Philosophy

Epistemology: Concept of Knowledge, Morality and Ethics: Utilitarianism

A posteriori

Knowledge that can only be acquired from experience of the external world. For example, there is no way you could work out what temperature water boils at purely by thinking. You’d have to have experience of the external world to know the answer.

A priori

Knowledge that can be acquired without experience of the external world, through thought alone. For example, you can work out what 900 divided by 7 is purely by thinking – you don’t need experience of the external world to verify it.

Abductive argument

A form of inductive argument which shows says that something is probably true because it is the best explanation. An explanation might be considered better than alternatives due to its explanatory and predictive power, or because it makes the fewest assumptions (a principle known as Ockham’s razor)

Ability knowledge

Knowledge of how to do something. For example, knowing how to ride a bike or how to juggle.

Acquaintance knowledge

Knowledge of something or someone. For example, “I know James well” or “I know Berlin well”.

Analytic reduction

If X analytically reduces to Y, then the meaning of X is the same as the meaning of Y. For example, “triangle” analytically reduces to “3-sided shape” because the meaning of “triangle” is “3 sided shape”.

Analytic truth

A proposition that is true in virtue of the meaning of the words. For example, “A bachelor is an unmarried man” or “triangles have 3 sides” or “1+1=2”. Denying an analytic truth results in a logical contradiction. For example, the idea of a married bachelor or a 4-side triangle is a contradiction – it doesn’t make sense.

Cognitive statement

Cognitive statements aim to literally describe how the world is and are either true or false. For example, “water boils at 100°c” , “triangles have 3 sides”, “Paris is the capital of France”, and “London is the capital of France” are all cognitive statements because they are capable of being true or false.

Consequentialist

An ethical theory that values as actions as good or bad according to their consequences. For example, utilitarianism is a consequentialist ethical theory.

Contingent truth

Something that is true but that might not have been true. For example, “Paris is the capital of France” is a contingent truth because they could have made Lyon the capital instead. Even “water boils at 100°c” is a contingent truth because the laws of physics could have been different.

Contradiction

Two claims contradict one another if they cannot both be true simultaneously. For example, “today is Monday” contradicts the claim “today is not Monday”.

Deduction

A method of deriving true propositions from other true propositions (using reason and logical necessity). It is an a priori method of gaining knowledge.

Deductive argument

An argument where the premises are intended to logically guarantee the conclusion (i.e. an argument that is intended to be logically valid). For example, the logical problem of evil is supposed to logically guarantee the conclusion “God does not exist” whereas an inductive argument such as the evidential problem of evil is only supposed to provide evidence to supports its conclusion.

Direct realism

The view that a mind-independent external world exists and that we perceive it directly.

(Ordinary) Doubt

Being unsure whether something in your everyday life is true. For example, you might doubt whether you locked the door when you left the house and so doubt whether your belief “I locked the door” is true.

(Philosophical) Doubt

Being unsure whether anything you believe is true. For example, you might doubt your perceptions and your own thoughts (and thus any beliefs formed from them) because of the possibility of global sceptical scenarios.

Fallacy

The use of invalid or otherwise faulty reasoning.

Gettier case

An example of a justified true belief that is not knowledge. Gettier cases thus show that the tripartite definition of knowledge does not provide sufficient conditions for knowledge.

Idealism

The view that there is no such thing as a mind-independent external world and that what we perceive are mind-dependent ideas.

Indirect realism

The view that a mind-independent external world exists, but that we perceive it indirectly via sense data. This sense data is caused by and represents the mind-independent external world.

Inductive argument

An argument where the premises support the conclusion, but don’t logically guarantee it. For example, the evidential problem of evil is supposed to provide good evidence for the conclusion “God does not exist”. However, unlike a deductive argument, an inductive argument does not logically guarantee its conclusion.

Infallibilism

The definition of knowledge as true belief that is certain. According to infallibilism, anything that can be doubted is not knowledge. For example, on the infallibilist definition, I can’t know “grass is green” because I might be being deceived by an evil demon.

Invalid argument

An argument where it’s possible for the premises to be true but the conclusion be false. For example, even though 1, 2, and 3 below are true, the following argument is invalid:
1. If Socrates is a man, then Socrates is a mortal
2. Socrates is a mortal
3. Therefore, Socrates is a man
Even though both premises (1 and 2) are true, and the conclusion (3) is also true, this argument is not valid because it’s possible for the premises to be true and the conclusion to be false. For example, if Socrates was the name of my cat, then premise 2 (Socrates is a mortal) would still be true but the conclusion (Socrates is a man) would be false.

Moral realism

The metaethical view that that mind-independent moral properties (e.g. good, bad, right, and wrong) and facts exist.

Moral anti-realism

The metaethical view that that mind-independent moral properties (e.g. good, bad, right, and wrong) and facts do not exist.

Necessary condition

A condition that something must meet to be part of a concept. In other words, if anything that does not have this condition it will not be part of that concept. For example, “unmarried” is a necessary condition of “bachelor” because you have to be unmarried to fit the concept of a bachelor.

Necessary truth

Something that must be true (in all possible worlds). For example, “1+1=2” and “it is impossible for both a and not a to be true” are necessary truths because there is no possible world in which they are false.

Non-cognitive statement

Non-cognitive statements do not aim to describe how the world is and so are not capable of being either true or false. For example, “ouch!”, “boo!”, “hooray!”, “don’t do that!”, and “shut the door please” are all examples of non-cognitive statements because they are not capable of being true or false.

Ockham’s razor

The principle that if two theories have the same explanatory and predictive power, the theory that invokes the fewest entities is usually the better one. In other words, the simplest explanation is the best (all else being equal).

Propositional knowledge

Knowledge that something is true. For example, “I know that London is the capital of England.”

Rationalism

The view that there are some synthetic truths that can be known purely through a priori means. For example, Descartes’ cogito argument attempts to prove the synthetic truth “I exist” using thought alone and without reference to the external world.

Realism

Realist theories claim that certain kinds of mind-independent entities exist. In metaethics, for example, moral realism claims that mind-independent moral properties exist. And in knowledge from perception, direct realism and indirect realism claim that mind-independent objects exist.

Sound argument

A valid argument with true premises (and thus a true conclusion).

Sufficient conditions

Conditions that, if all are met, guarantee that something is part of a concept. For example. “unmarried” and “man” are sufficient conditions of “bachelor” because everything that is an unmarried man is a bachelor. Being an unmarried man is sufficient to be a bachelor – you don’t need to meet any other conditions.

Synthetic truth

A proposition that is true in virtue of how the world is. For example, “grass is green” or “water boils at 100°c”. Unlike an analytic truth, denying a synthetic truth does not lead to a logical contradiction. For example, even though “grass is green” is true, there is no logical contradiction in the idea of red grass. The idea of red grass makes sense, even if it is not how the world actually is.

Tripartite definition of knowledge

The definition of (propositional) knowledge as justified true belief.

(Act) Utilitarianism

The ethical theory that happiness is good and that morally correct actions are those that maximise happiness and minimise pain.

(Rule) Utilitarianism

The ethical theory that happiness is good and that we should follow general rules that maximise happiness and minimise pain (even though there may be specific instances where following these rules does not maximise happiness).

(Preference) Utilitarianism

The ethical theory that morally correct actions are those that maximise people’s preferences.

Valid argument

An argument where if the premises are true, the conclusion must also be true. For example, it is logically impossible for 1 and 2 below to be true but 3 be false:
1. If Socrates is a man, then Socrates is a mortal
2. Socrates is a man
3. Therefore, Socrates is a mortal
Note: A valid argument does not necessarily mean the conclusion is true. Even though the logic of the argument may be valid, the premises (and thus the conclusion) may be false.

Necessary and Sufficient conditions

In philosophy, a necessary condition is something that must be true for another thing to be true—without it, the other cannot occur. A sufficient condition is something that, if true, guarantees the truth of another thing. For example, being a bachelor is a sufficient condition for being unmarried, but being unmarried is only a necessary condition for being a bachelor.

Truth condition

A belief counts as knowledge only if it is true. This means the proposition believed must correspond to reality or facts.

Belief condition

To know something, a person must believe it. Without belief, even a true proposition cannot be considered knowledge.

Justification Condition

A belief counts as knowledge only if it is justified. This means the person must have good reasons or evidence to support the belief, not just a lucky guess.

Epistemic luck

Epistemic luck occurs when someone arrives at a true belief by chance, without proper justification. It undermines knowledge because the truth was not reached through reliable reasoning.

Reliabilism

Reliabilism is the theory that a belief counts as knowledge if it is produced by a reliable cognitive process—one that usually leads to truth, like perception or memory.

Virtue Epistemology (Zagzebski)

Zagzebski defines knowledge as a belief that is true, motivated by intellectual virtue, and formed through good character traits like honesty or courage in inquiry.

Virtue Epistemology (Sosa)

Sosa argues that knowledge is a true belief formed through intellectual virtue—like perception or reasoning—that reliably leads to truth. It’s like hitting a target because of skill, not luck.

Non-false-lemmas

Knowledge must not be based on any false assumptions or beliefs. A person knows something only if their justification doesn’t rely on a false lemma—a mistaken step in reasoning.

Hedonistic utilitarianism

Hedonistic utilitarianism holds that pleasure is the only intrinsic good. An action is right if it maximizes pleasure and minimizes pain for everyone affected.

Quantative utilitarianism

Quantitative utilitarianism judges actions by the amount of pleasure they produce. It focuses on measuring happiness in terms of intensity and duration, not quality.

The Utility Principle

The Utility Principle states that actions are morally right if they promote the greatest happiness for the greatest number. It’s the core idea behind utilitarian ethics.

Tyranny of the Majority

A criticism of utilitarianism where the happiness of the majority can justify harming a minority. It shows how majority rule can override individual rights.

Qualitative utilitarianism

Mill’s version of utilitarianism that values the quality of pleasures, not just quantity. Higher pleasures of the mind are considered more valuable than lower bodily pleasures.

Higher and Lower pleasures 

Mill distinguishes between intellectual pleasures (higher) and physical pleasures (lower). He argues that higher pleasures are more fulfilling and should be prioritized.

Fallacy of equivocation

This fallacy occurs when a word is used with different meanings in an argument, misleading the conclusion. It exploits ambiguity in language.

Fallacy of composition

This fallacy assumes that what is true of the parts must be true of the whole. It wrongly generalizes from individual cases to a collective.

Naturalistic fallacy

Coined by G.E. Moore, it’s the mistake of defining “good” in terms of natural properties like pleasure. It argues that moral terms can’t be reduced to natural facts.

Non-hedonic utilitarianism

A form of utilitarianism that values things other than pleasure, such as preference satisfaction or ideal outcomes. It broadens the idea of what counts as utility.

Moral integrity

Bernard Williams argues that utilitarianism can violate personal moral integrity by forcing individuals to act against their deepest values for the greater good.

Coherence theory

A belief is true if it fits consistently within a system of beliefs. Truth depends on logical coherence with other accepted propositions.

Correspondence theory

A belief is true if it matches reality. Truth is a matter of a proposition accurately reflecting the way the world actually is.