Naming and Necessity

1. Introduction

Naming and Necessity is a short but highly influential work in analytic philosophy in which Saul A. Kripke proposes a new framework for understanding reference, modality, and identity. First delivered as three lectures at Princeton University in 1970, the work challenges mid‑20th‑century orthodoxies in the philosophy of language and logic, especially descriptivist accounts of proper names and the identification of necessity with a priori truth.

At the center of the book are three interconnected ideas:

• a distinctive account of how proper names and certain general terms refer;
• the notion of rigid designation, applied to both names and natural kind terms;
• an articulated separation of the epistemic contrast between a priori / a posteriori and the modal contrast between necessary / contingent.

Kripke develops these ideas through informal argument, modal reasoning with possible worlds, and a series of detailed thought experiments rather than through a formal semantic system. The lectures are explicitly corrective and reconstructive: they take aim at what Kripke presents as the “Frege–Russell” tradition, as later developed by Carnap and others, and they reconfigure debates about identity statements such as “Hesperus is Phosphorus” and scientific identifications like “Water is H2O”.

The work has been interpreted both as a contribution to technical debates in philosophy of language and as part of a broader metaphysical turn within analytic philosophy. Subsequent sections of this entry examine its historical background, internal structure, core arguments, and the extensive critical literature it generated.

2. Historical and Philosophical Context

Naming and Necessity emerged within a philosophical landscape shaped by Frege, Russell, Wittgenstein, and logical empiricism, as well as by post‑Quinean debates about analyticity and modality. Kripke’s lectures intervene in several live controversies of the 1950s–1960s.

Background in Philosophy of Language

A dominant view in early analytic philosophy held that proper names are associated with senses or descriptive conditions that determine their reference. Frege distinguished between sense and reference; Russell treated ordinary proper names as disguised descriptions; and later “cluster” theories (inspired by Wittgenstein and developed by Searle and others) tied a name to a family of descriptions commonly associated with its bearer. By the late 1960s, such descriptivist approaches were widely regarded as the default.

Modal Logic and Possible Worlds

In logic and metaphysics, modal notions of necessity and possibility had become more technically tractable through the development of possible‑world semantics by Kripke and others. However, philosophers influenced by Quine remained suspicious of quantified modal logic and de re modality, worrying about essentialism and reference across possible worlds. Carnapian and other conventionalist treatments often identified the necessary with the analytic or a priori.

Key Currents Shaping the Work

Within this context, Kripke’s lectures have been read as part of a broader shift away from strict verificationism and toward a more robust metaphysics and semantics, while still employing the tools of analytic philosophy.

3. Author and Composition of the Lectures

Saul A. Kripke (b. 1940) is an American philosopher and logician whose work spans modal logic, set theory, philosophy of language, and metaphysics. Already known for foundational contributions to modal and intuitionistic logic in his teens and early twenties, Kripke was a central figure in the technical development of possible‑world semantics before turning, in Naming and Necessity, to its philosophical implications.

Academic Setting and Intellectual Development

At the time of the Naming and Necessity lectures, Kripke had held positions at institutions including Rockefeller University and Princeton University. His earlier logical work on modal semantics, truth, and necessity provided both the formal backdrop and many of the conceptual tools that inform the lectures, although the lectures themselves are deliberately non‑technical.

Kripke’s engagement with Frege, Russell, Wittgenstein, Carnap, and Quine is evident throughout. He draws on:

• Frege’s distinction between sense and reference;
• Russell’s theory of descriptions;
• Wittgensteinian themes about language use and rule‑following;
• Carnap’s views on analyticity and theoretical terms;
• Quine’s doubts about modality and essentialism.

Composition and Style of the Lectures

The three lectures were delivered at Princeton in January 1970 as part of the “Princeton Lectures” series. Kripke worked largely without a full written text, relying on detailed notes and an informal, conversational style. This lecture format shapes the published work: the arguments often unfold dialectically, addressing anticipated objections from an audience familiar with mid‑century analytic orthodoxy.

Kripke subsequently expanded, clarified, and lightly edited the lectures for publication, but retained much of their oral character, including digressions, rhetorical questions, and examples drawn from everyday language. Commentators often emphasize this combination of technical background and informal exposition as distinctive of the work’s composition and authorial voice.

4. Publication History and Textual Status

The textual history of Naming and Necessity involves an initial lecture series, journal publication, and later book‑form revision. The work’s canonical status is tied to the 1980 Harvard University Press edition, though philosophers sometimes distinguish carefully between the 1970 lectures, the 1972 articles, and the book.

Chronology of Publication

The 1972 Synthese version made the content widely accessible within the philosophical community, but it remained textually close to the lectures. The 1980 book adds a preface, minor clarifications, and notes, but does not systematically reformulate the arguments. Scholars often regard the book as the standard edition.

Textual Status and Variants

Kripke’s own notes and drafts are not widely published, but there is no complex manuscript tradition; the work survives in a stable, authorially approved form. The 1980 text is generally treated as definitive for citation and interpretation.

Some differences between the 1972 and 1980 versions—such as elaborations of certain examples, added references, and clarifying remarks—have been discussed in the secondary literature, especially where they bear on interpretive questions about Kripke’s commitments. Nonetheless, there is broad agreement that the core theses and arguments are consistent across the different published forms.

Translations into multiple languages have further disseminated the text. While minor translational issues have been noted, especially around terms like “rigid designator” or “essence,” there is no widely recognized alternative textual tradition competing with the Harvard edition.

5. Structure and Organization of Naming and Necessity

Naming and Necessity is organized around three lectures, followed by a brief preface and notes in the 1980 book edition. Each lecture has a distinct thematic focus, while arguments and examples recur across them to build an integrated picture of reference and modality.

Overall Layout

Internal Organization of the Lectures

Within each lecture, Kripke proceeds informally rather than by numbered sections, but distinct argumentative phases are recognizable.

• Lecture I moves from a survey of descriptivist theories of names, through counterexamples (including famous thought experiments), to a sketch of an alternative causal‑historical account of naming and reference.
• Lecture II refines the notion of a rigid designator, applies it to identity statements involving names and descriptions, and explores how this interacts with possible worlds semantics and with the necessary/contingent vs a priori/a posteriori distinctions.
• Lecture III extends the semantic framework to natural kind terms, discusses the status of scientific identifications and essential properties, and then uses these tools to examine, and ultimately challenge, mind–brain identity theories.

The structure thus moves from a focus on proper names, to a broader modal and semantic framework, to applications in metaphysics and philosophy of mind. The notes and preface in the 1980 edition supply limited cross‑references and acknowledgements but do not significantly alter this three‑part organization.

6. Critique of Descriptivist Theories of Names

A central component of Naming and Necessity is Kripke’s systematic critique of descriptivist accounts of proper names. These accounts, associated with Frege, Russell, and later “cluster” theorists, treat a name as synonymous with a description or as referring to whatever uniquely satisfies a description known by competent speakers.

Target Theories

Kripke distinguishes several forms:

These are reconstructed as dominant tendencies, not always as precise doctrines held by particular authors.

Main Lines of Criticism

Kripke formulates several conditions that a descriptivist theory should satisfy (such as correctness of reference, knowledge by competent speakers, and necessity of associated descriptions) and argues that they cannot all be met simultaneously.

Key objections include:

• Modal argument: Descriptivism incorrectly predicts that certain identity statements involving names would be necessary if true (since they would reduce to analytic descriptions), whereas they seem contingent.
• Epistemic argument: If a name were synonymous with a description known a priori, identity claims like “Hesperus is Phosphorus” should be knowable a priori, contrary to intuition and scientific practice.
• Ignorance and error cases: Speakers can successfully use a name while being ignorant of, or mistaken about, most associated descriptions (e.g., attributing the wrong discoveries to “Gödel”), suggesting that descriptive knowledge is neither necessary nor sufficient for reference.

Proponents of descriptivism have responded by refining their accounts, weakening the requirement that associated descriptions be known a priori, or introducing causal and social elements. Kripke’s critique is widely credited with shifting the burden of proof toward such non‑purely‑descriptivist or hybrid theories.

7. Causal-Historical Reference and Baptism

In place of descriptivism, Naming and Necessity sketches a causal‑historical account of how proper names refer. Kripke does not present this as a fully articulated theory, but as a broadly outlined alternative that better fits ordinary linguistic practice and modal reasoning.

Initial “Baptism” or Dubbing

According to Kripke’s picture, the reference of a name is fixed in an initial act of baptism:

• An object (person, place, or thing) is singled out, perceptually or via description.
• A name is introduced with the intention that it refer to that object.
• A reference‑fixing description may be used at this stage (“Let ‘Gödel’ name the man who discovered the incompleteness theorem”), but this description does not become the meaning of the name.

The baptism establishes a link between the name and its bearer in the actual world.

Causal Chain of Transmission

After baptism, the name is passed from speaker to speaker through communicative interactions:

• Later users intend to use the name with the same reference as those from whom they learned it.
• This generates a historical chain of uses tracing back (typically) to the original baptism.

On this view, a competent speaker need not associate any particular correct descriptive information with the name; successful reference depends instead on standing in the right causal‑historical relation to the initial dubbing.

Scope and Limitations

Kripke emphasizes that this picture is not a denial that descriptive information plays a role in practice; such information often guides the initial baptism and helps identify which causal chain one participates in. However, he argues that the causal‑historical framework better explains persistence of reference through error and change of beliefs, and underwrites later claims about rigid designation and cross‑world identity. Critics have contended that the account underplays the role of cognitive and contextual factors, leading to various hybrid or two‑factor theories.

8. Rigid Designation and Modal Reasoning

A distinctive contribution of Naming and Necessity is the introduction and systematic use of the notion of a rigid designator. This concept structures Kripke’s modal reasoning about identity and underlies his treatment of names and certain general terms.

Definition and Contrast

Kripke defines:

• A rigid designator as an expression that designates the same object in every possible world in which that object exists, and never designates anything else.
• A non‑rigid (flaccid) designator as an expression whose referent may vary across possible worlds.

Paradigmatically, proper names (e.g., “Aristotle”) are presented as rigid, while many definite descriptions (e.g., “the teacher of Alexander the Great”) are non‑rigid, since they might pick out different individuals in different possible scenarios.

Identity and Necessity

Kripke argues that if an identity statement of the form “a = b” is true and both “a” and “b” are rigid designators, then the identity holds in every possible world where the referent exists; hence, it is necessary. This contrasts with identity statements involving non‑rigid designators, which may be contingently true.

This reasoning uses possible worlds as a heuristic to talk about counterfactual situations, not as concrete entities.

De Re and De Dicto

Rigid designation also clarifies the distinction between de re and de dicto modality. De re claims concern what a particular object is or could have been; de dicto claims concern what some description or sentence could have been true of. Kripke maintains that rigid designators enable clear de re modal claims (e.g., that this very person might have had different properties), whereas non‑rigid descriptions often support only de dicto readings.

Subsequent debates have explored whether all proper names are rigid in Kripke’s sense, how to treat demonstratives and indexicals, and whether certain definite descriptions can be used rigidly by stipulation.

9. Necessary A Posteriori and Contingent A Priori

Naming and Necessity challenges the traditional alignment of modality with epistemology by arguing that the necessary/contingent distinction is independent of the a priori/a posteriori distinction. Kripke introduces two controversial categories: the necessary a posteriori and the contingent a priori.

Necessary A Posteriori

Kripke maintains that some truths are metaphysically necessary yet knowable only through empirical investigation. Examples (discussed in detail in the text) involve identity statements between rigid designators, such as certain astronomical or scientific identifications. These are:

• necessary: true in every possible world where the relevant entities exist, given their identity and rigid designation;
• a posteriori: discovered through observation and scientific reasoning, not through armchair conceptual analysis.

This undermines the view, associated with logical empiricism and some interpretations of Kant, that all necessary truths are a priori.

Contingent A Priori

Conversely, Kripke argues that there can be truths that are knowable a priori yet metaphysically contingent. Typical cases involve stipulative reference‑fixing:

• A speaker introduces a term by stipulation (“Let ‘meter’ denote the length of this stick at time t0”).
• The resulting sentence (“The length of this stick at t0 is one meter”) can be known a priori by anyone who understands the stipulation.
• Nevertheless, in other possible worlds the stick might have had a different length at t0, making the sentence metaphysically contingent.

Critics have questioned whether the purported contingent a priori cases are genuinely a priori or genuinely contingent, and whether the necessity in Kripke’s necessary a posteriori examples is metaphysical, semantic, or conceptual. Nonetheless, the separation of the two distinctions has become a standard framework for later debates.

10. Natural Kinds, Essence, and Scientific Identities

In the third lecture, Kripke extends his semantic and modal framework from proper names to certain general terms, particularly natural kind terms such as “water”, “gold”, and “tiger”. He connects these to questions of essence and the status of scientific identifications.

Natural Kind Terms as Rigid Designators

Kripke proposes that natural kind terms function, in important respects, like rigid designators:

• They refer to a certain natural kind in the actual world (e.g., the liquid with a particular microstructural composition).
• In other possible worlds, the same term picks out that same kind wherever it exists, even if its superficial properties differ (e.g., water might not be transparent or potable, but would still be H2O).

This contrasts with descriptions like “clear, drinkable liquid in lakes and rivers”, which are non‑rigid and might be satisfied by different substances in different possible worlds.

Essence and Underlying Structure

Kripke associates natural kinds with essential properties, typically understood as underlying microstructural features:

• For water, the essence is something like being H2O.
• For gold, it is having atomic number 79.
• For a biological species, it may involve genetic or biological structure.

He suggests that once the actual‑world essence is discovered empirically, it constrains what counts as the same kind in counterfactual situations.

Scientific Identities

On this view, scientific discoveries often yield necessary a posteriori identities, such as statements linking macroscopic phenomena to microstructural features (e.g., schematic “water is H2O”, “gold is the element with atomic number 79”). Kripke treats such identifications as true in all possible worlds where the kind exists, though discoverable only empirically.

Debates have arisen over whether natural kind terms really behave as rigid designators, whether essences should be understood microstructurally, and how this picture accommodates scientific change and theoretical revision. Alternative accounts, including more pragmatist or non‑essentialist views, interpret natural kind terms and scientific identities in less metaphysically demanding ways.

11. Names, Belief Reports, and Cognitive Significance

Naming and Necessity also addresses the interaction between Kripke’s account of names and traditional puzzles about belief reports and cognitive significance. These issues arise because co‑referential names can differ in how they present their referent to a thinker.

Substitution in Attitude Contexts

On a Millian or direct‑reference view (which Kripke’s framework tends to support), the semantic contribution of a name to the truth conditions of a sentence is just its referent. However, in propositional attitude reports, such as belief ascriptions, simple substitution of co‑referential names can seem to change truth‑value. Kripke revisits familiar examples, including variants of cases where a person believes of an individual under one name but not under another co‑referring name.

These cases raise questions about:

• whether belief contents are fine‑grained in a way that goes beyond reference;
• how to reconcile rigidity and direct reference with differences in cognitive significance.

The Paderewski Case and Related Puzzles

One of Kripke’s well‑known illustrations involves a subject who has two distinct sets of beliefs associated with the same name (e.g., “Paderewski”), mistakenly thinking they concern different individuals. The subject might endorse:

• “Paderewski was a great pianist” (using the name under one associated dossier);
• “Paderewski was not a great pianist” (using the same name under another).

This suggests that treating names simply as rigid designators for belief‑report semantics may be insufficient to capture intuitive differences in belief and rationality.

Kripke does not develop a full alternative theory of belief reports or sense, but he argues that the problems raised by such cases do not undermine the core claims about reference and rigidity. Later philosophers have built on these discussions to devise more elaborate accounts of propositions, modes of presentation, and the semantics of attitude ascriptions.

12. Kripke’s Argument Against Mind–Brain Identity

In the third lecture, Kripke applies his modal and semantic framework to the mind–brain identity theory, which holds that mental states (such as pain) are identical with physical brain states. His discussion is not a comprehensive philosophy of mind, but an argument that standard identity‑theoretic claims face distinctive difficulties if one accepts rigid designation and necessary a posteriori identities.

Structure of the Argument

Kripke assumes, in line with his earlier claims, that:

• If an identity statement between rigid designators is true (e.g., “water = H2O”), it is metaphysically necessary.
• Terms for mental states (e.g., “pain”) and terms for physical states (e.g., “C‑fiber firing”) can be treated as rigid designators, each referring to the same kind of state in every possible world where they exist.

Given this, a true mind–brain identity statement would be necessarily true if true at all.

Intuitions About Possibility

Kripke then appeals to certain modal intuitions:

• It seems possible to have pain without the corresponding physical state (e.g., to feel pain without C‑fiber firing).
• It also seems possible to have the physical state without the associated conscious experience (e.g., a “zombie” or unconscious subject with C‑fiber firing but no pain).

Proponents of the identity theory might interpret these as epistemic possibilities (reflecting ignorance) rather than metaphysical ones. Kripke contends, however, that unlike some scientific identifications (such as those for heat or water), our concepts of mental states are such that genuine pains necessarily involve their characteristic phenomenal feel.

Interpretations and Responses

Kripke’s argument has been interpreted in various ways: as challenging physicalist identity theories specifically, as raising issues about phenomenal concepts, or as relying on particular views about conceivability and necessity. Critics have questioned whether the relevant intuitions track metaphysical possibility, whether mental terms are rigid in the required sense, and how to distinguish Kripke’s treatment of mind–brain identities from his acceptance of necessary a posteriori scientific identities.

The discussion has been central to subsequent debates in the philosophy of mind, particularly regarding physicalism, qualia, and the explanatory gap.

13. Key Thought Experiments and Famous Passages

Naming and Necessity is notable for its use of vivid thought experiments and memorable examples to motivate theoretical claims. Several have become standard reference points in subsequent literature.

Representative Thought Experiments

These cases are designed to elicit intuitive judgments about reference, modality, and knowledge, which Kripke then uses as data for and constraints upon theory construction.

Famous Passages and Formulations

Some passages are frequently quoted, both for their doctrinal importance and stylistic impact. For instance, Kripke’s characterization of rigid designation and his remarks on the necessary a posteriori have been widely cited. A typical formulation runs:

"

A rigid designator of an object is a term that designates that same object in every possible world in which that object exists.

— Saul A. Kripke, Naming and Necessity (1980 ed.)

Other well‑known sections include his extended discussion of the Gödel case, his comparison of different types of identity statement, and his remarks on the role of intuitions in philosophy. These thought experiments and passages serve as focal points in the secondary literature, often being re‑interpreted, modified, or challenged to test the robustness of Kripke’s conclusions.

14. Philosophical Method and Use of Intuitions

Kripke’s methodological stance in Naming and Necessity combines technical background in logic with an informal, example‑driven style and a prominent role for intuitive judgments about possibility, reference, and language use.

Appeal to Ordinary Language and Intuitions

Kripke repeatedly emphasizes the importance of how speakers actually use names and modal expressions, and he treats speakers’ intuitive verdicts about counterfactual scenarios as serious data. For example, he invites the audience to consider whether it is “really” possible that a given person might not have had certain properties, or whether a name would still refer to the same individual in alternative circumstances.

These intuitions function as:

• constraints on acceptable semantic and metaphysical theories;
• evidence against descriptivist or purely stipulative treatments of reference and necessity.

Possible Worlds as Heuristic

While Kripke is a major figure in formal modal logic, Naming and Necessity uses possible worlds in a primarily informal and metaphysical way. Worlds are introduced as ways things might have been, not as abstract entities with a fully regimented ontology. This allows modal reasoning to proceed through descriptive scenarios, rather than via formal derivations.

Relation to Analytic Traditions

Kripke’s method differs from both strict logical empiricism (with its emphasis on formal reconstruction and verification) and some versions of ordinary‑language philosophy (with their anti‑theoretical tendencies). His approach has been seen as part of a broader “armchair” methodology in analytic metaphysics, balancing respect for intuitive data with systematic theory building.

Critics have questioned the reliability and universality of the intuitions on which he relies, leading to methodological debates about conceptual analysis, thought experiments, and the evidential status of modal judgments.

15. Major Criticisms and Ongoing Debates

Since its publication, Naming and Necessity has generated extensive critical discussion. Debates concern both the details of Kripke’s proposals and their broader philosophical implications.

Reference and Descriptivism

Critics of the causal‑historical picture argue that:

• it underplays the role of speaker intentions, context, and associated descriptions in successful reference;
• it struggles with cases of reference change, empty names, or reference to abstract objects.

In response, various hybrid theories integrate causal chains with descriptive or cognitive components, while some philosophers defend refined forms of descriptivism compatible with aspects of Kripke’s critique.

Rigid Designation and Modality

Questions have been raised about:

• whether all proper names are rigid in Kripke’s sense;
• how to treat indexicals, demonstratives, and definite descriptions used rigidly by stipulation;
• whether Kripke’s modal reasoning presupposes contentious metaphysical commitments about de re necessity and essentialism.

Some philosophers, influenced by Quine, remain skeptical of robust essentialist readings, while others develop systematic metaphysical frameworks inspired by Kripke.

Necessary A Posteriori and Contingent A Priori

Debate continues over:

• whether the necessary a posteriori is genuinely metaphysical necessity, or a product of semantics or conceptual frameworks;
• whether the contingent a priori cases are well‑described, or instead involve hidden empirical assumptions or misclassified stipulations.

Alternative accounts of the a priori and of analyticity have been proposed that reinterpret or reject Kripke’s taxonomy.

Natural Kinds and Mind–Body

Kripke’s views on natural kinds and essence have been challenged by philosophers who favor more pragmatic, anti‑essentialist, or socially constructed accounts of scientific categories. Others question whether scientific practice supports the idea of fixed microstructural essences.

In philosophy of mind, defenders of physicalism and the mind–brain identity theory contend that Kripke mischaracterizes the relevant necessities or that his argument depends on controversial assumptions about phenomenal concepts and conceivability.

These debates remain active, and many contemporary theories of reference, modality, natural kinds, and consciousness are formulated partly in response to Kripke’s framework.

16. Legacy and Historical Significance

Naming and Necessity is widely regarded as a landmark in late 20th‑century analytic philosophy, with enduring influence across several subfields.

Impact on Philosophy of Language and Metaphysics

The work significantly reshaped the theory of reference, dislodging pure descriptivism as the default view of proper names and stimulating a rich literature on causal, social, and hybrid accounts. The concepts of rigid designation and the necessary a posteriori became standard tools, informing debates about identity, modality, and essence.

In metaphysics, Kripke’s use of possible worlds and de re modality contributed to the revival of serious metaphysical inquiry within the analytic tradition. His discussion of essences for individuals and natural kinds influenced subsequent work on essentialism, counterpart theory, and the ontology of properties and kinds.

Broader Philosophical Influence

Kripke’s arguments about mind–brain identity helped formulate key challenges for physicalist theories of mind and played a role in later discussions of qualia, consciousness, and the explanatory gap. His natural‑kind semantics intersected with developments in philosophy of science and metaphysics of natural kinds, and his examples and methods have informed work in epistemology, logic, and the philosophy of logic.

Place in the History of Analytic Philosophy

Historically, Naming and Necessity is often seen as marking a transition from the dominance of logical empiricism and ordinary‑language philosophy toward a more metaphysically robust, yet still analytically oriented, style of philosophy. It stands alongside works by Putnam, Lewis, and others as part of a broader reconfiguration of analytic philosophy in the 1960s and 1970s.

The book continues to be a central text in graduate and advanced undergraduate curricula, and its terminology and examples have entered the common vocabulary of contemporary philosophy. Subsequent scholarship both builds upon and contests Kripke’s claims, but rarely ignores them, underscoring the work’s lasting historical significance.