Metaphysics

For other uses, see Metaphysics (disambiguation).

The beginning of Aristotle's Metaphysics, one of the foundational texts of the discipline

Metaphysics is the branch of philosophy that examines the basic structure of reality. It is traditionally seen as the study of mind-independent features of the world, but some modern theorists view it as an inquiry into the fundamental categories of human understanding. Some philosophers, including Aristotle, designate metaphysics as first philosophy to suggest that it is more fundamental than other forms of philosophical inquiry.

Metaphysics encompasses a wide range of general and abstract topics. It investigates the nature of existence, the features all entities have in common, and their division into categories of being. An influential division is between particulars and universals. Particulars are individual unique entities, like a specific apple. Universals are general features that different particulars have in common, like the color red. Modal metaphysics examines what it means for something to be possible or necessary. Metaphysicians also explore the concepts of space, time, and change, and their connection to causality and the laws of nature. Other topics include how mind and matter are related, whether everything in the world is predetermined, and whether there is free will.

Metaphysicians use various methods to conduct their inquiry. Traditionally, they rely on rational intuitions and abstract reasoning but have more recently also included empirical approaches associated with scientific theories. Due to the abstract nature of its topic, metaphysics has received criticisms questioning the reliability of its methods and the meaningfulness of its theories. Metaphysics is relevant to many fields of inquiry that often implicitly rely on metaphysical concepts and assumptions.

The roots of metaphysics lie in antiquity with speculations about the nature and origin of universe, like those found in the Upanishads in ancient India, Daoism in ancient China, and pre-Socratic philosophy in ancient Greece. During the subsequent medieval period in the West, discussions about the nature of universals were influenced by the philosophies of Plato and Aristotle. The modern period saw the emergence of various comprehensive systems of metaphysics, many of which embraced idealism. In the 20th century, traditional metaphysics in general and idealism in particular faced various criticisms, which prompted new approaches to metaphysical inquiry.

Definition

Metaphysics is the study of the most general features of reality, including existence, objects and their properties, possibility and necessity, space and time, change, causation, and the relation between matter and mind. It is one of the oldest branches of philosophy.

The precise nature of metaphysics is disputed and its characterization has changed in the course of history. Some approaches see metaphysics as a unified field and give a wide-sweeping definition by understanding it as the study of "fundamental questions about the nature of reality" or as an inquiry into the essences of things. Another approach doubts that the different areas of metaphysics share a set of underlying features and provides instead a fine-grained characterization by listing all the main topics investigated by metaphysicians. Some definitions are descriptive by providing an account of what metaphysicians do while others are normative and prescribe what metaphysicians ought to do.

Two historically influential definitions in ancient and medieval philosophy understand metaphysics as the science of the first causes and as the study of being qua being, that is, the topic of what all beings have in common and to what fundamental categories they belong. In the modern period, the scope of metaphysics expanded to include topics such as the distinction between mind and body and free will. Some philosophers follow Aristotle in describing metaphysics as "first philosophy", suggesting that it is the most basic inquiry upon which all other branches of philosophy depend in some way.

Immanuel Kant conceived critical metaphysics as the study of the principles underlying all human thought and experience.

Metaphysics is traditionally understood as a study of mind-independent features of reality. Starting with Immanuel Kant's critical philosophy, an alternative conception gained prominence that focuses on conceptual schemes rather than external reality. Kant distinguishes transcendent metaphysics, which aims to describe the objective features of reality beyond sense experience, from critical metaphysics, which outlines the aspects and principles underlying all human thought and experience. Philosopher P. F. Strawson further explored the role of conceptual schemes, contrasting descriptive metaphysics, which articulates conceptual schemes commonly used to understand the world, with revisionary metaphysics, which aims to produce better conceptual schemes.

Metaphysics differs from the individual sciences by studying the most general and abstract aspects of reality. The individual sciences, by contrast, examine more specific and concrete features and restrict themselves to certain classes of entities, such as the focus on physical things in physics, living entities in biology, and cultures in anthropology. It is disputed to what extent this contrast is a strict dichotomy rather than a gradual continuum.

Etymology

The word metaphysics has its origin in the ancient Greek words metá (μετά, meaning 'after', 'above', and 'beyond'') and phusiká (φυσικά), as a short form of ta metá ta phusiká, meaning 'what comes after the physics'. This is often interpreted to mean that metaphysics discusses topics that, due to their generality and comprehensiveness, lie beyond the realm of physics and its focus on empirical observation. Metaphysics got its name by a historical accident when Aristotle's book on this subject was published. Aristotle did not use the term metaphysics but his editor (likely Andronicus of Rhodes) may have coined it for its title to indicate that this book should be studied after Aristotle's book published on physics: literally after physics. The term entered the English language through the Latin word metaphysica.

Branches

The nature of metaphysics can also be characterized in relation to its main branches. An influential division from early modern philosophy distinguishes between general and special or specific metaphysics. General metaphysics, also called ontology, takes the widest perspective and studies the most fundamental aspects of being. It investigates the features that all entities share and how entities can be divided into different categories. Categories are the most general kinds, such as substance, property, relation, and fact. Ontologists research which categories there are, how they depend on one another, and how they form a system of categories that provides a comprehensive classification of all entities.

Special metaphysics considers being from more narrow perspectives and is divided into subdisciplines based on the perspective they take. Metaphysical cosmology examines changeable things and investigates how they are connected to form a world as a totality extending through space and time. Rational psychology focuses on metaphysical foundations and problems concerning the mind, such as its relation to matter and the freedom of the will. Natural theology studies the divine and its role as the first cause. The scope of special metaphysics overlaps with other philosophical disciplines, making it unclear whether a topic belongs to it or to areas like philosophy of mind and theology.

Applied metaphysics is a relatively young subdiscipline. It belongs to applied philosophy and studies the applications of metaphysics, both within philosophy and other fields of inquiry. In areas like ethics and philosophy of religion, it addresses topics like the ontological foundations of moral claims and religious doctrines. Beyond philosophy, its applications include the use of ontologies in artificial intelligence, economics, and sociology to classify entities. In psychiatry and medicine, it examines the metaphysical status of diseases.

Meta-metaphysics is the metatheory of metaphysics and investigates the nature and methods of metaphysics. It examines how metaphysics differs from other philosophical and scientific disciplines and assesses its relevance to them. Even though discussions of these topics have a long history in metaphysics, meta-metaphysics has only recently developed into a systematic field of inquiry.

Topics

Existence and categories of being

Main articles: Existence and Theory of categories

Metaphysicians often regard existence or being as one of the most basic and general concepts. To exist means to form part of reality, distinguishing real entities from imaginary ones. According to the orthodox view, existence is a property of properties: if an entity exists then its properties are instantiated. A different position states that existence is a property of individuals, meaning that it is similar to other properties, such as shape or size. It is controversial whether all entities have this property. According to Alexius Meinong, there are nonexistent objects, including merely possible objects like Santa Claus and Pegasus. A related question is whether existence is the same for all entities or whether there are different modes or degrees of existence. For instance, Plato held that Platonic forms, which are perfect and immutable ideas, have a higher degree of existence than matter, which can only imperfectly reflect Platonic forms.

Another key concern in metaphysics is the division of entities into distinct groups based on underlying features they share. Theories of categories provide a system of the most fundamental kinds or the highest genera of being by establishing a comprehensive inventory of everything. One of the earliest theories of categories was proposed by Aristotle, who outlined a system of 10 categories. He argued that substances (e.g. man and horse), are the most important category since all other categories like quantity (e.g. four), quality (e.g. white), and place (e.g. in Athens) are said of substances and depend on them. Kant understood categories as fundamental principles underlying human understanding and developed a system of 12 categories, divided into the four classes quantity, quality, relation, and modality. More recent theories of categories were proposed by C. S. Peirce, Edmund Husserl, Samuel Alexander, Roderick Chisholm, and E. J. Lowe. Many philosophers rely on the contrast between concrete and abstract objects. According to a common view, concrete objects, like rocks, trees, and human beings, exist in space and time, undergo changes, and impact each other as cause and effect. They contrast with abstract objects, like numbers and sets, which do not exist in space and time, are immutable, and do not engage in causal relations.

Particulars

Particulars are individual entities and include both concrete objects, like Aristotle, the Eiffel Tower, or a specific apple, and abstract objects, like the number 2 or a specific set in mathematics. Also called individuals, they are unique, non-repeatable entities and contrast with universals, like the color red, which can at the same time exist in several places and characterize several particulars. A widely held view is that particulars instantiate universals but are not themselves instantiated by something else, meaning that they exist in themselves while universals exist in something else. Substratum theory analyzes each particular as a substratum, also called bare particular, together with various properties. The substratum confers individuality to the particular while the properties express its qualitative features or what it is like. This approach is rejected by bundle theorists, who state that particulars are only bundles of properties without an underlying substratum. Some bundle theorists include in the bundle an individual essence, called haecceity, to ensure that each bundle is unique. Another proposal for concrete particulars is that they are individuated by their space-time location.

Concrete particulars encountered in everyday life, like rocks, tables, and organisms, are complex entities composed of various parts. For example, a table is made up of a tabletop and legs, each of which is itself made up of countless particles. The relation between parts and wholes is studied by mereology. The problem of the many is about which groups of entities form mereological wholes, for instance, whether a dust particle on the tabletop is part of the table. According to mereological universalists, every collection of entities forms a whole, meaning that the parts of the table without the dust particle form one whole while they together with it form a second whole. Mereological moderatists hold that certain conditions must be met for a group of entities to compose a whole, for example, that the entities touch one another. Mereological nihilists reject the idea of wholes altogether, claiming that there are no tables and chairs but only particles that are arranged table-wise and chair-wise. A related mereological problem is whether there are simple entities that have no parts, as atomists claim, or not, as continuum theorists contend.

Universals

Main article: Universal (metaphysics)

Universals are general entities, encompassing both properties and relations, that express what particulars are like and how they resemble one another. They are repeatable, meaning that they are not limited to a unique existent but can be instantiated by different particulars at the same time. For example, the particulars Nelson Mandela and Mahatma Gandhi instantiate the universal humanity, similar to how a strawberry and a ruby instantiate the universal red.

A topic discussed since ancient philosophy, the problem of universals consists in the challenge of characterizing the ontological status of universals. Realists argue that universals are real, mind-independent entities that exist in addition to particulars. According to Platonic realists, universals exist independently of particulars, which implies that the universal red would continue to exist even if there were no red things. A more moderate form of realism, inspired by Aristotle, states that universals depend on particulars, meaning that they are only real if they are instantiated. Nominalists reject the idea that universals exist in either form. For them, the world is composed exclusively of particulars. Conceptualists offer an intermediate position, stating that universals exist, but only as concepts in the mind used to order experience by classifying entities.

Natural and social kinds are often understood as special types of universals. Entities belonging to the same natural kind share certain fundamental features characteristic of the structure of the natural world. In this regard, natural kinds are not an artificially constructed classification but are discovered, usually by the natural sciences, and include kinds like electrons, H₂O, and tigers. Scientific realists and anti-realists disagree about whether natural kinds exist. Social kinds, like money and baseball, are studied by social metaphysics and characterized as useful social constructions that, while not purely fictional, do not reflect the fundamental structure of mind-independent reality.

Possibility and necessity

The concepts of possibility and necessity convey what can or must be the case, expressed in statements like "it is possible to find a cure for cancer" and "it is necessary that two plus two equals four". They belong to modal metaphysics, which investigates the metaphysical principles underlying them, in particular, why some modal statements are true while others are false. Some metaphysicians hold that modality is a fundamental aspect of reality, meaning that besides facts about what is the case, there are additional facts about what could or must be the case. A different view argues that modal truths are not about an independent aspect of reality but can be reduced to non-modal characteristics, for example, to facts about what properties or linguistic descriptions are compatible with each other or to fictional statements.

Borrowing a term from German philosopher Gottfried Wilhelm Leibniz's theodicy, many metaphysicians use the concept of possible worlds to analyze the meaning and ontological ramifications of modal statements. A possible world is a complete and consistent way of how things could have been. For example, the dinosaurs were wiped out in the actual world but there are possible worlds in which they are still alive. According to possible world semantics, a statement is possibly true if it is true in at least one possible world, whereas it is necessarily true if it is true in all possible worlds. Modal realists argue that possible worlds exist as concrete entities in the same sense as the actual world, with the main difference being that the actual world is the world we live in while other possible worlds are inhabited by counterparts. This view is controversial and various alternatives have been suggested, for example, that possible worlds only exist as abstract objects or are similar to stories told in works of fiction.

Space, time, and change

Main article: Philosophy of space and time

Space and time are dimensions that entities occupy. Spacetime realists state that space and time are fundamental aspects of reality and exist independently of the human mind. Spacetime idealists, by contrast, hold that space and time are constructs of the human mind, created to organize and make sense of reality. Spacetime absolutism or substantivalism understands spacetime as a distinct object, with some metaphysicians conceptualizing it as a container that holds all other entities within it. Spacetime relationism sees spacetime not as an object but as a network of relations between objects, such as the spatial relation of being next to and the temporal relation of coming before.

In the metaphysics of time, an important contrast is between the A-series and the B-series. According to the A-series theory, the flow of time is real, meaning that events are categorized into the past, present, and future. The present continually moves forward in time and events that are in the present now will eventually change their status and lie in the past. From the perspective of the B-series theory, time is static, and events are ordered by the temporal relations earlier-than and later-than without any essential difference between past, present, and future. Eternalism holds that past, present, and future are equally real, whereas presentism asserts that only entities in the present exist.

Material objects persist through time and change in the process, like a tree that grows or loses leaves. The main ways of conceptualizing persistence through time are endurantism and perdurantism. According to endurantism, material objects are three-dimensional entities that are wholly present at each moment. As they change, they gain or lose properties but otherwise remain the same. Perdurantists see material objects as four-dimensional entities that extend through time and are made up of different temporal parts. At each moment, only one part of the object is present, not the object as a whole. Change means that an earlier part is qualitatively different from a later part. For example, when a banana ripens, there is an unripe part followed by a ripe part.

Causality

Main article: Causality

Causality is the relation between cause and effect whereby one entity produces or affects another entity. For instance, if a person bumps a glass and spills its contents then the bump is the cause and the spill is the effect. Besides the single-case causation between particulars in this example, there is also general-case causation expressed in statements such as "smoking causes cancer". The term agent causation is used when people and their actions cause something. Causation is usually interpreted deterministically, meaning that a cause always brings about its effect. This view is rejected by probabilistic theories, which claim that the cause merely increases the probability that the effect occurs. This view can explain that smoking causes cancer even though this does not happen in every single case.

The regularity theory of causation, inspired by David Hume's philosophy, states that causation is nothing but a constant conjunction in which the mind apprehends that one phenomenon, like putting one's hand in a fire, is always followed by another phenomenon, like a feeling of pain. According to nomic regularity theories, regularities manifest as laws of nature studied by science. Counterfactual theories focus not on regularities but on how effects depend on their causes. They state that effects owe their existence to the cause and would not occur without them. According to primitivism, causation is a basic concept that cannot be analyzed in terms of non-causal concepts, such as regularities or dependence relations. One form of primitivism identifies causal powers inherent in entities as the underlying mechanism. Eliminativists reject the above theories by holding that there is no causation.

Mind and free will

Main articles: Mind and Free will

Different approaches toward resolving the mind–body problem

Mind encompasses phenomena like thinking, perceiving, feeling, and desiring as well as the underlying faculties responsible for these phenomena. The mind–body problem is the challenge of clarifying the relation between physical and mental phenomena. According to Cartesian dualism, minds and bodies are distinct substances. They causally interact with each other in various ways but can, at least in principle, exist on their own. This view is rejected by monists, who argue that reality is made up of only one kind. According to idealism, everything is mental, including physical objects, which may be understood as ideas or perceptions of conscious minds. Materialists, by contrast, state that all reality is at its core material. Some deny that mind exists but the more common approach is to explain mind in terms of certain aspects of matter, such as brain states, behavioral dispositions, or functional roles. Neutral monists argue that reality is fundamentally neither material nor mental and suggest that matter and mind are both derivative phenomena. A key aspect of the mind–body problem is the hard problem of consciousness or how to explain that physical systems like brains can produce phenomenal consciousness.

The status of free will as the ability of a person to choose their actions is a central aspect of the mind–body problem. Metaphysicians are interested in the relation between free will and causal determinism—the view that everything in the universe, including human behavior, is determined by preceding events and laws of nature. It is controversial whether causal determinism is true, and, if so, whether this would imply that there is no free will. According to incompatibilism, free will cannot exist in a deterministic world since there is no true choice or control if everything is determined. Hard determinists infer from this that there is no free will, whereas libertarians conclude that determinism must be false. Compatibilists offer a third perspective, arguing that determinism and free will do not exclude each other, for instance, because a person can still act in tune with their motivation and choices even if they are determined by other forces. Free will plays a key role in ethics regarding the moral responsibility people have for what they do.

Others

Identity is a relation that every entity has to itself as a form of sameness. It refers to numerical identity when the very same entity is involved, as in the statement "the morning star is the evening star" (both are the planet Venus). In a slightly different sense, it encompasses qualitative identity, also called exact similarity and indiscernibility, which occurs when two distinct entities are exactly alike, such as perfect identical twins. The principle of the indiscernibility of identicals is widely accepted and holds that numerically identical entities exactly resemble one another. The converse principle, known as identity of indiscernibles or Leibniz's Law, is more controversial and states that two entities are numerically identical if they exactly resemble one another. Another distinction is between synchronic and diachronic identity. Synchronic identity relates an entity to itself at the same time, whereas diachronic identity is about the same entity at different times, as in statements like "the table I bought last year is the same as the table in my dining room now". Personal identity is a related topic in metaphysics that uses the term identity in a slightly different sense and concerns questions like what personhood is or what makes someone a person.

Various contemporary metaphysicians rely on the concepts of truth, truth-bearer, and truthmaker to conduct their inquiry. Truth is a property of being in accord with reality. Truth-bearers are entities that can be true or false, such as linguistic statements and mental representations. A truthmaker of a statement is the entity whose existence makes the statement true. For example, the statement "a tomato is red" is true because there exists a red tomato as its truthmaker. Based on this observation, it is possible to pursue metaphysical research by asking what the truthmakers of statements are, with different areas of metaphysics being dedicated to different types of statements. According to this view, modal metaphysics asks what makes statements about what is possible and necessary true while the metaphysics of time is interested in the truthmakers of temporal statements about the past, present, and future.

Methodology

Metaphysicians employ a variety of methods to develop metaphysical theories and formulate arguments for and against them. Traditionally, a priori methods have been the dominant approach. They rely on rational intuition and abstract reasoning from general principles rather than sensory experience. A posteriori approaches, by contrast, ground metaphysical theories in empirical observations and scientific theories. Some metaphysicians incorporate perspectives from fields such as physics, psychology, linguistics, and history into their inquiry. The two approaches are not mutually exclusive: it is possible to combine elements from both. The method a metaphysician chooses often depends on their understanding of the nature of metaphysics, for example, whether they see it as an inquiry into the mind-independent structure of reality, as metaphysical realists claim, or the principles underlying thought and experience, as some metaphysical anti-realists contend.

A priori approaches often rely on intuitions—non-inferential impressions about the correctness of specific claims or general principles. For example, arguments for the A-theory of time, which states that time flows from the past through the present and into the future, often rely on pre-theoretical intuitions associated with the sense of the passage of time. Some approaches use intuitions to establish a small set of self-evident fundamental principles, known as axioms, and employ deductive reasoning to build complex metaphysical systems by drawing conclusions from these axioms. Intuition-based approaches can be combined with thought experiments, which help evoke and clarify intuitions by linking them to imagined situations. They use counterfactual thinking to assess the possible consequences of these situations. For example, to explore the relation between matter and consciousness, some theorists compare humans to philosophical zombies—hypothetical creatures identical to humans but without conscious experience. A related method relies on commonly accepted beliefs instead of intuitions to formulate arguments and theories. The common-sense approach is often used to criticize metaphysical theories that deviate significantly from how the average person thinks about an issue. For example, common-sense philosophers have argued that mereological nihilism is false since it implies that commonly accepted things, like tables, do not exist.

Conceptual analysis, a method particularly prominent in analytic philosophy, aims to decompose metaphysical concepts into component parts to clarify their meaning and identify essential relations. In phenomenology, the method of eidetic variation is used to investigate essential structures underlying phenomena. This method involves imagining an object and varying its features to determine which ones are essential and cannot be changed. The transcendental method is a further approach and examines the metaphysical structure of reality by observing what entities there are and studying the conditions of possibility without which these entities could not exist.

Some approaches give less importance to a priori reasoning and view metaphysics as a practice continuous with the empirical sciences that generalizes their insights while making their underlying assumptions explicit. This approach is known as naturalized metaphysics and is closely associated with the work of Willard Van Orman Quine. He relies on the idea that true sentences from the sciences and other fields have ontological commitments, that is, they imply that certain entities exist. For example, if the sentence "some electrons are bonded to protons" is true then it can be used to justify that electrons and protons exist. Quine used this insight to argue that one can learn about metaphysics by closely analyzing scientific claims to understand what kind of metaphysical picture of the world they presuppose.

In addition to methods of conducting metaphysical inquiry, there are various methodological principles used to decide between competing theories by comparing their theoretical virtues. Ockham's Razor is a well-known principle that gives preference to simple theories, in particular, those that assume that few entities exist. Other principles consider explanatory power, theoretical usefulness, and proximity to established beliefs.

Criticism

David Hume criticized metaphysicians for trying to gain knowledge outside the field of sensory experience.

Despite its status as one of the main branches of philosophy, metaphysics has received numerous criticisms questioning its legitimacy as a field of inquiry. One criticism argues that metaphysical inquiry is impossible because humans lack the cognitive capacities needed to access the ultimate nature of reality. This line of thought leads to skepticism about the possibility of metaphysical knowledge. Empiricists often follow this idea, like Hume, who argued that there is no good source of metaphysical knowledge since metaphysics lies outside the field of empirical knowledge and relies on dubious intuitions about the realm beyond sensory experience. A related argument favoring the unreliability of metaphysical theorizing points to the deep and lasting disagreements about metaphysical issues, suggesting a lack of overall progress.

Another criticism holds that the problem lies not with human cognitive abilities but with metaphysical statements themselves, which some claim are neither true nor false but meaningless. According to logical positivists, for instance, the meaning of a statement is given by the procedure used to verify it, usually through the observations that would confirm it. Based on this controversial assumption, they argue that metaphysical statements are meaningless since they make no testable predictions about experience.

A slightly weaker position allows metaphysical statements to have meaning while holding that metaphysical disagreements are merely verbal disputes about different ways to describe the world. According to this view, the disagreement in the metaphysics of composition about whether there are tables or only particles arranged table-wise is a trivial debate about linguistic preferences without any substantive consequences for the nature of reality. The position that metaphysical disputes have no meaning or no significant point is called metaphysical or ontological deflationism. This view is opposed by so-called serious metaphysicians, who contend that metaphysical disputes are about substantial features of the underlying structure of reality. A closely related debate between ontological realists and anti-realists concerns the question of whether there are any objective facts that determine which metaphysical theories are true. A different criticism, formulated by pragmatists, sees the fault of metaphysics not in its cognitive ambitions or the meaninglessness of its statements, but in its practical irrelevance and lack of usefulness.

Martin Heidegger criticized traditional metaphysics, saying that it fails to distinguish between individual entities and being as their ontological ground. His attempt to reveal the underlying assumptions and limitations in the history of metaphysics to "overcome metaphysics" influenced Jacques Derrida's method of deconstruction. Derrida employed this approach to criticize metaphysical texts for relying on opposing terms, like presence and absence, which he thought were inherently unstable and contradictory.

There is no consensus about the validity of these criticisms and whether they affect metaphysics as a whole or only certain issues or approaches in it. For example, it could be the case that certain metaphysical disputes are merely verbal while others are substantive.

Relation to other disciplines

Metaphysics is related to many fields of inquiry by investigating their basic concepts and relation to the fundamental structure of reality. For example, the natural sciences rely on concepts such as law of nature, causation, necessity, and spacetime to formulate their theories and predict or explain the outcomes of experiments. While scientists primarily focus on applying these concepts to specific situations, metaphysics examines their general nature and how they depend on each other. For instance, physicists formulate laws of nature, like laws of gravitation and thermodynamics, to describe how physical systems behave under various conditions. Metaphysicians, by contrast, examine what all laws of nature have in common, asking whether they merely describe contingent regularities or express necessary relations. New scientific discoveries have also influenced existing and inspired new metaphysical theories. Einstein's theory of relativity, for instance, prompted various metaphysicians to conceive space and time as a unified dimension rather than as independent dimensions. Empirically focused metaphysicians often rely on scientific theories to ground their theories about the nature of reality in empirical observations.

Similar issues arise in the social sciences where metaphysicians investigate their basic concepts and analyze their metaphysical implications. This includes questions like whether social facts emerge from non-social facts, whether social groups and institutions have mind-independent existence, and how they persist through time. Metaphysical assumptions and topics in psychology and psychiatry include the questions about the relation between body and mind, whether the nature of the human mind is historically fixed, and what the metaphysical status of diseases is.

Metaphysics is similar to both physical cosmology and theology in its exploration of the first causes and the universe as a whole. Key differences are that metaphysics relies on rational inquiry while physical cosmology gives more weight to empirical observations and theology incorporates divine revelation and other faith-based doctrines. Historically, cosmology and theology were considered subfields of metaphysics.

Suggested Upper Merged Ontology

Entity       Physical       Object     Process     Abstract       Quantity     Proposition     Attribute     Relation     Set or Class

Fundamental categories in the Suggested Upper Merged Ontology

Metaphysics in the form of ontology plays a central role in computer science to classify objects and formally represent information about them. Unlike metaphysicians, computer scientists are usually not interested in providing a single all-encompassing characterization of reality as a whole. Instead, they employ many different ontologies, each one concerned only with a limited domain of entities. For instance, an organization may use an ontology with categories such as person, company, address, and name to represent information about clients and employees. Ontologies provide standards or conceptualizations for encoding and storing information in a structured way, enabling computational processes to use and transform their information for a variety of purposes. Some knowledge bases integrate information from various domains, which brings with it the challenge of handling data that was formulated using diverse ontologies. They address this by providing an upper ontology that defines concepts at a higher level of abstraction, applicable to all domains. Influential upper ontologies include Suggested Upper Merged Ontology and Basic Formal Ontology.

Logic as the study of correct reasoning is often used by metaphysicians as a tool to engage in their inquiry and express insights through precise logical formulas. Another relation between the two fields concerns the metaphysical assumptions associated with logical systems. Many logical systems like first-order logic rely on existential quantifiers to express existential statements. For instance, in the logical formula $\exists x{\text{Horse}}(x)$ the existential quantifier $\exists$ is applied to the predicate ${\text{Horse}}$ to express that there are horses. Following Quine, various metaphysicians assume that existential quantifiers carry ontological commitments, meaning that existential statements imply that the entities over which one quantifies are part of reality.

History

Main article: History of metaphysics

The taijitu symbol shows yin and yang, which are two correlated forces discussed in Chinese metaphysics to explore the nature and patterns of existence.

The history of metaphysics examines how the inquiry into the basic structure of reality has evolved in the course of history. Metaphysics originated in the ancient period from speculations about the nature and origin of the cosmos. In ancient India, starting in the 7th century BCE, the Upanishads were written as religious and philosophical texts that examine how ultimate reality constitutes the ground of all being. They further explore the nature of the self and how it can reach liberation by understanding ultimate reality. This period also saw the emergence of Buddhism in the 6th century BCE, which denies the existence of an independent self and understands the world as a cyclic process. At about the same time in ancient China, the school of Daoism was formed and explored the natural order of the universe, known as Dao, and how it is characterized by the interplay of yin and yang as two correlated forces.

In ancient Greece, metaphysics emerged in the 6th century BCE with the pre-Socratic philosophers, who gave rational explanations of the cosmos as a whole by examining the first principles from which everything arises. Building on their work, Plato (427–347 BCE) formulated his theory of forms, which states that eternal forms or ideas possess the highest kind of reality while the material world is only an imperfect reflection of them. Aristotle (384–322 BCE) accepted Plato's idea that there are universal forms but held that they cannot exist on their own but depend on matter. He also proposed a system of categories and developed a comprehensive framework of the natural world through his theory of the four causes. Starting in the 4th century BCE, Hellenistic philosophy explored the rational order underlying the cosmos and the idea that it is made up of indivisible atoms. Neoplatonism emerged towards the end of the ancient period in the 3rd century CE and introduced the idea of "the One" as the transcendent and ineffable source of all creation.

Meanwhile, in Indian Buddhism, the Madhyamaka school developed the idea that all phenomena are inherently empty without a permanent essence. The consciousness-only doctrine of the Yogācāra school stated that experienced objects are mere transformations of consciousness and do not reflect external reality. The Hindu school of Samkhya philosophy introduced a metaphysical dualism with pure consciousness and matter as its fundamental categories. In China, the school of Xuanxue explored metaphysical problems such as the contrast between being and non-being.

Boethius's theory of universals influenced many subsequent metaphysicians.

Medieval Western philosophy was profoundly shaped by ancient Greek philosophy. Boethius (477–524 CE) sought to reconcile Plato's and Aristotle's theories of universals, proposing that universals can exist both in matter and mind. His theory inspired the development of nominalism and conceptualism, as in the thought of Peter Abelard (1079–1142 CE). Thomas Aquinas (1224–1274 CE) understood metaphysics as the discipline investigating different meanings of being, such as the contrast between substance and accident, and principles applying to all beings, such as the principle of identity. William of Ockham (1285–1347 CE) proposed Ockham's razor, a methodological principles to choose between competing metaphysical theories. Arabic–Persian philosophy flourished from the early 9th century CE to the late 12th century CE, integrating ancient Greek philosophies to interpret and clarify the teachings of the Quran. Avicenna (980–1037 CE) developed a comprehensive philosophical system that examined the contrast between existence and essence and distinguished between contingent and necessary existence. Medieval India saw the emergence of the monist school of Advaita Vedanta in the 8th century CE, which holds that everything is one and that the idea of many entities existing independently is an illusion. In China, Neo-Confucianism arose in the 9th century CE and explored the concept of li as the rational principle that is the ground of being and reflects the order of the universe.

In the early modern period, René Descartes (1596–1650) developed a substance dualism according to which body and mind exist as independent entities that causally interact. This idea was rejected by Baruch Spinoza (1632–1677), who formulated a monist philosophy suggesting that there is only one substance with both physical and mental attributes that develop side-by-side without interacting. Gottfried Wilhelm Leibniz (1646–1716) introduced the concept of possible worlds and articulated a metaphysical system known as monadology, which views the universe as a collection of simple substances synchronized without causal interaction. Christian Wolff (1679–1754), conceptualized the scope of metaphysics by distinguishing between general and special metaphysics. According to the idealism of George Berkeley (1685–1753), everything is mental, including material objects, which are ideas perceived by the mind. David Hume (1711–1776) made various contributions to metaphysics, including the regularity theory of causation and the idea that there are no necessary connections between distinct entities. His empiricist outlook led him to criticize metaphysical theories that seek ultimate principles inaccessible to sensory experience. This skeptical outlook was embraced by Immanuel Kant (1724–1804), who tried to reconceptualize metaphysics as an inquiry into the basic principles and categories of thought and understanding rather than seeing it as an attempt to comprehend mind-independent reality.

Many developments in the later modern period were shaped by Kant's philosophy. German idealists adopted his idealistic outlook in their attempt to find a unifying principle as the foundation of all reality. Georg Wilhelm Friedrich Hegel (1770–1831) developed a comprehensive system of philosophy that examines how absolute spirit manifests itself. He inspired the British idealism of Francis Herbert Bradley (1846–1924), who interpreted absolute spirit as the all-inclusive totality of being. Arthur Schopenhauer (1788–1860) was a strong critic of German idealism and articulated a different metaphysical vision, positing a blind and irrational will as the underlying principle of reality. Pragmatists like C. S. Peirce (1839–1914) and John Dewey (1859–1952) conceived metaphysics as an observational science of the most general features of reality and experience.

Alfred North Whitehead articulated the foundations of process philosophy in his work Process and Reality.

At the turn of the 20th century in analytic philosophy, philosophers such as Bertrand Russell (1872–1970) and G. E. Moore (1873–1958) led a "revolt against idealism". Logical atomists, like Russell and the early Ludwig Wittgenstein (1889–1951), conceived the world as a multitude of atomic facts, which later inspired metaphysicians such as D. M. Armstrong (1926–2014). Alfred North Whitehead (1861–1947) developed process metaphysics as an attempt to provide a holistic description of both the objective and the subjective realms.

Rudolf Carnap (1891–1970) and other logical positivists formulated a wide-ranging criticism of metaphysical statements, arguing that they are meaningless because there is no way to verify them. Other criticisms of traditional metaphysics identified misunderstandings of ordinary language as the source of many traditional metaphysical problems or challenged complex metaphysical deductions by appealing to common sense.

The decline of logical positivism led to a revival of metaphysical theorizing. Willard Van Orman Quine (1908–2000) tried to naturalize metaphysics by connecting it to the empirical sciences. His student David Lewis (1941–2001) employed the concept of possible worlds to formulate his modal realism. Saul Kripke (1940–2022) helped revive discussions of identity and essentialism, distinguishing necessity as a metaphysical notion from the epistemic notion of a priori.

In continental philosophy, Edmund Husserl (1859–1938) engaged in ontology through a phenomenological description of experience, while his student Martin Heidegger (1889–1976) developed fundamental ontology to clarify the meaning of being. Heidegger's philosophy inspired general criticisms of metaphysics by postmodern thinkers like Jacques Derrida (1930–2004). Gilles Deleuze's (1925–1995) approach to metaphysics challenged traditionally influential concepts like substance, essence, and identity by reconceptualizing the field through alternative notions such as multiplicity, event, and difference.

See also

• Computational metaphysics
• Doctor of Metaphysics
• Enrico Berti's classification of metaphysics
• Feminist metaphysics
• Fundamental question of metaphysics
• List of metaphysicians
• Metaphysical grounding

References

Sources

• Adamson, Peter; Taylor, Richard C. (2004). The Cambridge Companion to Arabic Philosophy. Cambridge University Press. ISBN 978-1-107-49469-5. Retrieved 7 June 2023.
• AHD staff (2022). "The American Heritage Dictionary Entry: Existence". American Heritage Dictionary. HarperCollins. Archived from the original on 11 August 2023. Retrieved 10 August 2023.
• Ahmed, Arif (2010). Saul Kripke. Bloomsbury. ISBN 978-1-4411-9399-5.
• Andrea, Alfred J.; Overfield, James H. (2015). The Human Record: Sources of Global History, Volume I: To 1500. Cengage Learning. ISBN 978-1-305-53746-0. Retrieved 4 April 2024.
• Armstrong, D. M. (2018). The Mind-body Problem: An Opinionated Introduction. Routledge. ISBN 978-0-429-96480-0. Retrieved 29 March 2024.
• Asay, Jamin (2020). A Theory of Truthmaking: Metaphysics, Ontology, and Reality. Cambridge University Press. ISBN 978-1-108-60404-8. Retrieved 29 March 2024.
• Ásta (2017). "Social Kinds". The Routledge Handbook of Collective Intentionality. Routledge. pp. 290–299. doi:10.4324/9781315768571-27. ISBN 978-1-315-76857-1. Archived from the original on 26 March 2024. Retrieved 29 March 2024.
• Audi, Robert (2006). "Philosophy". In Borchert, Donald M. (ed.). Encyclopedia of Philosophy. 7: Oakeshott – Presupposition (2. ed.). Thomson Gale, Macmillan Reference. ISBN 978-0-02-865787-5. Archived from the original on 14 February 2022. Retrieved 10 November 2023.
• Baldwin, Tom (2010). "George Edward Moore". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Retrieved 30 April 2024.
• Barua, Arati (2018). "Introducing Schopenhauer's Philosophy of the World, Self, and Morality in the Light of Vedantic and Non-Vedantic Wisdom". In Barua, Arati (ed.). Schopenhauer on Self, World and Morality: Vedantic and Non-Vedantic Perspectives. Springer Nature Singapore. ISBN 978-981-10-5954-4.
• Beaulieu, Alain; Kazarian, Edward; Sushytska, Julia (2014). "Introduction: Gilles Deleuze and Metaphysics". In Beaulieu, Alain; Kazarian, Edward; Sushytska, Julia (eds.). Gilles Deleuze and Metaphysics. Lexington Books. ISBN 978-0-7391-7476-0.
• Bengtson, Josef (2015). Explorations in Post-Secular Metaphysics. Springer. ISBN 978-1-137-55336-2. Retrieved 21 March 2024.
• Benovsky, Jiri (2016). Meta-metaphysics: On Metaphysical Equivalence, Primitiveness, and Theory Choice. Springer. ISBN 978-3-319-25334-3. Retrieved 29 March 2024.
• Berryman, Sylvia (2022). "Ancient Atomism". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 2 May 2019. Retrieved 25 March 2024.
• Berthrong, John H. "Neo-Confucian Philosophy". Internet Encyclopedia of Philosophy. Archived from the original on 6 February 2024. Retrieved 31 March 2024.
• Berto, Francesco; Jago, Mark (2023). "Impossible Worlds". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 10 February 2021. Retrieved 17 February 2024.
• Bigelow, John C. (1998). "Particulars". Routledge Encyclopedia of Philosophy. Routledge. doi:10.4324/9780415249126-N040-1. ISBN 978-0-415-25069-6. Archived from the original on 25 March 2024. Retrieved 24 March 2024.
• Bigelow, John C. (1998a). "Universals". Routledge Encyclopedia of Philosophy. Routledge. doi:10.4324/9780415249126-N065-1. ISBN 978-0-415-25069-6. Archived from the original on 25 March 2024. Retrieved 25 March 2024.
• Bird, Alexander; Tobin, Emma (2024). "Natural Kinds". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Retrieved 26 March 2024.
• Blackburn, Simon (2008). "Existence". The Oxford Dictionary of Philosophy. Oxford University Press. ISBN 978-0-19-954143-0. Archived from the original on 10 August 2023. Retrieved 1 September 2023.
• Blair, J. Anthony; Johnson, Ralph H. (2000). "Informal Logic: An Overview". Informal Logic. 20 (2). doi:10.22329/il.v20i2.2262. Archived from the original on 9 December 2021. Retrieved 29 December 2021.
• Brenner, Andrew (2015). "Mereological Nihilism and the Special Arrangement Question". Synthese. 192 (5): 1295–1314. doi:10.1007/s11229-014-0619-7.
• Broadbent, Alex (2016). Philosophy for Graduate Students: Metaphysics and Epistemology. Routledge. ISBN 978-1-317-39714-4.
• Brown, Christopher M. "Thomas Aquinas". Internet Encyclopedia of Philosophy. Archived from the original on 13 March 2024. Retrieved 31 March 2024.
• Brown, James Robert; Fehige, Yiftach (2019). "Thought Experiments". Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 21 November 2017. Retrieved 29 October 2021.
• Brumbaugh, Robert S. (1966). "Applied Metaphysics: Truth and Passing Time". The Review of Metaphysics. 19 (4): 647–666. ISSN 0034-6632. JSTOR 20124133. OCLC 9970206403. Archived from the original on 20 March 2024. Retrieved 21 March 2024.
• Brzović, Zdenka. "Natural Kinds". Internet Encyclopedia of Philosophy. Archived from the original on 13 March 2024. Retrieved 26 March 2024.
• Campbell, Keith (2006). "Ontology". In Borchert, Donald M. (ed.). Encyclopedia of Philosophy. 7: Oakeshott – Presupposition (2. ed.). Thomson Gale, Macmillan Reference. ISBN 978-0-02-865787-5. Archived from the original on 29 January 2021. Retrieved 21 March 2024.
• Carroll, John W.; Markosian, Ned (2010). An Introduction to Metaphysics (1 ed.). Cambridge University Press. ISBN 978-0-521-82629-7.
• Casati, Filippo; Fujikawa, Naoya. "Existence". Internet Encyclopedia of Philosophy. Archived from the original on 10 August 2023. Retrieved 7 August 2023.
• Chai, David (2020). Dao Companion to Xuanxue 玄學 (Neo-Daoism). Springer. ISBN 978-3-030-49228-1. Retrieved 4 April 2024.
• Chalmers, David J. (2009). "3. Ontological Anti-Realism". Metametaphysics: New Essays on the Foundations of Ontology. Clarendon Press. ISBN 978-0-19-954604-6.
• Chen, Binggong (2023). Principles of Subjective Anthropology: Concepts and the Knowledge System. Springer Nature Singapore. ISBN 978-981-19-8883-7.
• Coelho, Ivo (2001). Hermeneutics and Method: The 'Universal Viewpoint' in Bernard Lonergan. University of Toronto Press. ISBN 978-0-8020-4840-0. Retrieved 18 March 2024.
• Cohen, S. Marc; Reeve, C. D. C. (2021). "Aristotle's Metaphysics". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 11 May 2020. Retrieved 10 April 2024.
• Cook, Roy T. (2009). Dictionary of Philosophical Logic. Edinburgh University Press. ISBN 978-0-7486-3197-1. Retrieved 1 September 2023.
• Corkum, Philip (2015). "Generality and Logical Constancy". Revista Portuguesa de Filosofia. 71 (4): 753–768. doi:10.17990/rpf/2015_71_4_0753. ISSN 0870-5283. JSTOR 43744657.
• Cornell, David. "Material Composition". Internet Encyclopedia of Philosophy. Archived from the original on 25 March 2024. Retrieved 25 March 2024.
• Costa, Damiano. "Persistence in Time". Internet Encyclopedia of Philosophy. Archived from the original on 17 August 2021. Retrieved 26 March 2024.
• Cowling, Sam (2019). "Universals". Routledge Encyclopedia of Philosophy. Routledge. doi:10.4324/9780415249126-N065-2. ISBN 978-0-415-25069-6. Archived from the original on 29 March 2024. Retrieved 25 March 2024.
• Craig, Edward (1998). "Metaphysics". Routledge Encyclopedia of Philosophy. Routledge. ISBN 978-0-415-25069-6. Archived from the original on 1 August 2023. Retrieved 19 March 2024.
• Critchley, Simon (2001). Continental Philosophy: A Very Short Introduction. Oxford University Press. ISBN 978-0-19-157832-8. Retrieved 4 April 2024.
• Dafermos, Manolis (2021). "The Metaphysics of Psychology and a Dialectical Perspective". Theory & Psychology. 31 (3): 355–374. doi:10.1177/0959354320975491.
• Dainton, Barry (2010). "Spatial Anti-realism". Time and Space (2 ed.). Acumen Publishing. ISBN 978-1-84465-190-0. Archived from the original on 26 March 2024. Retrieved 29 March 2024.
• Dalal, Neil (2021). "Śaṅkara". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 27 January 2022. Retrieved 2 April 2024.
• Daly, Christopher (2015). "Introduction and Historical Overview". The Palgrave Handbook of Philosophical Methods. Palgrave Macmillan. pp. 1–30. doi:10.1057/9781137344557_1. ISBN 978-1-137-34455-7. Archived from the original on 1 May 2022. Retrieved 18 April 2022.
• Dehsen, Christian von (2013). Philosophers and Religious Leaders. Routledge. ISBN 978-1-135-95102-3. Retrieved 28 May 2023.
• Depraz, Nathalie; Varela, Francisco J.; Vermersch, Pierre (2003). On Becoming Aware: A Pragmatics of Experiencing. John Benjamins Publishing. ISBN 978-90-272-9683-2. Retrieved 4 April 2024.
• Desmet, Ronald; Irvine, Andrew David (2022). "Alfred North Whitehead". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Retrieved 1 April 2024.
• Dharamsi, Karim (2017). "Liberation from Solitude: Wittgenstein on Human Finitude and Possibility". In Peters, Michael A.; Stickney, Jeff (eds.). A Companion to Wittgenstein on Education: Pedagogical Investigations. Springer Nature Singapore. ISBN 978-981-10-3136-6.
• Drummond, John J. (2022). Historical Dictionary of Husserl's Philosophy. Rowman & Littlefield. ISBN 978-1-5381-3345-3. Retrieved 18 March 2024.
• Dryer, D. P. (2016). Kant's Solution for Verification in Metaphysics. Routledge. ISBN 978-1-315-53632-3. Retrieved 9 April 2024.
• Duignan, Brian (2009a). "Intuitionism (Ethics)". Encyclopædia Britannica. Archived from the original on 7 March 2022. Retrieved 28 February 2022.
• Dyke, Heather (2002). "McTaggart and the Truth About Time". In Callender, Craig (ed.). Time, Reality and Experience. Cambridge University Press. ISBN 978-0-521-52967-9. Retrieved 29 March 2024.
• Dynes, Wayne R. (2016). "Creation of Daoism (6th Century BC)". In Curta, Florin; Holt, Andrew (eds.). Great Events in Religion: An Encyclopedia of Pivotal Events in Religious History. Bloomsbury. ISBN 978-1-61069-566-4. Retrieved 4 April 2024.
• Eder, Anna-Maria A.; Lawler, Insa; Van Riel, Raphael (2020). "Philosophical Methods Under Scrutiny: Introduction to the Special Issue Philosophical Methods". Synthese. 197 (3): 915–923. doi:10.1007/s11229-018-02051-2. ISSN 1573-0964. S2CID 54631297.
• Effingham, Nikk; Beebee, Helen; Goff, Philip (2010). Metaphysics: The Key Concepts. Routledge. ISBN 978-1-136-85518-4. Retrieved 18 March 2024.
• Erasmus, Jacobus (2018). The Kalām Cosmological Argument: A Reassessment. Springer. ISBN 978-3-319-73438-5. Retrieved 29 March 2024.
• Falguera, José L.; Martínez-Vidal, Concha; Rosen, Gideon (2022). "Abstract Objects". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 22 January 2021. Retrieved 22 March 2024.
• Gallois, Andre (2016). "Identity Over Time". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Retrieved 28 March 2024.
• George, Siby K. (2015). Heidegger and Development in the Global South. Springer India. ISBN 978-81-322-2304-7.
• Gilje, Nils; Skirbekk, Gunnar (2017). A History of Western Thought: From Ancient Greece to the Twentieth Century. Routledge. ISBN 978-1-135-22604-6. Retrieved 4 April 2024.
• Goffi, Jean-Yves; Roux, Sophie (2011). "On the Very Idea of a Thought Experiment". Thought Experiments in Methodological and Historical Contexts. Brill: 165–191. doi:10.1163/ej.9789004201767.i-233.35. ISBN 978-90-04-20177-4. S2CID 260640180. Archived from the original on 30 October 2021. Retrieved 18 April 2022.
• Göhner, Julia F.; Schrenk, Markus. "Metaphysics of Science". Internet Encyclopedia of Philosophy. Archived from the original on 7 April 2024. Retrieved 7 April 2024.
• Goldenbaum, Ursula. "Geometrical Method". Internet Encyclopedia of Philosophy. Archived from the original on 7 March 2022. Retrieved 15 March 2024.
• Goswick, Dana (2018). "6. Are Modal Facts Brute Facts?". In Vintiadis, Elly; Mekios, Constantinos (eds.). Brute Facts. Oxford University Press. ISBN 978-0-19-875860-0. Archived from the original on 22 March 2024. Retrieved 29 March 2024.
• Graham, Jacob N. "Ancient Greek Philosophy". Internet Encyclopedia of Philosophy. Archived from the original on 25 August 2022. Retrieved 2 April 2024.
• Grayling, A. C. (2019). The History of Philosophy. Penguin UK. ISBN 978-0-241-98086-6. Retrieved 30 June 2023.
• Green, Garrett (2008). "Modernity". In Jones, Gareth (ed.). The Blackwell Companion to Modern Theology. John Wiley & Sons. ISBN 978-0-470-99733-8. Retrieved 4 April 2024.
• Griffin, Nicholas (1998). "Neutral Monism". Routledge Encyclopedia of Philosophy. Routledge. doi:10.4324/9780415249126-N035-1. ISBN 978-0-415-25069-6. Archived from the original on 27 March 2024. Retrieved 27 March 2024.
• Griffin, Nicholas (2013). "Russell and Moore's Revolt against British Idealism". In Beaney, Michael (ed.). The Oxford Handbook of The History of Analytic Philosophy. Oxford University Press. doi:10.1093/oxfordhb/9780199238842.013.0024. ISBN 978-0-19-174978-0.
• Grim, Patrick; Rescher, Nicholas (2023). Theory of Categories: Key Instruments of Human Understanding. Anthem Press. ISBN 978-1-83998-815-8. Retrieved 29 March 2024.
• Grütter, Rolf; Bauer-Messmer, Bettina (2007). "Towards Spatial Reasoning in the Semantic Web: A Hybrid Knowledge Representation System Architecture". In Fabrikant, Sara; Wachowicz, Monica (eds.). The European Information Society: Leading the Way with Geo-information. Springer. ISBN 978-3-540-72385-1.
• Gutting, Gary (2009). What Philosophers Know: Case Studies in Recent Analytic Philosophy. Cambridge University Press. ISBN 978-0-521-85621-8.
• Hale, Bob (2020). Essence and Existence. Oxford University Press. ISBN 978-0-19-259622-2. Retrieved 29 March 2024.
• Hameed, Adil; Preece, Alun; Sleeman, Derek (2013). "Ontology Reconciliation". In Staab, Steffen; Studer, Rudi (eds.). Handbook on Ontologies. Springer. ISBN 978-3-540-24750-0.
• Hamlyn, D. W. (2005). "Metaphysics, History of". The Oxford Companion to Philosophy. Oxford University Press. ISBN 978-0-19-926479-7.
• Hancock, Roger (2006). "Metaphysics, History of". In Borchert, Donald M. (ed.). The Encyclopedia of Philosophy. 6: Masaryk – Nussbaum (2 ed.). Thomson Gale, Macmillan Reference. ISBN 978-0-02-865786-8.
• Hanna, Robert (2009). Rationality and Logic. MIT Press. ISBN 978-0-262-26311-5. Retrieved 29 March 2024.
• Hart, W. D. (1998). "Meaning and Verification". Routledge Encyclopedia of Philosophy. Routledge. doi:10.4324/9780415249126-X025-1. ISBN 978-0-415-25069-6. Archived from the original on 2 April 2024. Retrieved 2 April 2024.
• Hawley, Katherine (2016). "Applied Metaphysics". In Lippert-Rasmussen, Kasper; Brownlee, Kimberley; Coady, David (eds.). A Companion to Applied Philosophy. John Wiley & Sons. ISBN 978-1-118-86911-6.
• Hawley, Katherine (2018). "Social Science as a Guide to Social Metaphysics?". Journal for General Philosophy of Science. 49 (2): 187–198. doi:10.1007/s10838-017-9389-5. hdl:10023/12888.
• Hawley, Katherine (2023). "Temporal Parts". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Retrieved 26 March 2024.
• Healey, Richard (2016). "17. Metaphysics in Science". In Humphreys, Paul (ed.). The Oxford Handbook of Philosophy of Science. Oxford University Press. ISBN 978-0-19-063070-6. Retrieved 9 April 2024.
• Heckmann, Dominikus (2006). Ubiquitous User Modeling. IOS Press. ISBN 978-3-89838-297-7.
• Hettche, Matt; Dyck, Corey (2019). "Christian Wolff". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 8 August 2019. Retrieved 2 April 2024.
• Heyndels, Sybren; Bengtson, Audun; Mesel, Benjamin De (2024). "Introduction". P. F. Strawson and His Philosophical Legacy. Oxford University Press. ISBN 978-0-19-285847-4.
• Hoad, T. F. (1993). The Concise Oxford Dictionary of English Etymology. Oxford University Press. ISBN 978-0-19-283098-2.
• Hoefer, Carl; Huggett, Nick; Read, James (2023). "Absolute and Relational Space and Motion: Classical Theories". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Retrieved 26 March 2024.
• Hofweber, Thomas (2023). "Logic and Ontology". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 7 December 2021. Retrieved 20 March 2024.
• Holland, Nancy J. (1999). "Deconstruction". The International Journal of Psycho-Analysis. 80 ( Pt 1): 153–162. doi:10.1516/0020757991598486. PMID 10216822. Retrieved 11 August 2024.
• Hylton, Peter (2007). Quine. Routledge. ISBN 978-1-134-92270-3. Retrieved 4 April 2024.
• Imaguire, Guido (2018). Priority Nominalism: Grounding Ostrich Nominalism as a Solution to the Problem of Universals. Springer. ISBN 978-3-319-95004-4. Retrieved 29 March 2024.
• Jackson, Frank (1998). From Metaphysics to Ethics: A Defence of Conceptual Analysis. Oxford University Press. ISBN 978-0-19-823618-4.
• Jaksland, Rasmus (2023). "Naturalized Metaphysics or Displacing Metaphysicians to Save Metaphysics". Synthese. 201 (6). doi:10.1007/s11229-023-04207-1.
• Janaway, Christopher (1999). "10. The Primacy of Will". Self and World in Schopenhauer's Philosophy. Oxford University Press. ISBN 978-0-19-825003-6. Archived from the original on 2 April 2024. Retrieved 4 April 2024.
• Janiak, Andrew (2022). "Kant's Views on Space and Time". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Retrieved 26 March 2024.
• Jubien, Michael (2004). "Metaphysics". In Shand, John (ed.). Fundamentals of Philosophy. Routledge. ISBN 978-1-134-58831-2. Retrieved 29 March 2024.
• Khlentzos, Drew (2021). "Challenges to Metaphysical Realism". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 26 September 2019. Retrieved 18 March 2024.
• Kim, Jaegwon (2005). "Mind, Problems of the Philosophy of". The Oxford Companion to Philosophy. Oxford University Press. ISBN 978-0-19-926479-7. Archived from the original on 11 April 2024. Retrieved 29 March 2024.
• Kind, Amy (2018). Philosophy of Mind in the Twentieth and Twenty-First Centuries: The History of the Philosophy of Mind. Vol. 6. Routledge. ISBN 978-0-429-01938-8. Retrieved 1 September 2023.
• Kirk, G. S. (2004). "Presocratics". In Rée, Jonathan; Urmson, J. O. (eds.). The Concise Encyclopedia of Western Philosophy. Routledge. ISBN 978-1-134-33177-2. Retrieved 16 June 2023.
• Kirk, Robert (2023). "Zombies". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 28 September 2020. Retrieved 15 March 2024.
• Kirwan, Christopher (2005). "Identity". The Oxford Companion to Philosophy. Oxford University Press. ISBN 978-0-19-926479-7. Archived from the original on 11 April 2024. Retrieved 29 March 2024.
• Klement, Kevin (2019). "Russell's Logical Atomism". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 11 April 2024. Retrieved 2 April 2024.
• Koons, Robert C.; Pickavance, Timothy H. (2015). Metaphysics: The Fundamentals (1. ed.). Wiley-Blackwell. ISBN 978-1-4051-9574-4.
• Korfmacher, Carsten. "Personal Identity". Internet Encyclopedia of Philosophy. Archived from the original on 9 February 2021. Retrieved 28 March 2024.
• Körner, Stephan (1984). Metaphysics: Its Structure and Function. Cambridge University Press. ISBN 978-0-521-26496-9. Retrieved 18 March 2024.
• Kozierkiewicz, Adrianna; Pietranik, Marcin (2019). "A Formal Framework for the Ontology Evolution". In Nguyen, Ngoc Thanh; Gaol, Ford Lumban; Hong, Tzung-Pei; Trawiński, Bogdan (eds.). Intelligent Information and Database Systems: 11th Asian Conference, ACIIDS 2019, Yogyakarta, Indonesia, April 8–11, 2019, Proceedings, Part I. Springer. ISBN 978-3-030-14799-0.
• Kriegel, Uriah (2016). "Philosophy as Total Axiomatics: Serious Metaphysics, Scrutability Bases, and Aesthetic Evaluation". Journal of the American Philosophical Association. 2 (2): 272–290. doi:10.1017/apa.2016.8. Archived from the original on 29 January 2024. Retrieved 11 April 2024.
• Kuhn, Thomas S. (2010). "Possible Worlds in History of Science". In Sture, Allén (ed.). Possible Worlds in Humanities, Arts and Sciences: Proceedings of Nobel Symposium 65. Walter de Gruyter. ISBN 978-3-11-086685-8. Retrieved 29 March 2024.
• Lacey, Alan (2005). "Intuition". The Oxford Companion to Philosophy. Oxford University Press. ISBN 978-0-19-926479-7.
• Lawson, Joanna (2020). "Common Sense in Metaphysics". The Cambridge Companion to Common-Sense Philosophy. Cambridge University Press. ISBN 978-1-108-47600-3. Archived from the original on 18 March 2024. Retrieved 18 March 2024.
• Liston, Michael. "Scientific Realism and Antirealism". Internet Encyclopedia of Philosophy. Archived from the original on 14 March 2024. Retrieved 29 March 2024.
• Littlejohn, Ronnie. "Daoist Philosophy". Internet Encyclopedia of Philosophy. Archived from the original on 29 March 2024. Retrieved 30 March 2024.
• Lizzini, Olga (2021). "Ibn Sina's Metaphysics". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 11 April 2024. Retrieved 2 April 2024.
• Look, Brandon C. (2020). "Gottfried Wilhelm Leibniz". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 5 August 2020. Retrieved 2 April 2024.
• Lorkowski, C. M. "Hume, David: Causation". Internet Encyclopedia of Philosophy. Archived from the original on 27 March 2024. Retrieved 27 March 2024.
• Loux, Michael J.; Crisp, Thomas M. (2017). Metaphysics: A Contemporary Introduction (4 ed.). Routledge. ISBN 978-1-138-63933-1.
• Lowe, E. J. (2005). "Particulars and Non-particulars". The Oxford Companion to Philosophy. Oxford University Press. ISBN 978-0-19-926479-7. Archived from the original on 11 April 2024. Retrieved 29 March 2024.
• Lowe, E. J. (2005a). "Truth". The Oxford Companion to Philosophy. Oxford University Press. ISBN 978-0-19-926479-7. Archived from the original on 11 April 2024. Retrieved 29 March 2024.
• Lowe, E. J. (2013). "Metaphysical Knowledge". In Haug, Matthew C. (ed.). Philosophical Methodology: The Armchair or the Laboratory?. Routledge. ISBN 978-1-135-10703-1.
• Macarthur, David (2020). "Richard Rorty and (the End of) Metaphysics (?)". In Malachowski, Alan (ed.). A Companion to Rorty. John Wiley & Sons. ISBN 978-1-118-97217-5. Retrieved 6 April 2024.
• MacBride, Fraser (2022). "Truthmakers". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Retrieved 26 April 2024.
• MacDonald, Cynthia (2008). Varieties of Things: Foundations of Contemporary Metaphysics. Blackwell Publishing. ISBN 978-1-4051-5444-4.
• MacFarlane, John (2017). "Logical Constants". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 17 March 2020. Retrieved 21 November 2021.
• MacLeod, Mary C.; Rubenstein, Eric M. "Universals". Internet Encyclopedia of Philosophy. Archived from the original on 24 February 2024. Retrieved 24 March 2024.
• Macnamara, John (2009). Through the Rearview Mirror: Historical Reflections on Psychology. MIT Press. ISBN 978-0-262-26367-2. Retrieved 29 March 2024.
• Magnus, P. D. (2005). Forall X: An Introduction to Formal Logic. SUNY Press. ISBN 978-1-64176-026-3. Archived from the original on 7 December 2021. Retrieved 29 December 2021.
• Manley, David (2009). "1. Introduction: A Guided Tour of Metametaphysics". Metametaphysics: New Essays on the Foundations of Ontology. Clarendon Press. ISBN 978-0-19-954604-6.
• Marenbon, John (2009). "Introduction: Reading Boethius Whole". In Marenbon, John (ed.). The Cambridge Companion to Boethius. Cambridge University Press. ISBN 978-1-139-82815-4. Retrieved 4 April 2024.
• Maurin, Anna-Sofia (2019). "Particulars". Routledge Encyclopedia of Philosophy. Routledge. doi:10.4324/9780415249126-N040-2. ISBN 978-0-415-25069-6. Archived from the original on 25 March 2024. Retrieved 29 March 2024.
• McDaniel, Kris (2017). The Fragmentation of Being. Oxford University Press. ISBN 978-0-19-103037-6. Retrieved 1 September 2023.
• McDaniel, Kris (2020). This Is Metaphysics: An Introduction. John Wiley & Sons. ISBN 978-1-118-40077-7. Retrieved 18 March 2024.
• McLaughlin, Brian P. (1999). Audi, Robert (ed.). The Cambridge Dictionary of Philosophy (2 ed.). Cambridge University Press. ISBN 978-0-521-63722-0.
• McLean, G. F. (2003). "Metaphysics". New Catholic Encyclopedia. Gale and Catholic University of America. ISBN 978-0-7876-4013-2. Archived from the original on 9 July 2021. Retrieved 8 July 2021.
• Meinertsen, Bo R. (2018). Metaphysics of States of Affairs: Truthmaking, Universals, and a Farewell to Bradley's Regress. Springer Nature Singapore. ISBN 978-981-13-3068-1.
• Menzel, Christopher (2023). "Possible Worlds". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Retrieved 24 March 2024.
• Miller, Kristie (2018). "Persistence". Routledge Encyclopedia of Philosophy. Routledge. doi:10.4324/0123456789-N126-1. ISBN 978-0-415-25069-6. Archived from the original on 26 March 2024. Retrieved 26 March 2024.
• Misak, Cheryl J. (2008). "Scientific Realism, Anti-Realism, and Empiricism". In Shook, John R.; Margolis, Joseph (eds.). A Companion to Pragmatism. John Wiley & Sons. ISBN 978-1-4051-5311-9. Retrieved 4 April 2024.
• Morris, Michael (2017). "Metaphysics, Philosophy, and the Philosophy of Language". In Hale, Bob; Wright, Crispin; Miller, Alexander (eds.). A Companion to the Philosophy of Language. John Wiley & Sons. ISBN 978-1-118-97208-3. Retrieved 4 April 2024.
• Morris, William Edward; Brown, Charlotte R. (2023). "David Hume". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 3 May 1998. Retrieved 31 March 2024.
• Morton, Adam (2005). "Mind". The Oxford Companion to Philosophy. Oxford University Press. ISBN 978-0-19-926479-7.
• Mumford, Stephen, ed. (2003). "11. The Philosophy of Logical Atomism". Russell on Metaphysics: Selections from the Writings of Bertrand Russell. Routledge. ISBN 978-1-136-90272-7. Retrieved 4 April 2024.
• Mumford, Stephen (2009). "Passing Powers Around". Monist. 92 (1): 94–111. doi:10.5840/monist20099215.
• Mumford, Stephen (2012). Metaphysics: A Very Short Introduction (1 ed.). Oxford University Press. ISBN 978-0-19-965712-4.
• Mumford, Stephen; Anjum, Rani Lill (2013). "8. Primitivism: Is Causation the Most Basic Thing?". Causation: A Very Short Introduction. Oxford University Press. ISBN 978-0-19-968443-4. Retrieved 29 March 2024.
• Mumford, Stephen; Tugby, Matthew (2013). "1. Introduction What Is the Metaphysics of Science?". Metaphysics and Science. Oxford University Press. ISBN 978-0-19-967452-7.
• Nelson, Michael (2022). "Existence". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 3 September 2018. Retrieved 6 August 2023.
• Ney, Alyssa (2014). Metaphysics: An Introduction. Routledge. ISBN 978-0-415-64074-9.
• Noonan, Harold; Curtis, Ben (2022). "Identity". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 23 July 2020. Retrieved 28 March 2024.
• Nuttall, Jon (2013). An Introduction to Philosophy. John Wiley & Sons. ISBN 978-0-7456-6807-9. Retrieved 29 March 2024.
• Oddie, Graham (2006). "Metaphysics". In Borchert, Donald M. (ed.). The Encyclopedia of Philosophy. 6: Masaryk – Nussbaum (2 ed.). Macmillan. ISBN 978-0-02-865786-8.
• Olson, Eric T. (2001). "Mind–Body Problem". In Blakemore, Colin; Jennett, Sheila (eds.). The Oxford Companion to the Body. Oxford University Press. ISBN 978-0-19-852403-8. Archived from the original on 28 March 2024. Retrieved 29 March 2024.
• Olson, Eric T. (2023). "Personal Identity". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Retrieved 28 March 2024.
• O’Connor, Timothy; Franklin, Christopher (2022). "Free Will". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 15 May 2021. Retrieved 28 March 2024.
• Palmer, Clare (1998). Environmental Ethics and Process Thinking. Clarendon Press. ISBN 978-0-19-826952-6. Retrieved 4 April 2024.
• Parent, Ted. "Modal Metaphysics". Internet Encyclopedia of Philosophy. Archived from the original on 11 November 2020. Retrieved 22 March 2024.
• Pavel, Thomas G. (1986). Fictional Worlds. Harvard University Press. ISBN 978-0-674-29966-5. Retrieved 18 February 2024.
• Pelczar, Michael (2015). Sensorama: A Phenomenalist Analysis of Spacetime and Its Contents. Oxford University Press. ISBN 978-0-19-104706-0. Retrieved 29 March 2024.
• Perkins, Franklin (2023). "Metaphysics in Chinese Philosophy". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 1 February 2024. Retrieved 4 April 2024.
• Perrett, Roy W. (2016). An Introduction to Indian Philosophy. Cambridge University Press. ISBN 978-0-521-85356-9. Retrieved 4 April 2024.
• Peters, Michael A. (2021). "2.c Wittgenstein and the Rise of Linguistic Philosophy". Wittgenstein, Education and the Problem of Rationality. Springer Nature Singapore. ISBN 978-981-15-9972-9.
• Pihlström, Sami (2009). Pragmatist Metaphysics: An Essay on the Ethical Grounds of Ontology. A&C Black. ISBN 978-1-84706-593-3. Retrieved 18 March 2024.
• Poidevin, Robin Le; Peter, Simons; Andrew, McGonigal; Cameron, Ross P. (2009). The Routledge Companion to Metaphysics. Routledge. ISBN 978-1-134-15585-9. Retrieved 1 September 2023.
• Politis, Vasilis (2004). Routledge Philosophy Guidebook to Aristotle and the Metaphysics. Routledge. ISBN 978-0-415-25147-1.
• Pols, Edward (1993). "The Metaphor of a Foundation for Knowledge". In Bogaard, Paul A.; Treash, Gordon (eds.). Metaphysics as Foundation: Essays in Honor of Ivor Leclerc. SUNY Press. ISBN 978-0-7914-1258-9.
• Pradhan, Ramesh Chandra (2020). Metaphysics of Consciousness: The Indian Vedantic Perspective. Springer Nature Singapore. ISBN 978-981-15-8064-2.
• Proops, Ian (2022). "Wittgenstein's Logical Atomism". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Retrieved 2 April 2024.
• Pust, Joel (2019). "Intuition". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Retrieved 8 August 2024.
• Ramsey, William (2022). "Eliminative Materialism". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 14 October 2019. Retrieved 27 March 2024.
• Rangaswami, Sudhakshina (2012). The Roots of Vedānta. Penguin Books India. ISBN 978-0-14-306445-9.
• Rea, Michael C. (2021). Metaphysics: The Basics (2 ed.). Routledge. ISBN 978-0-367-13607-9.
• Reynolds, Jack. "Derrida, Jacques". Internet Encyclopedia of Philosophy. Archived from the original on 13 March 2024. Retrieved 2 April 2024.
• Roberts, John T. (2016). "16. Laws of Nature". In Humphreys, Paul (ed.). The Oxford Handbook of Philosophy of Science. Oxford University Press. ISBN 978-0-19-063070-6. Retrieved 9 April 2024.
• Roberts, Austin (2016a). "Divine Differentials: The Metaphysics of Gilles Deleuze and Its Significance for Contemporary Theology". In Shults, F. LeRon; Powell-Jones, Lindsay (eds.). Deleuze and the Schizoanalysis of Religion. Bloomsbury. ISBN 978-1-4742-6690-1.
• Robinet, Isabelle (2013). "Chongxuan". In Pregadio, Fabrizio (ed.). The Encyclopedia of Taoism. Routledge. ISBN 978-1-135-79634-1. Retrieved 4 April 2024.
• Rodriguez-Pereyra, Gonzalo (2000). "What Is the Problem of Universals?". Mind. 109 (434): 255–273. doi:10.1093/mind/109.434.255.
• Romero, Gustavo E. (2018). Scientific Philosophy. Springer. ISBN 978-3-319-97631-0. Retrieved 29 March 2024.
• Ruzsa, Ferenc. "Sankhya". Internet Encyclopedia of Philosophy. Archived from the original on 19 May 2019. Retrieved 30 March 2024.
• Ryckman, Thomas (2005). The Reign of Relativity: Philosophy in Physics 1915–1925. Oxford University Press. ISBN 978-0-19-029215-7. Retrieved 18 March 2024.
• Shaffer, Michael J. (2015). "The Problem of Necessary and Sufficient Conditions and Conceptual Analysis". Metaphilosophy. 46 (4/5): 555–563. doi:10.1111/meta.12158. ISSN 0026-1068. JSTOR 26602327. S2CID 148551744. Archived from the original on 13 February 2022. Retrieved 15 February 2022.
• Shapiro, Stewart; Kouri Kissel, Teresa (2022). "Classical Logic". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 3 May 1998. Retrieved 15 August 2023.
• Shun'ei, Tagawa (2014). Living Yogacara: An Introduction to Consciousness-Only Buddhism. Simon and Schuster. ISBN 978-0-86171-895-5. Retrieved 4 April 2024.
• Sider, Theodore (2009). "13. Ontological Realism". Metametaphysics: New Essays on the Foundations of Ontology. Clarendon Press. ISBN 978-0-19-954604-6.
• Simons, Peter (2013). "The Thread of Persistence". In Kanzian, Christian (ed.). Persistence. Walter de Gruyter. ISBN 978-3-11-032705-2. Retrieved 29 March 2024.
• Sleigh, R. C. (2005). "Identity of Indiscernibles". The Oxford Companion to Philosophy. Oxford University Press. ISBN 978-0-19-926479-7.
• Smart, Ninian (2008). World Philosophies (2 ed.). Routledge. ISBN 978-0-415-41188-2.
• Smith, Daniel; Protevi, John; Voss, Daniela (2023). "Gilles Deleuze". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Retrieved 11 August 2024.
• Stern, Robert; Cheng, Tony (2023). "Transcendental Arguments". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Retrieved 17 March 2024.
• Stuart, David (2016). Practical Ontologies for Information Professionals. Facet Publishing. ISBN 978-1-78330-062-4.
• Stubenberg, Leopold; Wishon, Donovan (2023). "Neutral Monism". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 15 July 2018. Retrieved 27 March 2024.
• Studtmann, Paul (2024). "Aristotle's Categories". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Retrieved 22 March 2024.
• Svare, Helge (2006). Body and Practice in Kant. Springer. ISBN 978-1-4020-4118-1. Retrieved 4 April 2024.
• Sweeney, E. (2016). Logic, Theology and Poetry in Boethius, Anselm, Abelard, and Alan of Lille: Words in the Absence of Things. Palgrave Macmillan. ISBN 978-1-137-06373-1. Retrieved 17 June 2023.
• Tahko, Tuomas E. (2015). An Introduction to Metametaphysics. Cambridge University Press. ISBN 978-1-107-07729-4.
• Tahko, Tuomas (2018). "Meta-metaphysics". Routledge Encyclopedia of Philosophy. Routledge. doi:10.4324/9780415249126-N127-1. hdl:1983/9dafefd5-5280-49b5-9085-de78b6ebb656. ISBN 978-0-415-25069-6. Archived from the original on 20 March 2024. Retrieved 20 March 2024.
• Tallant, Jonathan (2017). Metaphysics: An Introduction (Second ed.). Bloomsbury. ISBN 978-1-3500-0671-3.
• Taminiaux, Jacques (1991). Heidegger and the Project of Fundamental Ontology. State University of New York Press. ISBN 978-1-4384-2179-7. Retrieved 4 April 2024.
• Thomasson, Amie (2022). "Categories". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 8 October 2023. Retrieved 20 March 2024.
• Timpe, Kevin. "Free Will". Internet Encyclopedia of Philosophy. Archived from the original on 6 April 2019. Retrieved 28 March 2024.
• Turner, William (1911). "Metaphysics". Catholic Encyclopedia. Vol. 10. The Encyclopedia Press. OCLC 1391341.
• Van Inwagen, Peter (2023). "Existence". Encyclopedia Britannica. Archived from the original on 29 June 2023. Retrieved 7 August 2023.
• Van Inwagen, Peter (2024). Metaphysics (5 ed.). Routledge. ISBN 978-1-032-40916-0.
• Van Inwagen, Peter; Sullivan, Meghan; Bernstein, Sara (2023). "Metaphysics". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 16 September 2018. Retrieved 17 March 2024.
• Varzi, Achille (2019). "Mereology". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Archived from the original on 28 September 2020. Retrieved 25 March 2024.
• Velez, Abraham. "Buddha". Internet Encyclopedia of Philosophy. Archived from the original on 4 February 2024. Retrieved 30 March 2024.
• Vihvelin, Kadri (2022). "Arguments for Incompatibilism". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Retrieved 1 May 2024.
• Wang, Yueqing; Bao, Qinggang; Guan, Guoxing (2020). "1. Way (Dao, 道)". History of Chinese Philosophy Through Its Key Terms. Nanjing University Press. ISBN 978-981-15-2572-8.
• Wardy, Robert (1998). "Categories". Routledge Encyclopedia of Philosophy. Routledge. doi:10.4324/9780415249126-N005-1. ISBN 978-0-415-25069-6. Archived from the original on 22 March 2024. Retrieved 22 March 2024.
• Weisberg, Josh. "Hard Problem of Consciousness". Internet Encyclopedia of Philosophy. Archived from the original on 19 July 2023. Retrieved 27 March 2024.
• Wheeler, Michael (2020). "Martin Heidegger". The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. Retrieved 11 August 2024.
• White, Alan (2019). Methods of Metaphysics. Routledge. ISBN 978-0-429-51427-2.
• Williamson, John (2012). "Probabilistic Theories". In Beebee, Helen; Hitchcock, Christopher; Menzies, Peter (eds.). The Oxford Handbook of Causation. Oxford University Press. ISBN 978-0-19-162946-4. Retrieved 29 March 2024.
• Wilsch, Tobias (2017). "Sophisticated Modal Primitivism". Philosophical Issues. 27 (1): 428–448. doi:10.1111/phis.12100.
• Wood, Allen W. (2009). "Kantianism". In Kim, Jaekwon; Sosa, Ernest; Rosenkrantz, Gary S. (eds.). A Companion to Metaphysics. John Wiley & Sons. ISBN 978-1-4443-0853-2. Retrieved 21 March 2024.
• Wu, Guo (2022). An Anthropological Inquiry Into Confucianism: Ritual, Emotion, and Rational Principle. Rowman & Littlefield. ISBN 978-1-7936-5432-8. Retrieved 4 April 2024.
• Züricher, Tobias (2021). "Free Will, Responsibility, and Blame in Psychotherapy". In Trachsel, Manuel; Biller-Andorno, Nikola; Gaab, Jens; Tekin, Şerife; Sadler, John Z. (eds.). The Oxford Handbook of Psychotherapy Ethics. Oxford University Press. ISBN 978-0-19-881733-8.

External links

• Metaphysics at PhilPapers
• Metaphysics at the Indiana Philosophy Ontology Project
• "Metaphysics". Internet Encyclopedia of Philosophy.
• Metaphysics at Encyclopædia Britannica
• Metaphysics public domain audiobook at LibriVox