In philosophy, metaphysical necessity, sometimes called broad logical necessity,is one of many different kinds of necessity, which sits between logical necessity and nomological (or physical) necessity, in the sense that logical necessity entails metaphysical necessity, but not vice versa, and metaphysical necessity entails physical necessity, but not vice versa. A proposition is said to be necessary if it could not have failed to be the case. Nomological necessity is necessity according to the laws of physics and logical necessity is necessity according to the laws of logic, while metaphysical necessities are necessary in the sense that the world could not possibly have been otherwise. What facts are metaphysically necessary, and on what basis we might view certain facts as metaphysically but not logically necessary are subjects of substantial discussion in contemporary philosophy.
A proposition is a tentative and conjectural relationship between constructs that is stated in a declarative form. An example of a proposition is: “An increase in student intelligence causes an increase in their academic achievement.” This declarative statement does not have to be true, but must be empirically testable using data, so that we can judge whether it is true or false. Propositions are generally derived based on logic (deduction) or empirical observations (induction). Because propositions are associations between abstract constructs, they cannot be tested directly. Instead, they are tested indirectly by examining the relationship between corresponding measures (variables) of those constructs. The empirical formulation of propositions, stated as relationships between variables, is called hypotheses. The term proposition has a broad use in contemporary analytic philosophy. It is used to refer to some or all of the following: the primary bearers of truth-value, the objects of belief and other "propositional attitudes", the referents of that-clauses, and the meanings of declarative sentences. Propositions are the sharable objects of attitudes and the primary bearers of truth and falsity. This stipulation rules out certain candidates for propositions, including thought- and utterance-tokens which are not sharable, and concrete events or facts, which cannot be false.
The concept of a metaphysically necessary being plays an important role in certain arguments for the existence of God, especially the ontological argument, but metaphysical necessity is also one of the central concepts in late 20th century analytic philosophy. Metaphysical necessity has proved a controversial concept, and criticized by David Hume, Immanuel Kant, J. L. Mackie, and Richard Swinburne, among others.
An ontological argument is a philosophical argument for the existence of God that uses ontology. Many arguments fall under the category of the ontological, and they tend to involve arguments about the state of being or existing. More specifically, ontological arguments tend to start with a priori theory about the organization of the universe. If that organizational structure is true, the argument will provide reasons why God must exist.
Analytic philosophy is a style of philosophy that became dominant in the Western world at the beginning of the 20th century. The term can refer to one of several things:
David Hume was a Scottish Enlightenment philosopher, historian, economist, and essayist, who is best known today for his highly influential system of philosophical empiricism, scepticism, and naturalism. Hume's empiricist approach to philosophy places him with John Locke, George Berkeley, Francis Bacon and Thomas Hobbes as a British Empiricist. Beginning with his A Treatise of Human Nature (1738), Hume strove to create a total naturalistic science of man that examined the psychological basis of human nature. Against philosophical rationalists, Hume held that passion rather than reason governs human behaviour. Hume argued against the existence of innate ideas, positing that all human knowledge is founded solely in experience.
Metaphysical necessity is contrasted with other types of necessity. For example, the philosophers of religion John Hickand William L. Rowe distinguished the following three:
John Harwood Hick was a philosopher of religion and theologian born in England who taught in the United States for the larger part of his career. In philosophical theology, he made contributions in the areas of theodicy, eschatology, and Christology, and in the philosophy of religion he contributed to the areas of epistemology of religion and religious pluralism.
William Leonard Rowe was a professor emeritus of philosophy at Purdue University who specialized in the philosophy of religion. His work played a leading role in the "remarkable revival of analytic philosophy of religion since the 1970s". He was noted for his formulation of the evidential argument from evil.
While many theologians (e.g. Anselm of Canterbury, René Descartes, and Gottfried Leibniz) considered God to be a logically or metaphysically necessary being, Richard Swinburne argued for factual necessity, and Alvin Plantinga argues that God is a causally necessary being. Because a factually or causally necessary being does not exist by logical necessity, it does not exist in all logically possible worlds.Therefore, Swinburne used the term "ultimate brute fact" for the existence of God.
Anselm of Canterbury, also called Anselm of Aosta after his birthplace and Anselm of Bec after his monastery, was an Italian Benedictine monk, abbot, philosopher and theologian of the Catholic Church, who held the office of archbishop of Canterbury from 1093 to 1109. After his death, he was canonized as a saint; his feast day is 21 April.
René Descartes was a French philosopher, mathematician, and scientist. A native of the Kingdom of France, he spent about 20 years (1629–1649) of his life in the Dutch Republic after serving for a while in the Dutch States Army of Maurice of Nassau, Prince of Orange and the Stadtholder of the United Provinces. He is generally considered one of the most notable intellectual figures of the Dutch Golden Age.
Alvin Carl Plantinga is a prominent American analytic philosopher who works primarily in the fields of logic, justification, philosophy of religion, and epistemology.
In Naming and Necessity,Saul Kripke argued that there were a posteriori truths, such as Hesperus is Phosphoros, or Water is H₂O, that were nonetheless metaphysically necessary.
Naming and Necessity is a 1980 book with the transcript of three lectures, given by the philosopher Saul Kripke, at Princeton University in 1970, in which he dealt with the debates of proper names in the philosophy of language. The transcript was brought out originally in 1972 in Semantics of Natural Language, edited by Donald Davidson and Gilbert Harman. Among analytic philosophers, Naming and Necessity is widely considered one of the most important philosophical works of the twentieth century.
Saul Aaron Kripke is an American philosopher and logician. He is a Distinguished Professor of Philosophy at the Graduate Center of the City University of New York and emeritus professor at Princeton University. Since the 1960s, Kripke has been a central figure in a number of fields related to mathematical logic, philosophy of language, philosophy of mathematics, metaphysics, epistemology, and set theory. Much of his work remains unpublished or exists only as tape recordings and privately circulated manuscripts. Kripke was the recipient of the 2001 Schock Prize in Logic and Philosophy.
In natural theology and philosophy, a cosmological argument is an argument in which the existence of a unique being, generally seen as some kind of god, is deduced or inferred from facts or alleged facts concerning causation, change, motion, contingency, or finitude in respect of the universe as a whole or processes within it. It is traditionally known as an argument from universal causation, an argument from first cause, or the causal argument, and is more precisely a cosmogonical argument. Whichever term is employed, there are three basic variants of the argument, each with subtle yet important distinctions: the arguments from in causa (causality), in esse (essentiality), and in fieri (becoming).
In philosophy, physicalism is the metaphysical thesis that "everything is physical", that there is "nothing over and above" the physical, or that everything supervenes on the physical. Physicalism is a form of ontological monism—a "one substance" view of the nature of reality as opposed to a "two-substance" (dualism) or "many-substance" (pluralism) view. Both the definition of "physical" and the meaning of physicalism have been debated.
Richard G. Swinburne is a British philosopher. He is an Emeritus Professor of Philosophy at the University of Oxford. Over the last 50 years Swinburne has been an influential proponent of philosophical arguments for the existence of God. His philosophical contributions are primarily in the philosophy of religion and philosophy of science. He aroused much discussion with his early work in the philosophy of religion, a trilogy of books consisting of The Coherence of Theism, The Existence of God, and Faith and Reason.
Modal logic is a type of formal logic primarily developed in the 1960s that extends classical propositional and predicate logic to include operators expressing modality. A modal—a word that expresses a modality—qualifies a statement. For example, the statement "John is happy" might be qualified by saying that John is usually happy, in which case the term "usually" is functioning as a modal. The traditional alethic modalities, or modalities of truth, include possibility, necessity, and impossibility. Other modalities that have been formalized in modal logic include temporal modalities, or modalities of time, deontic modalities, epistemic modalities, or modalities of knowledge and doxastic modalities, or modalities of belief.
The Critique of Pure Reason is a 1781 book by the German philosopher Immanuel Kant, in which the author seeks to determine the limits and scope of metaphysics. A heavily-revised second edition was published in 1787. Also referred to as Kant's "First Critique", it was followed by the Critique of Practical Reason (1788) and the Critique of Judgment (1790). In the preface to the first edition, Kant explains that by a "critique of pure reason" he means not "a critique of books and systems, but of the faculty of reason in general, in respect of all knowledge after which it may strive independently of all experience" and that he aims to reach a decision about "the possibility or impossibility of metaphysics". The First Critique is often viewed as culminating several centuries of early-modern philosophy, and inaugurating modern philosophy.
Hume's fork is an explanation, developed by later philosophers, of David Hume's 1730s division of "relations of ideas" from "matters of fact and real existence". A distinction is made between necessary versus contingent, a priori versus a posteriori, and analytic versus synthetic. Relations of abstract ideas align on one side, whereas concrete truths align on the other.
Logically possible refers to a proposition which can be the logical consequence of another, based on the axioms of a given system of logic. The logical possibility of a proposition will depend on the system of logic being considered, rather than on the violation of any single rule. Some systems of logic restrict inferences from inconsistent propositions or even allow for true contradictions. Other logical systems have more than two truth-values instead of a binary of such values. However, when talking about logical possibility it is often assumed that the system in question is classical propositional logic. Similarly, the criterion for logical possibility is often based on whether or not a proposition is contradictory and as such is often thought of as the broadest type of possibility.
The identity of indiscernibles is an ontological principle that states that there cannot be separate objects or entities that have all their properties in common. That is, entities x and y are identical if every predicate possessed by x is also possessed by y and vice versa; to suppose two things indiscernible is to suppose the same thing under two names. It states that no two distinct things can be exactly alike, but this is intended as a metaphysical principle rather than one of natural science. A related principle is the indiscernibility of identicals, discussed below.
The philosophical zombie or p-zombie argument is a thought experiment in philosophy of mind and philosophy of perception that imagines a being that, if it could conceivably exist, logically disproves the idea that physical stuff is all that is required to explain consciousness. Such a zombie would be indistinguishable from a normal human being but lack conscious experience, qualia, or sentience. For example, if a philosophical zombie were poked with a sharp object it would not inwardly feel any pain, yet it would outwardly behave exactly as if it did feel pain. The argument sometimes takes the form of hypothesizing a zombie world, indistinguishable from our world, but lacking first person experiences in any of the beings of that world.
Subjunctive possibility is the form of modality most frequently studied in modal logic. Subjunctive possibilities are the sorts of possibilities we consider when we conceive of counterfactual situations; subjunctive modalities are modalities that bear on whether a statement might have been or could be true—such as might, could, must, possibly, necessarily, contingently, essentially, accidentally, and so on. Subjunctive possibilities include logical possibility, metaphysical possibility, nomological possibility, and temporal possibility.
Modal realism is the view propounded by David Kellogg Lewis that all possible worlds are real in the same way as is the actual world: they are "of a kind with this world of ours." It is based on the following tenets: possible worlds exist; possible worlds are not different in kind from the actual world; possible worlds are irreducible entities; the term actual in actual world is indexical, i.e. any subject can declare their world to be the actual one, much as they label the place they are "here" and the time they are "now".
In the philosophy of language, the descriptivist theory of proper names is the view that the meaning or semantic content of a proper name is identical to the descriptions associated with it by speakers, while their referents are determined to be the objects that satisfy these descriptions. Bertrand Russell and Gottlob Frege have both been associated with the descriptivist theory, which is sometimes called the Frege–Russell view.
The analytic–synthetic distinction is a semantic distinction, used primarily in philosophy to distinguish propositions into two types: analytic propositions and synthetic propositions. Analytic propositions are true by virtue of their meaning, while synthetic propositions are true by how their meaning relates to the world. However, philosophers have used the terms in very different ways. Furthermore, philosophers have debated whether there is a legitimate distinction.
The Latin phrases a priori and a posteriori are philosophical terms popularized by Immanuel Kant's Critique of Pure Reason, one of the most influential works in the history of philosophy. However, in their Latin forms they appear in Latin translations of Euclid's Elements, of about 300 BC, a work widely considered during the early European modern period as the model for precise thinking.
Two-dimensionalism is an approach to semantics in analytic philosophy. It is a theory of how to determine the sense and reference of a word and the truth-value of a sentence. It is intended to resolve the puzzle: How is it possible to discover empirically that a necessary truth is true? Two-dimensionalism provides an analysis of the semantics of words and sentences that makes sense of this possibility. The theory was first developed by Robert Stalnaker, but it has been advocated by numerous philosophers since, including David Chalmers.
Following the developments in formal logic with symbolic logic in the late nineteenth century and mathematical logic in the twentieth, topics traditionally treated by logic not being part of formal logic have tended to be termed either philosophy of logic or philosophical logic if no longer simply logic.
A posteriori necessity is a thesis in metaphysics and the philosophy of language, that some statements of which we must acquire knowledge a posteriori are also necessarily true. It challenges previously widespread belief that only a priori knowledge can be necessary. It draws on a number of philosophical concepts such as necessity, the causal theory of reference, rigidity, and the a priori a posteriori distinction.
PhilPapers is an international, interactive academic database of journal articles for professionals and students in philosophy. It is maintained by the Centre for Digital Philosophy at the University of Western Ontario.
The Internet Encyclopedia of Philosophy (IEP) is a scholarly online encyclopedia, dealing with philosophy, philosophical topics, and philosophers. The IEP combines open access publication with peer reviewed publication of original papers. Contribution is generally by invitation, and contributors are recognized and leading international specialists within their field.