In philosophy, metaphysical necessity, sometimes called broad logical necessity, is one of many different kinds of
necessity
Necessary or necessity may refer to:
* Need
** An action somebody may feel they must do
** An important task or essential thing to do at a particular time or by a particular moment
* Necessary and sufficient condition, in logic, something that i ...
, which sits between logical necessity and
nomological
In philosophy, nomology refers to a "science of laws" based on the theory that it is possible to elaborate descriptions dedicated not to particular aspects of reality but inspired by a scientific vision of universal validity expressed by scientific ...
(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
In logic and linguistics, a proposition is the meaning of a declarative sentence. In philosophy, " meaning" is understood to be a non-linguistic entity which is shared by all sentences with the same meaning. Equivalently, a proposition is the no ...
is said to be ''necessary'' if it could not have failed to be the case.
Nomological
In philosophy, nomology refers to a "science of laws" based on the theory that it is possible to elaborate descriptions dedicated not to particular aspects of reality but inspired by a scientific vision of universal validity expressed by scientific ...
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.
The concept of a metaphysically necessary being plays an important role in certain
arguments for the existence of God
The existence of God (or more generally, the existence of deities) is a subject of debate in theology, philosophy of religion and popular culture. A wide variety of arguments for and against the existence of God or deities can be categorize ...
, especially the
ontological argument
An ontological argument is a philosophical argument, made from an ontological basis, that is advanced in support of the existence of God. Such arguments tend to refer to the state of being or existing. More specifically, ontological arguments ...
, but metaphysical necessity is also one of the central concepts in late 20th century
analytic philosophy
Analytic philosophy is a branch and tradition of philosophy using analysis, popular in the Western world and particularly the Anglosphere, which began around the turn of the 20th century in the contemporary era in the United Kingdom, United Sta ...
. Metaphysical necessity has proved a controversial concept, and criticized by
David Hume
David Hume (; born David Home; 7 May 1711 NS (26 April 1711 OS) – 25 August 1776) Cranston, Maurice, and Thomas Edmund Jessop. 2020 999br>David Hume" ''Encyclopædia Britannica''. Retrieved 18 May 2020. was a Scottish Enlightenment philo ...
,
Immanuel Kant
Immanuel Kant (, , ; 22 April 1724 – 12 February 1804) was a German philosopher and one of the central Enlightenment thinkers. Born in Königsberg, Kant's comprehensive and systematic works in epistemology, metaphysics, ethics, and ...
,
J. L. Mackie
John Leslie Mackie (25 August 1917 – 12 December 1981) was an Australian philosopher. He made significant contributions to the philosophy of religion, metaphysics, and the philosophy of language, and is perhaps best known for his views on m ...
, and
Richard Swinburne
Richard Granville Swinburne (IPA ) (born December 26, 1934) is an English philosopher. He is an Emeritus Professor of Philosophy at the University of Oxford. Over the last 50 years Swinburne has been a proponent of philosophical arguments for t ...
, among others.
Types of necessity
Metaphysical necessity is contrasted with other types of necessity. For example, the philosophers of religion
John Hick
John Harwood Hick (20 January 1922 – 9 February 2012) 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 are ...
and
William L. Rowe distinguished the following three:
# factual necessity (existential necessity): a factually necessary being is not causally dependent on any other being, while any other being is causally dependent on it.
# causal necessity (subsumed by Hick under the former type): a causally necessary being is such that it is logically impossible for it to be causally dependent on any other being, and it is logically impossible for any other being to be causally independent of it.
#
logical necessity
Logical truth is one of the most fundamental concepts in logic. Broadly speaking, a logical truth is a Statement (logic), statement which is truth, true regardless of the truth or falsity of its constituent propositions. In other words, a logical ...
: a logically necessary being is a being whose non-existence is a logical impossibility, and which therefore exists either timeless or eternally in all possible worlds.
Hume's dictum
Hume's dictum is a thesis about necessary connections between distinct entities. Its original formulation can be found in
David Hume
David Hume (; born David Home; 7 May 1711 NS (26 April 1711 OS) – 25 August 1776) Cranston, Maurice, and Thomas Edmund Jessop. 2020 999br>David Hume" ''Encyclopædia Britannica''. Retrieved 18 May 2020. was a Scottish Enlightenment philo ...
's
A Treatise of Human Nature
'' A Treatise of Human Nature: Being an Attempt to Introduce the Experimental Method of Reasoning into Moral Subjects'' (1739–40) is a book by Scottish philosopher David Hume, considered by many to be Hume's most important work and one of the ...
: "There is no object, which implies the existence of any other if we consider these objects in themselves".
Hume's intuition motivating this thesis is that while experience presents us with certain ideas of various objects, it might as well have presented us with very different ideas. So when I perceive a bird on a tree, I might as well have perceived a bird without a tree or a tree without a bird. This is so because their
essences do not depend upon another.
David Lewis follows this line of thought in formulating his ''principle of recombination'': "anything can coexist with anything else, at least provided they occupy distinct spatiotemporal positions. Likewise, anything can fail to coexist with anything else".
Hume's dictum has been employed in various arguments in contemporary
metaphysics
Metaphysics is the branch of philosophy that studies the fundamental nature of reality, the first principles of being, identity and change, space and time, causality, necessity, and possibility. It includes questions about the nature of conscio ...
. It can be used, for example, as an argument against nomological necessitarianism, the view that the
laws of nature are necessary, i.e. are the same in all possible worlds. To see how this might work, consider the case of salt being thrown into a cup of water and subsequently dissolving. This can be described as a series of two events, a throwing-event and a dissolving-event. Necessitarians hold that all possible worlds with the throwing-event also contain a subsequent dissolving-event. But the two events are distinct entities, so according to Hume's dictum, it is possible to have one event without the other. An even wider application is to use Hume's dictum as an axiom of modality to determine which propositions or worlds are possible based on the notion of recombination.
A posteriori and necessary truths
In
Naming and Necessity
''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 ...
,
Saul Kripke
Saul Aaron Kripke (; November 13, 1940 – September 15, 2022) was an American philosopher and logician in the analytic tradition. He was a Distinguished Professor of Philosophy at the Graduate Center of the City University of New York and emerit ...
argued that there were
a posteriori truths, such as "Hesperus is Phosphoros", or "Water is H
2O", that were nonetheless metaphysically necessary.
Necessity in theology
While many theologians (e.g.
Anselm of Canterbury
Anselm of Canterbury, OSB (; 1033/4–1109), also called ( it, Anselmo d'Aosta, link=no) after his birthplace and (french: Anselme du Bec, link=no) after his monastery, was an Italian Benedictine monk, abbot, philosopher and theologian of th ...
,
René Descartes
René Descartes ( or ; ; Latinized: Renatus Cartesius; 31 March 1596 – 11 February 1650) was a French philosopher, scientist, and mathematician, widely considered a seminal figure in the emergence of modern philosophy and science. Mathem ...
, and
Gottfried Leibniz
Gottfried Wilhelm (von) Leibniz . ( – 14 November 1716) was a German polymath active as a mathematician, philosopher, scientist and diplomat. He is one of the most prominent figures in both the history of philosophy and the history of mathem ...
) considered God to be a logically or metaphysically necessary being, Richard Swinburne argued for factual necessity, and
Alvin Plantinga
Alvin Carl Plantinga (born November 15, 1932) is an American analytic philosopher who works primarily in the fields of philosophy of religion, epistemology (particularly on issues involving epistemic justification), and logic.
From 1963 to 198 ...
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.
[Richard Swinburne (2004): ''The Existence of God''. 2nd ed. Oxford: Oxford University Press, p. 96]
See also
*
Ananke
In ancient Greek religion, Ananke (; grc, Ἀνάγκη), from the common noun , "force, constraint, necessity") is the personification of inevitability, compulsion and necessity. She is customarily depicted as holding a spindle. One of the ...
*
Modal logic
Modal logic is a collection of formal systems developed to represent statements about necessity and possibility. It plays a major role in philosophy of language, epistemology, metaphysics, and natural language semantics. Modal logics extend other ...
*
Platonism
Platonism is the philosophy of Plato and philosophical systems closely derived from it, though contemporary platonists do not necessarily accept all of the doctrines of Plato. Platonism had a profound effect on Western thought. Platonism at le ...
*
A priori and a posteriori
("from the earlier") and ("from the later") are Latin phrases used in philosophy to distinguish types of knowledge, justification, or argument by their reliance on empirical evidence or experience. knowledge is independent from current ex ...
References
External links
* {{PhilPapers, category, metaphysical-necessity
* http://www.philosophyonline.co.uk/oldsite/tok/rationalism5.htm
Modal Metaphysicsarticle in the ''
Internet Encyclopedia of Philosophy
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 pape ...
''
Modal Illusionsarticle in the ''
Internet Encyclopedia of Philosophy
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 pape ...
''
Necessity
Reality