HOME

TheInfoList



OR:

Hume's fork, in
epistemology Epistemology (; ), or the theory of knowledge, is the branch of philosophy concerned with knowledge. Epistemology is considered a major subfield of philosophy, along with other major subfields such as ethics, logic, and metaphysics. Episte ...
, is a tenet elaborating upon British empiricist philosopher
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 phil ...
's emphatic, 1730s division between "relations of ideas" versus "matters of fact." Antony Flew, ''A Dictionary of Philosophy'', rev 2nd edn (New York: St Martin's Press, 1984)
p. 156
Georges Dicker Georges Dicker is an American philosopher A philosopher is a person who practices or investigates philosophy. The term ''philosopher'' comes from the grc, φιλόσοφος, , translit=philosophos, meaning 'lover of wisdom'. The coining of t ...

ch. 2 "Hume's theory of knowledge (I): 'Hume's fork' "

Hume's Epistemology and Metaphysics: An Introduction
' (London & New York:
Routledge Routledge () is a British multinational publisher. It was founded in 1836 by George Routledge, and specialises in providing academic books, journals and online resources in the fields of the humanities, behavioural science, education, law, ...
, 1998)
p. 41
introducing Kant's formulation of Hume's fork.
(Alternatively, ''Hume's fork'' may refer to what is otherwise termed '' Hume's law'', a tenet of
ethics Ethics or moral philosophy is a branch of philosophy that "involves systematizing, defending, and recommending concepts of right and wrong behavior".''Internet Encyclopedia of Philosophy'' The field of ethics, along with aesthetics, concerns ...
.) As phrased in Immanuel Kant's 1780s characterization of Hume's thesis, and furthered in the 1930s by the logical empiricists, Hume's fork asserts that all statements are exclusively either "analytic ''
a priori ("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 ...
''" or "synthetic ''
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 ...
''," which, respectively, are universally true by mere ''definition'' or, however apparently probable, are unknowable without exact ''experience''.
Georges Dicker Georges Dicker is an American philosopher A philosopher is a person who practices or investigates philosophy. The term ''philosopher'' comes from the grc, φιλόσοφος, , translit=philosophos, meaning 'lover of wisdom'. The coining of t ...

"Hume's fork revisited"
'' History of Philosophy Quarterly'', 1991 Oct;8(4):327–342.
By Hume's fork, a statement's ''
meaning Meaning most commonly refers to: * Meaning (linguistics), meaning which is communicated through the use of language * Meaning (philosophy), definition, elements, and types of meaning discussed in philosophy * Meaning (non-linguistic), a general te ...
'' either is analytic or is
synthetic Synthetic things are composed of multiple parts, often with the implication that they are artificial. In particular, 'synthetic' may refer to: Science * Synthetic chemical or compound, produced by the process of chemical synthesis * Synthetic o ...
, the statement's ''truth''—its agreement with the real world—either is necessary or is contingent, and the statement's purported ''knowledge'' either is or is . An analytic statement is true via its terms' meanings alone, hence true by definition, like ''Bachelors are unmarried'', whereas a synthetic statement, concerning external states of affairs, may be false, like ''Bachelors age badly''. Georges Rey
"The analytic/synthetic distinction"
in Edward N. Zalta, ed., ''
Stanford Encyclopedia of Philosophy The ''Stanford Encyclopedia of Philosophy'' (''SEP'') combines an online encyclopedia of philosophy with peer-reviewed publication of original papers in philosophy, freely accessible to Internet users. It is maintained by Stanford University. E ...
'' (Fall 2018).
By mere logical
validity Validity or Valid may refer to: Science/mathematics/statistics: * Validity (logic), a property of a logical argument * Scientific: ** Internal validity, the validity of causal inferences within scientific studies, usually based on experiments ...
, the necessary is true in all
possible world A possible world is a complete and consistent way the world is or could have been. Possible worlds are widely used as a formal device in logic, philosophy, and linguistics in order to provide a semantics for intensional and modal logic. Their ...
s, whereas the contingent hinges on the world's state, a
metaphysical 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 consci ...
basis. And the ''a priori'' is knowable without, whereas the ''a posteriori'' is knowable only upon, experience in the area of interest. By Hume's fork, sheer conceptual derivations (ostensibly,
logic Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the science of deductively valid inferences or of logical truths. It is a formal science investigating how conclusions follow from premis ...
and mathematics), being analytic, are necessary and ''a priori'', whereas assertions of "real existence" and traits, being synthetic, are contingent and ''a posteriori''. Hume's own, simpler, distinction concerned the
problem of induction First formulated by David Hume, the problem of induction questions our reasons for believing that the future will resemble the past, or more broadly it questions predictions about unobserved things based on previous observations. This inferen ...
—that no amount of examination of cases will logically entail the conformity of unexamined cases—and supported Hume's aim to position
humanism Humanism is a philosophical stance that emphasizes the individual and social potential and agency of human beings. It considers human beings the starting point for serious moral and philosophical inquiry. The meaning of the term "human ...
on par with
empirical science In philosophy, empiricism is an epistemological theory that holds that knowledge or justification comes only or primarily from sensory experience. It is one of several views within epistemology, along with rationalism and skepticism. Empiri ...
while combatting allegedly rampant "sophistry and illusion" by philosophers and religionists. Being a Transcendental Idealist, Kant asserted both the hope of a true
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 ...
, and a literal view of
Newton's law of universal gravitation Newton's law of universal gravitation is usually stated as that every particle attracts every other particle in the universe with a force that is proportional to the product of their masses and inversely proportional to the square of the distanc ...
by defying Hume's fork to declare the "
synthetic a priori Synthetic things are composed of multiple parts, often with the implication that they are artificial. In particular, 'synthetic' may refer to: Science * Synthetic chemical or compound, produced by the process of chemical synthesis * Synthetic o ...
." In the 1930s, the logical empiricists staked Hume's fork.James Fetzer
"Carl Hempel"
in Edward N. Zalta, ed., ''
The Stanford Encyclopedia of Philosophy The ''Stanford Encyclopedia of Philosophy'' (''SEP'') combines an online encyclopedia of philosophy with peer-reviewed publication of original papers in philosophy, freely accessible to Internet users. It is maintained by Stanford University. E ...
'' (Spring 2013).
Yet in the 1950s, W. V. O Quine undermined its analytic/synthetic distinction. And in the 1970s,
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 eme ...
established the necessary ''a posteriori''. Still, Hume's fork is a useful starting point to anchor philosophical scrutiny.


History

Hume's strong empiricism, as in Hume's fork as well as Hume's
problem of induction First formulated by David Hume, the problem of induction questions our reasons for believing that the future will resemble the past, or more broadly it questions predictions about unobserved things based on previous observations. This inferen ...
, was taken as a threat to Newton's theory of motion.
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 aes ...
responded with his
Transcendental Idealism Transcendental idealism is a philosophical system founded by German philosopher Immanuel Kant in the 18th century. Kant's epistemological program is found throughout his '' Critique of Pure Reason'' (1781). By ''transcendental'' (a term that des ...
in his 1781 '' Critique of Pure Reason'', where Kant attributed to the mind a causal role in
sensory experience The theory of sense data is a view in the philosophy of perception, popularly held in the early 20th century by philosophers such as Bertrand Russell, C. D. Broad, H. H. Price, A. J. Ayer, and G. E. Moore. Sense data are taken to be mind-depende ...
by the mind's aligning the environmental input by arranging those
sense data The theory of sense data is a view in the philosophy of perception, popularly held in the early 20th century by philosophers such as Bertrand Russell, C. D. Broad, H. H. Price, A. J. Ayer, and G. E. Moore. Sense data are taken to be mind-de ...
into the experience of space and time. Kant thus reasoned existence of the synthetic ''a priori''—combining meanings of terms with states of facts, yet known true without experience of the particular instance—replacing the two prongs of Hume's fork with a three-pronged-fork thesis (Kant's pitchfork) and thus saving
Newton's law of universal gravitation Newton's law of universal gravitation is usually stated as that every particle attracts every other particle in the universe with a force that is proportional to the product of their masses and inversely proportional to the square of the distanc ...
. In 1919, Newton's theory fell to Einstein's
general theory of relativity General relativity, also known as the general theory of relativity and Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics. ...
. In the late 1920s, the
logical positivists Logical positivism, later called logical empiricism, and both of which together are also known as neopositivism, is a movement in Western philosophy whose central thesis was the verification principle (also known as the verifiability criterion of ...
rejected Kant's synthetic ''a priori'' and asserted Hume's fork, so called, while hinging it at language—the analytic/synthetic division—while presuming that by holding to analyticity, they could develop a
logical syntax In logic, syntax is anything having to do with formal languages or formal systems without regard to any interpretation or meaning given to them. Syntax is concerned with the rules used for constructing, or transforming the symbols and words of ...
entailing both necessity and aprioricity via logic on side and, on the other side, demand empirical verification, altogether restricting philosophical discourse to claims verifiable as either false or true. In the early 1950s,
Willard Van Orman Quine Willard Van Orman Quine (; known to his friends as "Van"; June 25, 1908 – December 25, 2000) was an American philosopher and logician in the analytic tradition, recognized as "one of the most influential philosophers of the twentieth century ...
undermined the analytic/synthetic division by explicating
ontological relativity The inscrutability or indeterminacy of reference (also referential inscrutability) is a thesis by 20th century analytic philosopher Willard Van Orman Quine in his book ''Word and Object''. The main claim of this theory is that any given sentence ca ...
, as every term in any statement has its meaning contingent on a vast network of knowledge and belief, the speaker's conception of the entire world. By the early 1970s,
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 eme ...
established the necessary ''a posteriori'', since if the
Morning Star Morning Star, morning star, or Morningstar may refer to: Astronomy * Morning star, most commonly used as a name for the planet Venus when it appears in the east before sunrise ** See also Venus in culture * Morning star, a name for the star Siri ...
and the Evening Star are the same star, they are the same star by necessity, but this is known true by a human only through relevant experience. Hume's fork remains basic in Anglo-American philosophy. Many deceptions and confusions are foisted by surreptitious or unwitting conversion of a synthetic claim to an analytic claim, rendered true by necessity but merely a tautology, for instance the ''No true Scotsman'' move. Simply put, Hume's fork has limitations. Related concerns are Hume's distinction of demonstrative versus probable reasoning and Hume's law. Hume makes other, important two-category distinctions, such as beliefs versus desires and as impressions versus ideas.


Relations of ideas and matters of fact

The first distinction is between two different areas of human study: :All the objects of human reason or enquiry may naturally be divided into two kinds, to wit, ''relations of ideas'', and ''matters of fact''. Of the first kind are the sciences of
Geometry Geometry (; ) is, with arithmetic, one of the oldest branches of mathematics. It is concerned with properties of space such as the distance, shape, size, and relative position of figures. A mathematician who works in the field of geometry is c ...
,
Algebra Algebra () is one of the areas of mathematics, broad areas of mathematics. Roughly speaking, algebra is the study of mathematical symbols and the rules for manipulating these symbols in formulas; it is a unifying thread of almost all of mathem ...
, and
Arithmetic Arithmetic () is an elementary part of mathematics that consists of the study of the properties of the traditional operations on numbers—addition, subtraction, multiplication, division, exponentiation, and extraction of roots. In the 19th c ...
...''
hich are Ij ( fa, ايج, also Romanized as Īj; also known as Hich and Īch) is a village in Golabar Rural District, in the Central District of Ijrud County, Zanjan Province, Iran Iran, officially the Islamic Republic of Iran, and also ...
''discoverable by the mere operation of thought ... Matters of fact, which are the second object of human reason, are not ascertained in the same manner; nor is our evidence of their truth, however great, of a like nature with the foregoing. ::: — '' An Enquiry Concerning Human Understanding'' ''Enquiry Concerning Human Understanding'', Section IV, Part I. Hume's fork is often stated in such a way that statements are divided up into two types: * Statements about ideas. These are analytic, necessary, and knowable ''
a priori ("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 ...
''. * Statements about the world. These are synthetic, contingent, and knowable ''
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 ...
''. In modern terminology, members of the first group are known as
analytic proposition Generally speaking, analytic (from el, ἀναλυτικός, ''analytikos'') refers to the "having the ability to analyze" or "division into elements or principles". Analytic or analytical can also have the following meanings: Chemistry * A ...
s and members of the latter as
synthetic proposition Synthetic things are composed of multiple parts, often with the implication that they are artificial. In particular, 'synthetic' may refer to: Science * Synthetic chemical or compound, produced by the process of chemical synthesis * Synthetic o ...
s. This terminology comes from
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 aest ...
(Introduction to '' Critique of Pure Reason'', Section IV). Into the first class fall statements such as ''"all bodies are extended"'', ''"all bachelors are unmarried"'', and ideas of mathematics and logic. Into the second class fall statements like ''"the sun rises in the morning"'', and ''"all bodies have mass"''. Hume wants to prove that
certainty Certainty (also known as epistemic certainty or objective certainty) is the epistemic property of beliefs which a person has no rational grounds for doubting. One standard way of defining epistemic certainty is that a belief is certain if and ...
does not exist in science. First, Hume notes that statements of the second type can never be entirely certain, due to the fallibility of our senses, the possibility of deception (see e.g. the modern
brain in a vat In philosophy, the brain in a vat (BIV) is a scenario used in a variety of thought experiments intended to draw out certain features of human conceptions of knowledge, reality, truth, mind, consciousness, and meaning. It is a modern incarnati ...
theory) and other arguments made by philosophical skeptics. It is always possible that any given statement about the world is false. Second, Hume claims that our belief in cause-and-effect relationships between events is not grounded on reason, but rather arises merely by habit or custom. Suppose one states: "Whenever someone on earth lets go of a stone it falls." While we can grant that in every instance thus far when a rock was dropped on Earth it went down, this does not make it logically necessary that in the future rocks will fall when in the same circumstances. Things of this nature rely upon the future conforming to the same principles which governed the past. But that isn't something that we can know based on past experience—all past experience could tell us is that in the past, the future has resembled the past. Third, Hume notes that relations of ideas can be used only to prove other relations of ideas, and mean nothing outside of the context of how they relate to each other, and therefore tell us nothing about the world. Take the statement "An equilateral triangle has three sides of equal length." While some earlier philosophers (most notably
Plato Plato ( ; grc-gre, Πλάτων ; 428/427 or 424/423 – 348/347 BC) was a Greek philosopher born in Athens during the Classical period in Ancient Greece. He founded the Platonist school of thought and the Academy, the first institutio ...
and Descartes) held that logical statements such as these contained the most formal reality, since they are always true and unchanging, Hume held that, while true, they contain no formal reality, because the truth of the statements rests on the definitions of the words involved, and not on actual things in the world, since there is no such thing as a true triangle or exact equality of length in the world. So for this reason, relations of ideas cannot be used to prove matters of fact. The results claimed by Hume as consequences of his fork are drastic. According to him, relations of ideas can be proved with certainty (by using other relations of ideas), however, they don't really mean anything about the world. Since they don't mean anything about the world, relations of ideas cannot be used to prove matters of fact. Because of this, matters of fact have no certainty and therefore cannot be used to prove anything. Only certain things can be used to prove other things for certain, but only things about the world can be used to prove other things about the world. But since we can't cross the fork, nothing is both certain and about the world, only one or the other, and so it is impossible to prove something about the world with certainty. If accepted, Hume's fork makes it pointless to try to prove 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 ...
(for example) as a matter of fact. If God is not literally made up of physical matter, and does not have an observable effect on the world lthough virtually all theists believe that God has an observable effect on the world since they believe it is his creation making a statement about God is not a matter of fact. Therefore, a statement about God must be a relation of ideas. In this case if we prove the statement "God exists," it doesn't really tell us anything about the world; it is just playing with words. It is easy to see how Hume's fork voids the causal argument and 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 ...
for the existence of a non-observable God. However, this does not mean that the validity of Hume's fork would imply that God definitely does not exist, only that it would imply that the existence of God cannot be proven as a matter of fact without worldly evidence. Hume rejected the idea of any meaningful statement that did not fall into this schema, saying:
If we take in our hand any volume; of
divinity Divinity or the divine are things that are either related to, devoted to, or proceeding from a deity.divine< ...
or school
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 ...
, for instance; let us ask, Does it contain any abstract reasoning concerning quantity or number? No. Does it contain any experimental reasoning concerning matter of fact and existence? No. Commit it then to the flames: for it can contain nothing but sophistry and illusion. — '' An Enquiry Concerning Human Understanding''


Notes


References

* {{Hume Concepts in epistemology Concepts in ethics Concepts in logic Concepts in metaphilosophy Concepts in metaphysics Concepts in the philosophy of mind Concepts in the philosophy of science Conceptual distinctions David Hume Determinism Dichotomies Dilemmas Humeanism Philosophical problems