A priori
Knowledge of propositions that do not require (sense) experience to be known to be true or false.
A posteriori
Knowledge of propositions that can only be known to be true or false through sense experience.
Ability knowledge
Knowing ‘how’ to do something, e.g. ‘I know how to ride a bike’.
Abstract
Theoretical (rather than applied or practical) and removed from any concrete objects or instances.
Acquaintance knowledge
Knowing ‘of’ someone or some place. For example, ‘I know the manager of the restaurant’, or ‘I know Oxford well’.
Ad hoc
A statement or a move in an argument that suits the purpose at hand but has no independent support.
Analogy
Similarity in several respects between different things.
Analysis
Process of breaking up a complex concept, expression, or argument to reveal its simpler constituents, elucidating its meaning or logical structure.
Analytic
A proposition that is true (or false) in virtue of the meanings of the words. For instance, ‘a bachelor is an unmarried man’ is analytically true, while ‘a square has three sides’ is analytically false.
Antecedent
The proposition that forms the first part of a conditional statement, usually the part of the sentence that comes after ‘if’. E.g. in both ‘if it rains then I will get wet’ and ‘I will get wet if it rains’, the antecedent is ‘it rains’.
Anti-realism, moral
The theory that claims that there are no moral properties. Error theory and moral non-cognitivism are both anti-realist.
Applied ethics
The branch of ethics concerned with applying normative ethical theories to particular issues.
Arête
An 'excellence', or more specifically, a 'virtue' - a quality that aids the fulfilment of a thing's ergon (Aristotle).
Argument
A reasoned inference from one set of claims - the premises - to another claim, the conclusion.
Argument map
Visual diagram of the logical structure of an argument, i.e. how the premises logically relate to one another and to the conclusion.
Assertion
The claim that a proposition is true.
Assumption
A proposition accepted without proof or evidence as the basis for an inference or argument.
Attitude
A mental state regarding how the world is or should be. A cognitive attitude, e.g. belief, has a mind-to-world direction of fit. A non-cognitive attitude, e.g. desire, has a world-to-mind direction of fit.
Begging the question
The informal fallacy of (explicitly or implying) assuming the truth of the conclusion of an argument as one of the premises employed in an effort to demonstrate its truth.
Belief
Affirmation of, or conviction regarding, the truth of a proposition. E.g. ‘I believe that the grass is green’.
Cartesian circle
Refers to the circular reasoning Descartes seems to employ regarding clear and distinct ideas and God: ‘Descartes cannot rely on clear and distinct ideas before proving God exists, but he cannot prove that God exists without relying on clear and distinct ideas.
Categorical Imperative
Moral principle by Kant - 'Act only on that maxim through which you can at the same time will that it should become a universal law' (Kant).
Character
A person's habitual dispositions regarding what they feel, how they think, how they react, the choices they make, and the actions they perform, under different circumstances.
Character trait
An attribute exhibited by an individual as a matter of habit, e.g. honesty or being bad-tempered.
Choice
What we decide upon as a result of deliberation, typically giving rise to voluntary action. Deliberate desire regarding something that is in one’s power (Aristotle).
Circular
An argument is circular if it uses its conclusion as a premise.
Claim
A proposition asserted or affirmed to be true.
Clear and distinct ideas
A clear idea is ‘present and accessible to the attentive mind’; a distinct idea is a clear idea and also sharply separated from other ideas so that every part of it is clear (Descartes).
Cogent
An inductive argument where the truth of premises (significantly) raises the probability that the conclusion is true.
Cogito, the
Descartes' first certain knowledge - 'I think'.
Cognitivism
A cognitivist account of ethical language argues that moral judgements express beliefs, can be true or false, and aim to describe the world. So ‘lying is wrong’ expresses the belief that lying is wrong, and is either true or false.
Coherent
Set of statements are coherent if they are consistent and increase each other's probability.
Common sense
The basic perceptions or understandings that are shared by many (most) people.
Compatible
Two claims are compatible if they are consistent. Two properties are compatible if it is possible for something to have both of them at once.
Composition, fallacy of
The informal fallacy of attributing some feature if the members of a collection to the collection itself, or reasoning from part of a whole. E.g. ‘sodium and chloride are both dangerous to humans, therefore sodium-chloride (salt) is dangerous to humans’.
Concept
Any abstract notion or idea by virtue of which we apply general terms to things
Conclusion
A proposition whose truth has been inferred from premises.
Conditional
A proposition that takes the form of ‘if…, then…,’. This asserts that if the first statement (the antecedent) is true the second statement (the consequent) is also true. E.g. ‘If it is raining, then the ground is wet’ asserts that if it is raining, it is true that the ground is wet.
Conscience
An inner awareness, faculty intuition or judgement that assists in distinguishing right from wrong.
Consequent
The proposition that forms the second part of a conditional statement, usually the part of the sentence that occurs after ‘then’. E.g. In both ‘If it will rain then I will get wet’ and ‘I will get wet if it will rain’ the consequent is ‘I will get wet’.
Consequentialism, act
The theory that actions are morally right or wrong depending on their consequences and nothin else. An act is right if it maximises what is good.
Consistent
Two or more claims are consistent if they can both be true at the same time.
Contingent
A proposition that could either be true or false, a state of affairs that may or may not hold, depending on how the world actually is.
Contradiction
Two claims that cannot both be true, and cannot both be false. or one claim that both asserts and denies something. E.g. ‘It is raining and it is not raining’.
Contradiction in conception
In Kantian ethics, the test for whether we can will a maxima to become universal law can be failed if it would somehow be self-contradictory for everyone to act on that maxim.
Contradiction in will
In Kantian ethics, the test for whether we can will a maxima to become universal law can be failed if, although the maxim is not self-contradictory, we cannot rationally will it.
Copy principle, Humean
All simple ideas are copies of impressions.
Counter-argument
An argument that attempts to establish a conclusion that undermines another argument, or the conclusion of another argument.
Counterexamples, method of finding
If a theory makes a general claim, such as ‘all propositional knowledge is justified true belief’, we only need to find a single instance where this is false (a counterexample) to show that the general claim is false and there is something wrong with the theory.
Counter-intuitive
Something that doesn’t fit with our intuition
Deduction
An argument where the conclusion logically follows from the premises, meaning if the premises are true, the conclusion must be true.
Definition
An explanantion of the meaning of a word. Philosophical definitions often attempt to give necessary and sufficient conditions for the application of the term being defined.
Deontology
The study of what one must do (deon (Greek) means ‘one must’). Deontology claims that actions are right or wrong in themselves, not depending on their consequences. We have moral duties to do things which it is right to do and moral duties not to do things which it is wrong to do.
Desirable
1) Worthy of being desired. 2) Capable of being desired.
Desire
A state of mind that motivates a person to act in such a way as to satisfy the desire, e.g. if a person desires a cup of tea, they are motivated to make and drink a cup of tea.
Dilemma
Two mutually exclusive and exhaustive options (horns), both of which face significant objections.
Direct Realism
Physical objects exist independently of our minds and of our perception of them perceptions of them, and the immediate objects of perception are mind-independent objects and their properties.
Direction of fit
The direction of the relation between mind and world. In one direction, the mind ‘fits’ the world, as in belief. We change our beliefs to fit the facts. In the other direction, the world ‘fits’ the mind, as in desire. We act on our desires to change the world to satisfy our desires.
Disanalogy
A point of dissimilarity between two things, highlighting what they do not have in common.
Disjunction
An either/or claim. An example of a disjunction is: ‘Either it will rain or it will be sunny’.
Disjunctive theory of perception
If something looks a certain way, then one of two quite different things is going on: either I directly perceive a mind-independent physical object that is F or it appears to me just as if there is something that is F, but there is nothing that is F.
Doctrine of the Mean
Aristotle's claim that virtue requires us to feel, choose and act in an ‘intermediate’ way, neither ‘too much’ nor ‘too little’, but ‘to feel [passions] at the right times, with reference to the right objects, towards the right people, with the right motive, and in the right way’.
Duties, general/specific
Duties are obligation we have towards someone or something. General duties are those we have towards anyone, e.g. do not murder, help people in need. Specific duties are those we have because of our particular personal or social relationships, e.g. to keep one’s promises or to provide for one’s children.
Duties, Perfect/Imperfect
Perfect duties are those we must always fulfil and have no choice over when or how (e.g. do not kill). Imperfect duties are cases in which we have some choice in how we fulfil the obligation (e.g. giving to charity). No specific person can demand that we fulfil an imperfect duty towards them.
Emotivism
Theory suggesting that moral judgments express a feeling or non-cognitive attitude, typically approval or disapproval, and aim to influence the feelings and actions of others.
Empirical
Relating to or deriving from experience, especially sense experience, but also including experimental scientific investigation.
Empiricism
The theory that there can be no a priori knowledge of synthetic propositions about the world(outside my mind), i.e. all a priori knowledge is of analytic propositions, whilst all knowledge of synthetic propositions is gained through sense experience.
Empiricism, classical
The theory that all knowledge is gained from experience: All concepts are gained from sense experience or experience of our own minds; and all knowledge of synthetic propositions about the world (outside my mind) is gained through sense experience.
End
What an action seeks to achieve or secure, its aim or purpose.
End, final
An end that we desire for its own sake, we can’t give some further purpose for why we seek it.
Enumerative Induction
The method of reasoning that argues from many instances of something to a general statement about that thing. E.g. the sun has risen in the morning every day for x number of days, therefore the sun rises in the morning.
Epistemology
The study (-ology) of knowledge (episteme) and related concepts, including belief, justification, and certainty. It looks at the possibility and sources of knowledge.
Equivocation, fallacy of
The use of an ambiguous word or phrase in different senses within a single argument. E.g. ‘All banks are next to rivers, I deposit money in a bank, therefore I deposit money next to a river’.
Ergon
The ‘function’ or ‘characteristic activity’ of something, e.g. the ergon of a knife is to cut, the ergon of an eye is to see.
Error Theory
The belief that moral judgments make claims about objective moral properties, but that no such properties exist. Thus moral judgements are cognitive, but are all false. Moral language, as we mean to use it, rests on a mistake.
Ethics
A branch of philosophy concerned with the evaluation of human conduct, including theories about which actions are right or wrong (normative ethics) and the meaning of moral language (meta ethics).
Eudaimonia
Often translated as 'happiness’, but better understood as ‘living well and fairing well’. According to Aristotle, eudaemonia is not subjective and is not a psychological state, but an objective quality of someone’s life as a whole. It is the final end for human beings.
Experience Machine
Nozick's thought experiment concerning a virtual reality machine which someone plugs into for life. The machine will create the experience of a very happy life, but Nozick argues that we value being in touch with reality more, so we won’t choose to plug in.
Explanation
An intelligible account of why something happens. The thing to be explained (the explanandum) is usually accepted as a fact, and wha tis used to explain it (the explanans) is usually the plausible but less certain.
External world
Everything that exists outside of our minds.
Faculty
A mental capacity or ability like sight, the ability to fear, and reason.
Fallacy/fallacious
An error in reasoning. More exactly, a fallacy is an argument in which the premises do not offer rational support to the conclusion. If the argument is deductive, then it is fallacious if it it not valid. If the argument is inductive, it is fallacious if the premises do not make the conclusion more likely to be true.
False
A proposition is false if things are not as it states. E.g. the proposition ‘grass is always purple’ is false, because there is grass that is not purple.
Felicific calculus
In Bentham’s ethics, the means of calculating pleasure and pains caused by an action and adding them up on a single scale. The total amount of happiness produced is the sum total of everyone’s pleasures minus the sum total of everyone’s pains.
First principles
Basic or foundational propositions in an area of knowledge or theory that are not deducible from other propositions.
Formula of Humanity
A version of the Categorical Imperative: ‘Act in such a way that you always treat humanity, whether in your own person or in the person of any other, never simply as a means, but always at the same time as an end’ (Kant).
Function argument
Aristotle’s argument that the human good (eudaimonia) will be achieved by performing our characteristic activity (ergon) well. Traits that enable us to fulfil our ergon, which is rational activity, are virtues (arête).
Gettier case
A situation in which we have justified true belief, but not knowledge, because the belief is only accidentally true, given the evidence that justifies it.
Golden Rule
Moral guideline that says ‘do unto others as you would have them do unto you’.
Good
In ethics, what is good provides a standard evaluation and what we should aim at in our actions and lives.
Hallucination
A non-veridical perceptual experience that is not coherently connected with the rest of our perceptual experience.
Hallucinaiton, argument from
Against direct realism: The possibility of hallucinatory experiences that are subjectively indistinguishable from a veridical perseption means that we don’t immediately perceive physical objects, but sense-data.
Hedonic calculus
See felicific calculus, a method to calculate pleasure and pain.
Hedonism
The claim that pleasure is happiness and the only good.
Hume's 'fork'
We have knowledge of just two sorts of claim: the relations between ideas and matters of fact.
Hypothesis
A proposal that needs to be confirmed or rejected by reasoning or experience.
Hypothetical reasoning
Working out the best hypothesis that would explain or account for some experience or fact.
Idea
An object of perception, thought, or understanding. Locke uses the term to refer to a complete thought, taking the form of a proposition, e.g. ‘bananas are yellow’; a sensation or sensory experience, e.g. a visual sensation of yellow, or a concept, e.g. YELLOW.
Idea, complex
An idea that is derived from two or more simple ideas
Idea, simple
A single, uniform conception, with nothing distinguishable within it.