings possess, but which other animals do not. It is “higher” than animal consciousness because it involves thinking abstractly about the form or essence of things.
Science – Feuerbach uses the term science in its classical sense, meaning systematically organized knowledge. Any body of knowledge founded on an understanding of first principles and the essences of things is a science in this sense.
Popular Sovereignty – The view that a government’s authority to rule comes from the people, making a ruler subject to the will of their citizens.
The Divine Right of Kings – The theory that kings are chosen by God and thus that political revolt is a rebellion against the will of God.
Synthesis – The prefix ‘syn-’ means “together,” so a synthesis “brings together” or combines elements of both a thesis and its antithesis.
Antithesis– An antithesis is the contradiction of a thesis. For example, internationalism could be understood as the antithesis of nationalism.
Thesis – In Hegelian terms, a thesis can be understood as a position or theory. Examples include any of the “-isms” that we discuss in science, history, and philosophy, such as Darwinism, capitalism, nationalism, etc.
Progressor’s Temptation – a unique temptation for those making progress in which pride impedes their further progress and leads to backsliding.
Progressors – those who are not yet expert Stoic practitioners, but who are also aware of the fact that they must change their lives in that direction. They are working on making progress.
Intellectualism – the philosophical view that our motivations and emotions are all judgments. The reason why you do something, your motivation, is because you believe it’s the right thing to do. The reason why you feel good or bad about something, an emotion, is because you believe that something good or bad happened to you.
Duties – acts of service, obedience, and respect that we owe to each other. The duties we owe to each other depend on what kind of relationship we have.
Askeses – exercises of Stoic thought and practice that make the lessons and habits of Stoic philosophy second-nature for Stoic practitioners.
Externals – things that are not under our control but that are all-too-easily confused with things that should be important to us, like wealth, status, and pleasure. Too many people believe externals like these are necessary for the good life, and the Stoic path is to focus not on these things but rather what is up to us.
The Fundamental Division – the division between things that are under our direct control and those that are not. The important lesson is to care only about the things we can control.
The Greatest Happiness Principle – A principle which says that actions are right insofar as they promote happiness and wrong insofar as they promote unhappiness
Higher and Lower Pleasures – Types of pleasures that differ in terms of their quality. Things like food and drugs create lower pleasures. Things like intellectual pursuits and doing the right thing create higher forms of pleasure.
The Doctrine of Swine – An objection that utilitarianism entails that if people would be happy rolling in mud, that’s what would be morally best for them to do, so we should reject the theory.
Utilitarianism – A normative theory of which actions are right or wrong. Utilitarianism says the right action is that which maximises utility.
Jeremy Bentham – Considered by some as the father of utilitarianism, Bentham was a moral philosopher and one of John Stuart Mill’s teachers
Epicurus – an ancient Greek philosopher and one of the first to advocate that the ultimate good is experiencing pleasure and avoiding pain.
Utility – The thing that is ultimately valuable in itself. For Mill, this is happiness, which he then understands as pleasure and the absence of pain.
Contract Theory – a modern political theory identifying consent as the sole justification for government. Contract theory is associated with Thomas Hobbes (1588-1679), John Locke (1632-1704), Jean Jacques Rousseau (1712-1778), and more recently, John Rawls (1921-2002)
Prejudice – a foundational, strongly held, unreasoned (but not necessarily irrational) moral opinion or belief. We might believe, for example, that parents have special obligations towards their own children.
A Priori – a philosophical term of art meaning (in Latin) “prior to experience,” which refers to knowledge that is innate or arrived at purely through reasoning, like the truths of mathematics.
Rights – moral claims invoking immunity from (or entitlement to) some specific treatment (or good) from others. Commonly recognized rights include the right to free speech or the right to healthcare.
Reform – a change in the social order that originates from the existing character of society. An example would be market-based healthcare reform in a capitalist society.
Conservatism – a modern political ideology that aims to preserve and promote the existing (or traditional) institutions of society. These institutions typically include the rule of law, property, the family, and religion.
Contingent Being – A being that can fail to exist. Its existence is not guaranteed. This being might come to exist or it might not.
Necessary Being – A being that can’t fail to exist. Its non-existence is impossible. This also means that such a being has always existed.
Want to read more about why the infinite regress option doesn’t work in the Second Way? Check out Sean Floyd’s entry in the Internet Encyclopedia of Philosophy.
Efficient Cause – An efficient cause is something that directly makes another thing exist or move. An example of this is when I kick a ball down a hill. I am the efficient cause of the ball rolling down the hill because I make it move down the hill.
Infinite Regress: Begin with some fact. We begin to explain that fact by appealing to another fact, where these facts are related by either causality or dependence. To create the regress, you keep appealing to more and more facts about causality and dependence without end.
Actuality – An ability or action something is currently exercising. Imagine that I am sitting comfortably at my desk, and then I stand up to take a break from reading. In this case, I am now actually standing.
Potentiality – What something has the capacity to do, but isn’t currently doing. Imagine I am sitting comfortably at my desk. Even though I’m not currently standing, I have the capacity to be standing. So, even while I’m not standing, I have the potential to stand.
Theists and Non-Theists – A theist is someone who believes that God exists, while a non-theist does not. Non-theists include atheists, who believe that God does not exist, and agnostics, who are uncertain about whether God exists.
Glaucon – one of Plato’s brothers and one of Socrates’ main interlocutors in the Republic dialogue. In that dialogue, he challenges Socrates to provide a compelling justification for why one should be a just person beyond merely following conventions or avoiding punishment. This sets up Socrates’ defense of justice as intrinsically worthwhile. Throughout the Republic, Glaucon prods Socrates to fully explain his theories of the ideal society, philosopher-kings, and the Form of the Good.
Aristotle – a Greek philosopher (384-322 BC) who studied under Plato and went on to be one of the most influential philosophers to ever live. Simply called “The Philosopher” by Thomas Aquinas and others in the medieval period, Aristotle’s views would eventually be synthesized with Christian theology, laying the intellectual foundation for later scholarly developments in Western Europe.
Understanding – Socrates describes education as turning one’s “understanding” in the right direction. The word “understanding” here translates the ancient Greek term “to phronēsai,” which means “understanding,” “being conscious,” or “having insight.” People who are wicked focus their “understanding” on how best to accomplish their selfish and narrow desires. Those who are wise, in contrast, have learned to focus their “understanding” on what is truly good and beneficial.
The Form of the Good – Socrates characterizes the ultimate goal of education as coming to know “the Form of the Good.” The Form of the Good is his technical term for the meaning of goodness: what it is to be good. Socrates is clear that this “knowledge of the Good” is not simply theoretical knowledge, but also knowledge in the sense of “knowing how”: knowing how to achieve what’s good, to do what’s good, to accomplish what’s good. Mere “book knowledge” or simply being smart is not enough.
The Intelligible – Socrates uses “the intelligible” to name the aspects of the world that we can only grasp through thinking or insight. With my eyes I can see the tree outside my window, but what it means to be a tree is something I can only comprehend in thought. Likewise, I can see the people around me, but human nature, human dignity, and what it means to be human is something I can only grasp conceptually. “The intelligible” is the world insofar as it “makes sense” and can be comprehended.
The Visible – By “the visible,” Socrates means those aspects of the world we can perceive with our five senses and our imagination—those aspects of the world we can see, hear, taste, smell, touch, and imagine. For example, with my eyes I can see the sky, trees, people around me, and so on as visible things. “The visible” is the world insofar as it can be perceived and imagined.
Education – Socrates says that the allegorical story he tells represents the effect of education on human nature. “Education” here is a translation of the ancient Greek word “paideia,” which means “education” in the widest sense of the term. “Paideia” doesn’t mean “education” in the sense of going to school or getting good grades. Instead, it refers to the process of becoming a wise, intelligent, good, and well-rounded human being.
Allegory – An allegory is a symbolic narrative where characters, events, and/or settings represent abstract ideas or convey deeper meanings beyond the literal story. Socrates tells such a symbolic narrative in the passages below. The characters, events, and setting of his narrative symbolize the effect of what he calls “education.”
Self-knowledge – Knowledge of the contents of one’s own mind, such as one’s own beliefs and desires. Self-knowledge can be gained through introspection, that is, by reflecting on what one thinks and experiences. Some philosophers believe that self-knowledge has special properties that our knowledge of the external world lacks, such as being clearer, more reliable, or more valuable.
Dualism – The view that the mind is entirely distinct from the body. This view is usually contrasted with different kinds of monism, which hold that the mind is ultimately just a part of the body (materialism) or that the body is ultimately just a part of the mind (idealism). Dualists hold that the mind and the body are fundamentally different aspects of reality, and both categories are needed to properly describe the universe, especially the human person.
The Self – What the ‘I’ in ‘I am, I exist’ refers to; the part of you that really makes you you. Many philosophers have provided rich accounts of what the self ultimately is, including the soul, the mind, one special feature of the mind (such as consciousness), a mixture of all these elements, or perhaps a mere illusion.
The ‘Cogito’ – Descartes’ famous claim ‘I think, therefore I am’ is often referred to as the cogito. The name comes from the Latin rendering of this phrase, which is ‘cogito, ergo sum.’ Descartes held that one can always believe this proposition with certainty. We cannot doubt our own existence, so the cogito survives his exercise of intense doubt. The cogito appears several times in Descartes’ writings, and he often phrased it slightly differently each time. It appears in the Second Meditation as ‘I am, I exist.’
Certainty – When one believes something with certainty, one is maximally confident that it is true. A certainty is something that is beyond dispute or immune to doubt. Although this captures the basic idea, like many epistemological notions, clarifying precisely what the notion of certainty amounts to is an ongoing area of philosophical research.
Vice – A bad habit that we learn over time through instruction or instinct and that we develop through repetition. What makes the habit bad is that, once we have that habit, our tendency is to do the incorrect thing in certain types of situations. We may choose to do something entirely uncalled for in that situation, or we may act at the wrong time, in the wrong way, to the wrong degree, or with the wrong attitudes, or for the wrong reasons.
Relative Mean – The “Goldilocks amount” of some type of action or emotion. When you act in this way, according to Aristotle, you act exactly as is required under the current circumstances. This means that you do what is called for by the situation at hand, rather than doing something too extreme or not doing something extreme enough. You do something in the moderate amount (the mean amount) relative to the specific situation you are in when you need to act.
Excellence/Virtue – A good habit that we learn over time through instruction and repetition. What makes the habit good is that, once we have that habit, we have a strong tendency to do the right thing at the right time, in the right way, to the right degree, with the right attitudes, whenever we are confronted with a situation that we know calls us to exercise that habit.
