In logic, fuzzy logic is a form of many-valued logic in which the truth value of variables may be any real number
between 0 and 1 both inclusive. It is employed to handle the concept of
partial truth, where the truth value may range between completely true
and completely false. By contrast, in Boolean logic, the truth values of variables may only be the integer values 0 or 1.
Fuzzy logic is based on the observation that people make
decisions based on imprecise and non-numerical information. Fuzzy models
or sets are mathematical means of representing vagueness
and imprecise information (hence the term fuzzy). These models have the
capability of recognising, representing, manipulating, interpreting,
and utilising data and information that are vague and lack certainty.
Classical logic
only permits conclusions that are either true or false. However, there
are also propositions with variable answers, such as one might find when
asking a group of people to identify a color. In such instances, the
truth appears as the result of reasoning from inexact or partial
knowledge in which the sampled answers are mapped on a spectrum.
Both degrees of truth and probabilities range between 0 and 1 and hence may seem similar at first, but fuzzy logic uses degrees of truth as a mathematical model of vagueness, while probability is a mathematical model of ignorance.
Applying truth values
A basic application might characterize various sub-ranges of a continuous variable. For instance, a temperature measurement for anti-lock brakes
might have several separate membership functions defining particular
temperature ranges needed to control the brakes properly. Each function
maps the same temperature value to a truth value in the 0 to 1 range.
These truth values can then be used to determine how the brakes should
be controlled. Fuzzy set theory provides a means for representing uncertainty.
Linguistic variables
In fuzzy logic applications, non-numeric values are often used to facilitate the expression of rules and facts.
A linguistic variable such as age may accept values such as young and its antonym old.
Because natural languages do not always contain enough value terms to
express a fuzzy value scale, it is common practice to modify linguistic
values with adjectives or adverbs. For example, we can use the hedgesrather and somewhat to construct the additional values rather old or somewhat young.
Process
Fuzzify all input values into fuzzy membership functions.
Execute all applicable rules in the rulebase to compute the fuzzy output functions.
De-fuzzify the fuzzy output functions to get "crisp" output values.
Fuzzification
Fuzzification
is the process of assigning the numerical input of a system to fuzzy
sets with some degree of membership. This degree of membership may be
anywhere within the interval [0,1]. If it is 0 then the value does not
belong to the given fuzzy set, and if it is 1 then the value completely
belongs within the fuzzy set. Any value between 0 and 1 represents the
degree of uncertainty that the value belongs in the set. These fuzzy
sets are typically described by words, and so by assigning the system
input to fuzzy sets, we can reason with it in a linguistically natural
manner.
For example, in the image below the meanings of the expressions cold, warm, and hot
are represented by functions mapping a temperature scale. A point on
that scale has three "truth values"—one for each of the three functions.
The vertical line in the image represents a particular temperature that
the three arrows (truth values) gauge. Since the red arrow points to
zero, this temperature may be interpreted as "not hot"; i.e. this
temperature has zero membership in the fuzzy set "hot". The orange arrow
(pointing at 0.2) may describe it as "slightly warm" and the blue arrow
(pointing at 0.8) "fairly cold". Therefore, this temperature has 0.2
membership in the fuzzy set "warm" and 0.8 membership in the fuzzy set
"cold". The degree of membership assigned for each fuzzy set is the
result of fuzzification.
Fuzzy logic temperature
Fuzzy sets
are often defined as triangle or trapezoid-shaped curves, as each value
will have a slope where the value is increasing, a peak where the value
is equal to 1 (which can have a length of 0 or greater) and a slope
where the value is decreasing. They can also be defined using a sigmoid function. One common case is the standard logistic function defined as
which has the following symmetry property
From this it follows that
Fuzzy logic operators
Fuzzy logic works with membership values in a way that mimics Boolean logic. To this end, replacements for basic operators AND, OR, NOT must be available. There are several ways to this. A common replacement is called the Zadeh operators:
Boolean
Fuzzy
AND(x,y)
MIN(x,y)
OR(x,y)
MAX(x,y)
NOT(x)
1 – x
For TRUE/1 and FALSE/0, the fuzzy expressions produce the same result as the Boolean expressions.
There are also other operators, more linguistic in nature, called hedges that can be applied. These are generally adverbs such as very, or somewhat, which modify the meaning of a set using a mathematical formula.
However, an arbitrary choice table does not always define a fuzzy logic function. In the paper,
a criterion has been formulated to recognize whether a given choice
table defines a fuzzy logic function and a simple algorithm of fuzzy
logic function synthesis has been proposed based on introduced concepts
of constituents of minimum and maximum. A fuzzy logic function
represents a disjunction of constituents of minimum, where a constituent
of minimum is a conjunction of variables of the current area greater
than or equal to the function value in this area (to the right of the
function value in the inequality, including the function value).
Another set of AND/OR operators is based on multiplication, where
x AND y = x*y
NOT x = 1 - x
Hence,
x OR y = NOT( AND( NOT(x), NOT(y) ) )
x OR y = NOT( AND(1-x, 1-y) )
x OR y = NOT( (1-x)*(1-y) )
x OR y = 1-(1-x)*(1-y)
Given any two of AND/OR/NOT, it is possible to derive the third. The generalization of AND is known as a t-norm.
IF-THEN rules
IF-THEN rules map input or computed truth values to desired output truth values. Example:
IF temperature IS very cold THEN fan_speed is stopped
IF temperature IS cold THEN fan_speed is slow
IF temperature IS warm THEN fan_speed is moderate
IF temperature IS hot THEN fan_speed is high
Given a certain temperature, the fuzzy variable hot has a certain truth value, which is copied to the high variable.
Should an output variable occur in several THEN parts, then the
values from the respective IF parts are combined using the OR operator.
Defuzzification
The goal is to get a continuous variable from fuzzy truth values.
This would be easy if the output truth values were exactly those obtained from fuzzification of a given number.
Since, however, all output truth values are computed independently, in most cases they do not represent such a set of numbers.
One has then to decide for a number that matches best the "intention"
encoded in the truth value.
For example, for several truth values of fan_speed, an actual speed must
be found that best fits the computed truth values of the variables
'slow', 'moderate' and so on.
There is no single algorithm for this purpose.
A common algorithm is
For each truth value, cut the membership function at this value
Combine the resulting curves using the OR operator
Find the center-of-weight of the area under the curve
The x position of this center is then the final output.
Forming a consensus of inputs and fuzzy rules
Since
the fuzzy system output is a consensus of all of the inputs and all of
the rules, fuzzy logic systems can be well behaved when input values are
not available or are not trustworthy. Weightings can be optionally
added to each rule in the rulebase and weightings can be used to
regulate the degree to which a rule affects the output values. These
rule weightings can be based upon the priority, reliability or
consistency of each rule. These rule weightings may be static or can be
changed dynamically, even based upon the output from other rules.
Early applications
Many
of the early successful applications of fuzzy logic were implemented in
Japan. The first notable application was on the subway train in Sendai, in which fuzzy logic was able to improve the economy, comfort, and precision of the ride. It has also been used in recognition of hand-written symbols
in Sony pocket computers, flight aid for helicopters, controlling of
subway systems in order to improve driving comfort, precision of
halting, and power economy, improved fuel consumption for automobiles,
single-button control for washing machines, automatic motor control for
vacuum cleaners with recognition of surface condition and degree of
soiling, and prediction systems for early recognition of earthquakes
through the Institute of Seismology Bureau of Meteorology, Japan.
Current applications
In medical decision making
Fuzzy
logic is an important concept when it comes to medical decision making.
Since medical and healthcare data can be subjective or fuzzy,
applications in this domain have a great potential to benefit a lot by
using fuzzy logic based approaches. One of the common application areas
that use fuzzy logic is computer-aided diagnosis (CAD) in medicine.
CAD is a computerized set of inter-related tools that can be used to
aid physicians in their diagnostic decision-making. For example, when a
physician finds a lesion that is abnormal but still at a very early
stage of development he/she may use a CAD approach to characterize the
lesion and diagnose its nature. Fuzzy logic can be highly appropriate to
describe key characteristics of this lesion. Fuzzy logic can be used in
many different aspects within the CAD framework.
The biggest question in this application area is how much useful
information can be derived when using fuzzy logic. A major challenge is
how to derive the required fuzzy data. This is even more challenging
when one has to elicit such data from humans (usually, patients). As it
said "The envelope of what can be achieved and what cannot be achieved
in medical diagnosis, ironically, is itself a fuzzy one" [Seven
Challenges, 2019]. How to elicit fuzzy data, and how to validate the
accuracy of the data is still an ongoing effort strongly related to the
application of fuzzy logic. The problem of assessing the quality of
fuzzy data is a difficult one. This is why fuzzy logic is a highly
promising possibility within the CAD application area but still requires
more research to achieve its full potential.
Although the concepts of using fuzzy logic in CAD is exciting, there
are still several challenges that fuzzy approaches face within the CAD
framework.
Basic propositional fuzzy logic
BL is an extension of MTL logic where conjunction is defined by a
continuous t-norm, and implication is also defined as the residuum of
the t-norm. Its models correspond to BL-algebras.
Łukasiewicz fuzzy logic
is the extension of basic fuzzy logic BL where standard conjunction is
the Łukasiewicz t-norm. It has the axioms of basic fuzzy logic plus an
axiom of double negation, and its models correspond to MV-algebras.
Gödel fuzzy logic is the extension of basic fuzzy logic BL where conjunction is the Gödel
t-norm (that is, minimum). It has the axioms of BL plus an axiom of
idempotence of conjunction, and its models are called G-algebras.
Product fuzzy logic is the extension of basic fuzzy logic BL where
conjunction is the product t-norm. It has the axioms of BL plus another
axiom for cancellativity of conjunction, and its models are called
product algebras.
Fuzzy logic with evaluated syntax (sometimes also called Pavelka's
logic), denoted by EVŁ, is a further generalization of mathematical
fuzzy logic. While the above kinds of fuzzy logic have traditional
syntax and many-valued semantics, in EVŁ syntax is also evaluated. This
means that each formula has an evaluation. Axiomatization of EVŁ stems
from Łukasziewicz fuzzy logic. A generalization of the classical Gödel
completeness theorem is provable in EVŁ.
Predicate fuzzy logics
These extend the above-mentioned fuzzy logics by adding universal and existential quantifiers in a manner similar to the way that predicate logic is created from propositional logic. The semantics of the universal quantifier in t-norm fuzzy logics is the infimum of the truth degrees of the instances of the quantified subformula while the semantics of the existential quantifier is the supremum of the same.
Decidability issues for fuzzy logic
The notions of a "decidable subset" and "recursively enumerable subset" are basic ones for classical mathematics and classical logic. Thus the question of a suitable extension of them to fuzzy set theory is a crucial one. A first proposal in such a direction was made by E.S. Santos by the notions of fuzzy Turing machine, Markov normal fuzzy algorithm and fuzzy program
(see Santos 1970). Successively, L. Biacino and G. Gerla argued that
the proposed definitions are rather questionable. For example, in one shows that the fuzzy Turing machines are not adequate for fuzzy
language theory since there are natural fuzzy languages intuitively
computable that cannot be recognized by a fuzzy Turing Machine. Then
they proposed the following definitions. Denote by Ü the set of rational numbers in [0,1]. Then a fuzzy subset s : S[0,1] of a set S is recursively enumerable if a recursive map h : S×NÜ exists such that, for every x in S, the function h(x,n) is increasing with respect to n and s(x) = lim h(x,n).
We say that s is decidable if both s and its complement –s
are recursively enumerable. An extension of such a theory to the
general case of the L-subsets is possible (see Gerla 2006).
The proposed definitions are well related with fuzzy logic. Indeed, the
following theorem holds true (provided that the deduction apparatus of
the considered fuzzy logic satisfies some obvious effectiveness
property).
Any "axiomatizable" fuzzy theory is recursively enumerable. In particular, the fuzzy set
of logically true formulas is recursively enumerable in spite of the
fact that the crisp set of valid formulas is not recursively enumerable,
in general. Moreover, any axiomatizable and complete theory is
decidable.
It is an open question to give support for a "Church thesis" for fuzzy mathematics,
the proposed notion of recursive enumerability for fuzzy subsets is the
adequate one. In order to solve this, an extension of the notions of
fuzzy grammar and fuzzy Turing machine are necessary. Another open question is to start from this notion to find an extension of Gödel's theorems to fuzzy logic.
Fuzzy databases
Once fuzzy relations are defined, it is possible to develop fuzzy relational databases. The first fuzzy relational database, FRDB, appeared in Maria Zemankova's
dissertation (1983). Later, some other models arose like the
Buckles-Petry model, the Prade-Testemale Model, the Umano-Fukami model
or the GEFRED model by J.M. Medina, M.A. Vila et al.
Fuzzy querying languages have been defined, such as the SQLf by P. Bosc et al. and the FSQL
by J. Galindo et al. These languages define some structures in order to
include fuzzy aspects in the SQL statements, like fuzzy conditions,
fuzzy comparators, fuzzy constants, fuzzy constraints, fuzzy thresholds,
linguistic labels etc.
Comparison to probability
Fuzzy
logic and probability address different forms of uncertainty. While
both fuzzy logic and probability theory can represent degrees of certain
kinds of subjective belief, fuzzy set theory
uses the concept of fuzzy set membership, i.e., how much an observation
is within a vaguely defined set, and probability theory uses the
concept of subjective probability, i.e., frequency of occurrence or likelihood of some event or condition. The concept of fuzzy sets was developed in the mid-twentieth century at Berkeley as a response to the lacking of probability theory for jointly modelling uncertainty and vagueness.
Bart Kosko claims in Fuzziness vs. Probability
that probability theory is a subtheory of fuzzy logic, as questions of
degrees of belief in mutually-exclusive set membership in probability
theory can be represented as certain cases of non-mutually-exclusive
graded membership in fuzzy theory. In that context, he also derives Bayes' theorem from the concept of fuzzy subsethood. Lotfi A. Zadeh
argues that fuzzy logic is different in character from probability, and
is not a replacement for it. He fuzzified probability to fuzzy
probability and also generalized it to possibility theory.
More generally, fuzzy logic is one of many different extensions
to classical logic intended to deal with issues of uncertainty outside
of the scope of classical logic, the inapplicability of probability
theory in many domains, and the paradoxes of Dempster–Shafer theory.
Relation to ecorithms
Computational theorist Leslie Valiant uses the term ecorithms to describe how many less exact systems and techniques like fuzzy logic (and "less robust" logic) can be applied to learning algorithms.
Valiant essentially redefines machine learning as evolutionary. In
general use, ecorithms are algorithms that learn from their more complex
environments (hence eco-) to generalize, approximate and
simplify solution logic. Like fuzzy logic, they are methods used to
overcome continuous variables or systems too complex to completely
enumerate or understand discretely or exactly.
Ecorithms and fuzzy logic also have the common property of dealing with
possibilities more than probabilities, although feedback and feed forward, basically stochastic weights, are a feature of both when dealing with, for example, dynamical systems.
Compensatory fuzzy logic
Compensatory
fuzzy logic (CFL) is a branch of fuzzy logic with modified rules for
conjunction and disjunction. When the truth value of one component of a
conjunction or disjunction is increased or decreased, the other
component is decreased or increased to compensate. This increase or
decrease in truth value may be offset by the increase or decrease in
another component. An offset may be blocked when certain thresholds are
met. Proponents claim that CFL allows for better computational semantic behaviors and mimic natural language.
Compensatory fuzzy logic consists of four continuous operators:
conjunction (c); disjunction (d); fuzzy strict order (or); and negation
(n). The conjunction is the geometric mean and its dual as conjunctive
and disjunctive operators.
IEEE STANDARD 1855–2016 – IEEE Standard for Fuzzy Markup Language
The IEEE 1855, the IEEE STANDARD 1855–2016, is about a specification language named Fuzzy Markup Language (FML) developed by the IEEE Standards Association.
FML allows modelling a fuzzy logic system in a human-readable and
hardware independent way. FML is based on eXtensible Markup Language (XML).
The designers of fuzzy systems with FML have a unified and high-level
methodology for describing interoperable fuzzy systems. IEEE STANDARD
1855–2016 uses the W3CXML Schema definition language to define the syntax and semantics of the FML programs.
Prior to the introduction of FML, fuzzy logic practitioners could
exchange information about their fuzzy algorithms by adding to their
software functions the ability to read, correctly parse, and store the
result of their work in a form compatible with the Fuzzy Control Language (FCL) described and specified by Part 7 of IEC 61131.
In analytic philosophy, philosophy of language investigates the nature of language, the relations between language, language users, and the world. Investigations may include inquiry into the nature of meaning, intentionality, reference, the constitution of sentences, concepts, learning, and thought.
In the West, inquiry into language stretches back to the 5th century BC with Socrates, Plato, Aristotle, and the Stoics. Both in India and in Greece, linguistic speculation predates the emergence of grammatical traditions of systematic description of language, which emerged around the 5th century BC in India (see Yāska), and around the 3rd century BC in Greece (see Rhianus).
In the dialogue Cratylus, Plato considered the question of whether the names of things were determined by convention or by nature. He criticized conventionalism
because it led to the bizarre consequence that anything can be
conventionally denominated by any name. Hence, it cannot account for the
correct or incorrect application of a name. He claimed that there was a
natural correctness to names. To do this, he pointed out that compound words and phrases have a range of correctness. He also argued that primitive names had a natural correctness, because each phoneme represented basic ideas or sentiments. For example, for Plato the letter l and its sound represented the idea of softness. However, by the end of the Cratylus,
he had admitted that some social conventions were also involved, and
that there were faults in the idea that phonemes had individual
meanings. Plato is often considered a proponent of extreme realism.
Aristotle interested himself with the issues of logic, categories, and meaning creation. He separated all things into categories of species and genus. He thought that the meaning of a predicate
was established through an abstraction of the similarities between
various individual things. This theory later came to be called nominalism.
However, since Aristotle took these similarities to be constituted by a
real commonality of form, he is more often considered a proponent of "moderate realism".
The Stoic philosophers made important contributions to the analysis of grammar, distinguishing five parts of speech: nouns, verbs, appellatives (names or epithets), conjunctions and articles. They also developed a sophisticated doctrine of the lektón associated with each sign of a language, but distinct from both the sign itself and the thing to which it refers. This lektón was the meaning (or sense) of every term. The complete lektón of a sentence is what we would now call its proposition. Only propositions were considered "truth-bearers"
or "truth-vehicles" (i.e., they could be called true or false) while
sentences were simply their vehicles of expression. Different lektá could also express things besides propositions, such as commands, questions and exclamations.
Medieval philosophy
Medieval philosophers were greatly interested in the subtleties of language and its usage. For many scholastics, this interest was provoked by the necessity of translating Greek texts into Latin.
There were several noteworthy philosophers of language in the medieval
period. According to Peter J. King, (although this has been disputed), Peter Abelard anticipated the modern theories of reference. Also, William of Ockham's Summa Logicae brought forward one of the first serious proposals for codifying a mental language.
The scholastics of the high medieval period, such as Ockham and John Duns Scotus, considered logic to be a scientia sermocinalis
(science of language). The result of their studies was the elaboration
of linguistic-philosophical notions whose complexity and subtlety has
only recently come to be appreciated. Many of the most interesting
problems of modern philosophy of language were anticipated by medieval
thinkers. The phenomena of vagueness and ambiguity were analyzed
intensely, and this led to an increasing interest in problems related to
the use of syncategorematic words such as and, or, not, if, and every. The study of categorematic words (or terms) and their properties was also developed greatly. One of the major developments of the scholastics in this area was the doctrine of the suppositio. The supposition of a term is the interpretation that is given of it in a specific context. It can be proper or improper (as when it is used in metaphor, metonyms
and other figures of speech). A proper suppositio, in turn, can be
either formal or material accordingly when it refers to its usual
non-linguistic referent (as in "Charles is a man"), or to itself as a
linguistic entity (as in "Charles has seven letters"). Such a classification scheme is the precursor of modern distinctions between use and mention, and between language and metalanguage.
There is a tradition called speculative grammar which existed
from the 11th to the 13th century. Leading scholars included, among
others, Martin of Dacia and Thomas of Erfurt.
In the early 19th century, the Danish philosopher Søren Kierkegaard insisted that language ought to play a larger role in Western philosophy.
He argues that philosophy has not sufficiently focused on the role
language plays in cognition and that future philosophy ought to proceed
with a conscious focus on language:
If the claim of philosophers to be
unbiased were all it pretends to be, it would also have to take account
of language and its whole significance in relation to speculative
philosophy ... Language is partly something originally given, partly
that which develops freely. And just as the individual can never reach
the point at which he becomes absolutely independent ... so too with
language.
Contemporary philosophy
The phrase "linguistic turn" was used to describe the noteworthy emphasis that contemporary philosophers put upon language.
Language began to play a central role in Western philosophy in
the early 20th century. One of the central figures involved in this
development was the German philosopher Gottlob Frege, whose work on philosophical logic and the philosophy of language in the late 19th century influenced the work of 20th-century analytic philosophersBertrand Russell and Ludwig Wittgenstein. The philosophy of language became so pervasive that for a time, in analytic philosophy circles, philosophy as a whole was understood to be a matter of philosophy of language.
Firstly, this field of study seeks to better understand what speakers and listeners do with language in communication, and how it is used socially. Specific interests include the topics of language learning, language creation, and speech acts.
Secondly, the question of how language relates to the minds of both the speaker and the interpreter is investigated. Of specific interest is the grounds for successful translation of words and concepts into their equivalents in another language.
Composition and parts
It has long been known that there are different parts of speech. One part of the common sentence is the lexical word, which is composed of nouns, verbs, and adjectives. A major question in the field – perhaps the single most important question for formalist and structuralist thinkers – is, "How does the meaning of a sentence emerge out of its parts?"
Example of a syntactic tree
Many aspects of the problem of the composition of sentences are addressed in the field of linguistics of syntax. Philosophical semantics tends to focus on the principle of compositionality
to explain the relationship between meaningful parts and whole
sentences. The principle of compositionality asserts that a sentence can
be understood on the basis of the meaning of the parts of the sentence (i.e., words, morphemes) along with an understanding of its structure (i.e., syntax, logic). Further, syntactic propositions are arranged into 'discourse' or 'narrative' structures, which also encode meanings through pragmatics like temporal relations and pronominals.
It is possible to use the concept of functions to describe
more than just how lexical meanings work: they can also be used to
describe the meaning of a sentence. Take, for a moment, the sentence
"The horse is red". We may consider "the horse" to be the product of a propositional function. A propositional function is an operation of language that takes an entity (in this case, the horse) as an input and outputs a semantic fact
(i.e., the proposition that is represented by "The horse is red"). In
other words, a propositional function is like an algorithm. The meaning
of "red" in this case is whatever takes the entity "the horse" and turns
it into the statement, "The horse is red."
Linguists have developed at least two general methods of
understanding the relationship between the parts of a linguistic string
and how it is put together: syntactic and semantic trees. Syntactic trees draw upon the words of a sentence with the grammar of the sentence in mind. Semantic trees, on the other hand, focus upon the role of the meaning of the words and how those meanings combine to provide insight onto the genesis of semantic facts.
Mind and language
Innateness and learning
Some of the major issues at the intersection of philosophy of language and philosophy of mind are also dealt with in modern psycholinguistics. Some important questions are How
much of language is innate? Is language acquisition a special faculty
in the mind? What is the connection between thought and language?
There are three general perspectives on the issue of language learning. The first is the behaviorist
perspective, which dictates that not only is the solid bulk of language
learned, but it is learned via conditioning. The second is the hypothesis testing perspective,
which understands the child's learning of syntactic rules and meanings
to involve the postulation and testing of hypotheses, through the use of
the general faculty of intelligence. The final candidate for
explanation is the innatist
perspective, which states that at least some of the syntactic settings
are innate and hardwired, based on certain modules of the mind.
There are varying notions of the structure of the brain when it comes to language. Connectionist models emphasize the idea that a person's lexicon and their thoughts operate in a kind of distributed, associative network. Nativist models assert that there are specialized devices in the brain that are dedicated to language acquisition. Computation models emphasize the notion of a representational language of thought and the logic-like, computational processing that the mind performs over them. Emergentist models focus on the notion that natural faculties are a complex system that emerge from simpler biological parts. Reductionist
models attempt to explain higher-level mental processes in terms of the
basic low-level neurophysiological activity of the brain.
Language and thought
An important problem which touches both philosophy of language and philosophy of mind
is to what extent language influences thought and vice versa. There
have been a number of different perspectives on this issue, each
offering a number of insights and suggestions.
Linguists Sapir and Whorf
suggested that language limited the extent to which members of a
"linguistic community" can think about certain subjects (a hypothesis
paralleled in George Orwell's novel Nineteen Eighty-Four). In other words, language was analytically prior to thought. Philosopher Michael Dummett is also a proponent of the "language-first" viewpoint.
The stark opposite to the Sapir–Whorf position is the notion that
thought (or, more broadly, mental content) has priority over language.
The "knowledge-first" position can be found, for instance, in the work
of Paul Grice. Further, this view is closely associated with Jerry Fodor and his language of thought
hypothesis. According to his argument, spoken and written language
derive their intentionality and meaning from an internal language
encoded in the mind.
The main argument in favor of such a view is that the structure of
thoughts and the structure of language seem to share a compositional,
systematic character. Another argument is that it is difficult to
explain how signs and symbols on paper can represent anything meaningful
unless some sort of meaning is infused into them by the contents of the
mind. One of the main arguments against is that such levels of language
can lead to an infinite regress. In any case, many philosophers of mind and language, such as Ruth Millikan, Fred Dretske and Fodor, have recently turned their attention to explaining the meanings of mental contents and states directly.
Another tradition of philosophers has attempted to show that
language and thought are coextensive – that there is no way of
explaining one without the other. Donald Davidson, in his essay "Thought
and Talk", argued that the notion of belief could only arise as a
product of public linguistic interaction. Daniel Dennett holds a similar interpretationist view of propositional attitudes. To an extent, the theoretical underpinnings to cognitive semantics (including the notion of semantic framing) suggest the influence of language upon thought.
However, the same tradition views meaning and grammar as a function of
conceptualization, making it difficult to assess in any straightforward
way.
Some thinkers, like the ancient sophist Gorgias, have questioned whether or not language was capable of capturing thought at all.
...speech can never exactly
represent perceptibles, since it is different from them, and
perceptibles are apprehended each by the one kind of organ, speech by
another. Hence, since the objects of sight cannot be presented to any
other organ but sight, and the different sense-organs cannot give their
information to one another, similarly speech cannot give any information
about perceptibles. Therefore, if anything exists and is comprehended,
it is incommunicable.
There are studies that prove that languages shape how people understand causality. Some of them were performed by Lera Boroditsky. For example, English speakers tend to say things like "John broke the vase" even for accidents. However, Spanish or Japanese speakers would be more likely to say "the vase broke itself". In studies conducted by Caitlin Fausey at Stanford University
speakers of English, Spanish and Japanese watched videos of two people
popping balloons, breaking eggs and spilling drinks either intentionally
or accidentally. Later everyone was asked whether they could remember
who did what. Spanish and Japanese speakers did not remember the agents
of accidental events as well as did English speakers.
Russian
speakers, who make an extra distinction between light and dark blue in
their language, are better able to visually discriminate shades of blue.
The Piraha, a tribe in Brazil, whose language has only terms like few and many instead of numerals, are not able to keep track of exact quantities.
In one study German and Spanish speakers were asked to describe objects having opposite gender assignment in those two languages. The descriptions they gave differed in a way predicted by grammatical gender. For example, when asked to describe a "key"—a word that is masculine in German and feminine in Spanish—the German
speakers were more likely to use words like "hard", "heavy", "jagged",
"metal", "serrated" and "useful" whereas Spanish speakers were more
likely to say "golden", "intricate", "little", "lovely", "shiny" and
"tiny". To describe a "bridge", which is feminine in German and
masculine in Spanish, the German speakers said "beautiful", "elegant",
"fragile", "peaceful", "pretty" and "slender", and the Spanish speakers
said "big", "dangerous", "long", "strong", "sturdy" and "towering". This
was the case even though all testing was done in English, a language
without grammatical gender.
In a series of studies conducted by Gary Lupyan, people were asked to look at a series of images of imaginary aliens.
Whether each alien was friendly or hostile was determined by certain
subtle features but participants were not told what these were. They had
to guess whether each alien was friendly or hostile, and after each
response they were told if they were correct or not, helping them learn
the subtle cues that distinguished friend from foe. A quarter of the
participants were told in advance that the friendly aliens were called
"leebish" and the hostile ones "grecious", while another quarter were
told the opposite. For the rest, the aliens remained nameless. It was
found that participants who were given names for the aliens learned to
categorize the aliens far more quickly, reaching 80 per cent accuracy in
less than half the time taken by those not told the names. By the end
of the test, those told the names could correctly categorize 88 per cent
of aliens, compared to just 80 per cent for the rest. It was concluded
that naming objects helps us categorize and memorize them.
In another series of experiments a group of people was asked to view furniture from an IKEA
catalog. Half the time they were asked to label the object – whether it
was a chair or lamp, for example – while the rest of the time they had
to say whether or not they liked it. It was found that when asked to
label items, people were later less likely to recall the specific
details of products, such as whether a chair had arms or not. It was
concluded that labeling objects helps our minds build a prototype of the
typical object in the group at the expense of individual features.
Meaning
The topic that has received the most attention in the philosophy of language has been the nature
of meaning, to explain what "meaning" is, and what we mean when we talk
about meaning. Within this area, issues include: the nature of synonymy,
the origins of meaning itself, our apprehension of meaning, and the
nature of composition (the question of how meaningful units of language
are composed of smaller meaningful parts, and how the meaning of the
whole is derived from the meaning of its parts).
There have been several distinctive explanations of what a linguistic "meaning" is. Each has been associated with its own body of literature.
The ideational theory of meaning, most commonly associated with the British empiricistJohn Locke, claims that meanings are mental representations provoked by signs.
Although this view of meaning has been beset by a number of problems
from the beginning (see the main article for details), interest in it
has been renewed by some contemporary theorists under the guise of semantic internalism.
The truth-conditional theory of meaning holds meaning to be the conditions under which an expression may be true or false. This tradition goes back at least to Frege and is associated with a rich body of modern work, spearheaded by philosophers like Alfred Tarski and Donald Davidson.
The constructivist theory of meaning claims that speech is not only passively describing a given reality, but it can change the (social) reality it is describing through speech acts, which for linguistics was as revolutionary a discovery as for physics was the discovery that the very act of measurement can change the measured reality itself. Speech act theory was developed by J. L. Austin, although other previous thinkers have had similar ideas.
The reference theory of meaning, also known collectively as semantic externalism,
views meaning to be equivalent to those things in the world that are
actually connected to signs. There are two broad subspecies of
externalism: social and environmental. The first is most closely
associated with Tyler Burge and the second with Hilary Putnam, Saul Kripke and others.
The verificationist theory of meaning is generally associated with the early 20th century movement of logical positivism.
The traditional formulation of such a theory is that the meaning of a
sentence is its method of verification or falsification. In this form,
the thesis was abandoned after the acceptance by most philosophers of
the Duhem–Quine thesis of confirmation holism after the publication of Quine's "Two Dogmas of Empiricism". However, Michael Dummett has advocated a modified form of verificationism since the 1970s. In this version, the comprehension
(and hence meaning) of a sentence consists in the hearer's ability to
recognize the demonstration (mathematical, empirical or other) of the
truth of the sentence.
A pragmatic theory of meaning
is any theory in which the meaning (or understanding) of a sentence is
determined by the consequences of its application. Dummett attributes
such a theory of meaning to Charles Sanders Peirce and other early 20th century American pragmatists.
The contrast theory of meaning
suggests that knowledge attributions have a ternary structure of the
form 'S knows that p rather than q'. This is in contrast to the
traditional view whereby knowledge attributions have a binary structure
of the form 'S knows that p'.
Other theories exist to discuss non-linguistic meaning (i.e., meaning as conveyed by body language, meanings as consequences, etc.).
Reference
Investigations into how language interacts with the world are called theories of reference. Gottlob Frege was an advocate of a mediated reference theory. Frege divided the semantic content of every expression, including sentences, into two components: sense and reference.
The sense of a sentence is the thought that it expresses. Such a
thought is abstract, universal and objective. The sense of any
sub-sentential expression consists in its contribution to the thought
that its embedding sentence expresses. Senses determine reference and
are also the modes of presentation of the objects to which expressions
refer. Referents are the objects in the world that words pick out. The senses of sentences are thoughts, while their referents are truth values (true or false). The referents of sentences embedded in propositional attitude ascriptions and other opaque contexts are their usual senses.
Bertrand Russell, in his later writings and for reasons related to his theory of acquaintance in epistemology,
held that the only directly referential expressions are, what he
called, "logically proper names". Logically proper names are such terms
as I, now, here and other indexicals. He viewed proper names of the sort described above as "abbreviated definite descriptions" (see Theory of descriptions). Hence Joseph R. Biden
may be an abbreviation for "the current President of the United States
and husband of Jill Biden". Definite descriptions are denoting phrases
which are analyzed by Russell into existentially quantified logical
constructions. Such phrases denote in the sense that there is an object
that satisfies the description. However, such objects are not to be
considered meaningful on their own, but have meaning only in the proposition
expressed by the sentences of which they are a part. Hence, they are
not directly referential in the same way as logically proper names, for
Russell.
On Frege's account, any referring expression
has a sense as well as a referent. Such a "mediated reference" view has
certain theoretical advantages over Mill's view. For example,
co-referential names, such as Samuel Clemens and Mark Twain,
cause problems for a directly referential view because it is possible
for someone to hear "Mark Twain is Samuel Clemens" and be surprised –
thus, their cognitive content seems different.
Despite the differences between the views of Frege and Russell, they are generally lumped together as descriptivists about proper names. Such descriptivism was criticized in Saul Kripke's Naming and Necessity.
Kripke put forth what has come to be known as "the modal argument" (or "argument from rigidity"). Consider the name Aristotle and the descriptions "the greatest student of Plato", "the founder of logic" and "the teacher of Alexander". Aristotle obviously satisfies all of the descriptions (and many of the others we commonly associate with him), but it is not necessarily true
that if Aristotle existed then Aristotle was any one, or all, of these
descriptions. Aristotle may well have existed without doing any single
one of the things for which he is known to posterity. He may have
existed and not have become known to posterity at all or he may have
died in infancy. Suppose that Aristotle is associated by Mary with the
description "the last great philosopher of antiquity" and (the actual)
Aristotle died in infancy. Then Mary's description would seem to refer
to Plato. But this is deeply counterintuitive. Hence, names are rigid designators,
according to Kripke. That is, they refer to the same individual in
every possible world in which that individual exists. In the same work,
Kripke articulated several other arguments against "Frege–Russell" descriptivism.
The whole philosophical enterprise of studying reference has been critiqued by linguist Noam Chomsky in various works.
Social interaction and language
A
common claim is that language is governed by social conventions.
Questions inevitably arise on surrounding topics. One question is, "What
exactly is a convention, and how do we study it?", and second, "To what
extent do conventions even matter in the study of language?" David Kellogg Lewis proposed a worthy reply to the first question by expounding the view that a convention is a rationally self-perpetuating regularity in behavior.
However, this view seems to compete to some extent with the Gricean
view of speaker's meaning, requiring either one (or both) to be weakened
if both are to be taken as true.
Some have questioned whether or not conventions are relevant to the study of meaning at all. Noam Chomsky
proposed that the study of language could be done in terms of the
I-Language, or internal language of persons. If this is so, then it
undermines the pursuit of explanations in terms of conventions, and
relegates such explanations to the domain of "metasemantics".
"Metasemantics" is a term used by philosopher of language Robert
Stainton to describe all those fields that attempt to explain how
semantic facts arise.
One fruitful source of research involves investigation into the social
conditions that give rise to, or are associated with, meanings and
languages. Etymology (the study of the origins of words) and stylistics
(philosophical argumentation over what makes "good grammar", relative
to a particular language) are two other examples of fields that are
taken to be metasemantic.
Not surprisingly, many separate (but related) fields have
investigated the topic of linguistic convention within their own
research paradigms. The presumptions that prop up each theoretical view
are of interest to the philosopher of language. For instance, one of the
major fields of sociology, symbolic interactionism, is based on the insight that human social organization is based almost entirely on the use of meanings. In consequence, any explanation of a social structure (like an institution) would need to account for the shared meanings which create and sustain the structure.
Rhetoric
is the study of the particular words that people use to achieve the
proper emotional and rational effect in the listener, be it to persuade,
provoke, endear, or teach. Some relevant applications of the field
include the examination of propaganda and didacticism, the examination of the purposes of swearing and pejoratives
(especially how it influences the behavior of others, and defines
relationships), or the effects of gendered language. It can also be used
to study linguistic transparency (or speaking in an accessible manner), as well as performative
utterances and the various tasks that language can perform (called
"speech acts"). It also has applications to the study and interpretation
of law, and helps give insight to the logical concept of the domain of discourse.
Literary theory
is a discipline that some literary theorists claim overlaps with the
philosophy of language. It emphasizes the methods that readers and
critics use in understanding a text. This field, an outgrowth of the
study of how to properly interpret messages, is unsurprisingly closely
tied to the ancient discipline of hermeneutics.
Truth
Finally, philosophers of language investigate how language and meaning relate to truth and the reality being referred to. They tend to be less interested in which sentences are actually true, and more in what kinds of meanings can be true or false.
A truth-oriented philosopher of language might wonder whether or not a
meaningless sentence can be true or false, or whether or not sentences
can express propositions about things that do not exist, rather than the
way sentences are used.
The field of hermeneutics, and the theory of interpretation in
general, has played a significant role in 20th century continental
philosophy of language and ontology beginning with Martin Heidegger. Heidegger combines phenomenology with the hermeneutics of Wilhelm Dilthey. Heidegger believed language was one of the most important concepts for Dasein.
Heidegger believed that language today is worn out because of overuse
of important words, and would be inadequate for in-depth study of Being (Sein). For example, Sein (being), the word itself, is saturated with multiple meanings. Thus, he invented new vocabulary and linguistic styles, based on Ancient Greek and Germanicetymological
word relations, to disambiguate commonly used words. He avoided words
like consciousness, ego, human, nature, etc. and instead talked
holistically of Being-in-the-world, Dasein.
With such new concepts as Being-in-the-world, Heidegger constructs his theory of language, centered on speech.
He believed speech (talking, listening, silence) was the most essential
and pure form of language. Heidegger claims writing is only a
supplement to speech, because even readers construct or contribute their
own "talk" while reading. The most important feature of language is its
projectivity, the idea that language is prior to human speech.
This means that when one is "thrown" into the world, his existence is
characterized from the beginning by a certain pre-comprehension of the
world. However, only after naming, or "articulation of intelligibility",
can one have primary access to Dasein and Being-in-the-World.
Hans-Georg Gadamer expanded on these ideas of Heidegger and proposed a complete hermeneutic ontology. In Truth and Method, Gadamer describes language as "the medium in which substantive understanding and agreement take place between two people."
In addition, Gadamer claims that the world is linguistically
constituted, and cannot exist apart from language. For example,
monuments and statues cannot communicate without the aid of language.
Gadamer also claims that every language constitutes a world-view,
because the linguistic nature of the world frees each individual from an
objective environment: "... the fact that we have a world at all
depends upon [language] and presents itself in it. The world as world
exists for man as for no other creature in the world."
Paul Ricœur,
on the other hand, proposed a hermeneutics which, reconnecting with the
original Greek sense of the term, emphasized the discovery of hidden
meanings in the equivocal terms (or "symbols") of ordinary language. Other philosophers who have worked in this tradition include Luigi Pareyson and Jacques Derrida.
Semiotics
is the study of the transmission, reception and meaning of signs and
symbols in general. In this field, human language (both natural and
artificial) is just one among many ways that humans (and other conscious
beings) are able to communicate. It allows them to take advantage of
and effectively manipulate the external world in order to create meaning
for themselves and transmit this meaning to others. Every object, every
person, every event, and every force communicates (or signifies) continuously. The ringing of a telephone for example, is
the telephone. The smoke that I see on the horizon is the sign that
there is a fire. The smoke signifies. The things of the world, in this
vision, seem to be labeled precisely for intelligent beings who
only need to interpret them in the way that humans do. Everything has
meaning. True communication, including the use of human language,
however, requires someone (a sender) who sends a message, or text, in some code to someone else (a receiver).
Language is studied only insofar as it is one of these forms (the most
sophisticated form) of communication. Some important figures in the
history of semiotics, are Charles Sanders Peirce, Roland Barthes, and Roman Jakobson. In modern times, its best-known figures include Umberto Eco, A. J. Greimas, Louis Hjelmslev, and Tullio De Mauro. Investigations on signs in non-human communications are subject to biosemiotics, a field founded in the late 20th century by Thomas Sebeok and Thure von Uexküll.
Problems in the philosophy of language
Formal versus informal approaches
Another
of the questions that has divided philosophers of language is the
extent to which formal logic can be used as an effective tool in the
analysis and understanding of natural languages. While most
philosophers, including Gottlob Frege, Alfred Tarski and Rudolf Carnap,
have been more or less skeptical about formalizing natural languages,
many of them developed formal languages for use in the sciences or
formalized parts of natural language for investigation. Some of the most prominent members of this tradition of formal semantics include Tarski, Carnap, Richard Montague and Donald Davidson.
On the other side of the divide, and especially prominent in the 1950s and '60s, were the so-called "ordinary language philosophers". Philosophers such as P. F. Strawson, John Langshaw Austin and Gilbert Ryle
stressed the importance of studying natural language without regard to
the truth-conditions of sentences and the references of terms. They did
not believe that the social and practical dimensions of linguistic
meaning could be captured by any attempts at formalization using the
tools of logic. Logic is one thing and language is something entirely
different. What is important is not expressions themselves but what
people use them to do in communication.
Hence, Austin developed a theory of speech acts,
which described the kinds of things which can be done with a sentence
(assertion, command, inquiry, exclamation) in different contexts of use
on different occasions. Strawson argued that the truth-table semantics of the logical connectives (e.g., , and ) do not capture the meanings of their natural language counterparts ("and", "or" and "if-then").
While the "ordinary language" movement basically died out in the 1970s,
its influence was crucial to the development of the fields of
speech-act theory and the study of pragmatics. Many of its ideas have been absorbed by theorists such as Kent Bach, Robert Brandom, Paul Horwich and Stephen Neale.
In recent work, the division between semantics and pragmatics has
become a lively topic of discussion at the interface of philosophy and
linguistics, for instance in work by Sperber and Wilson, Carston and
Levinson.
While keeping these traditions in mind, the question of whether
or not there is any grounds for conflict between the formal and informal
approaches is far from being decided. Some theorists, like Paul Grice, have been skeptical of any claims that there is a substantial conflict between logic and natural language.
Problem of universals and composition
One debate that has captured the interest of many philosophers is the debate over the meaning of universals. One might ask, for example, "When people say the word rocks,
what is it that the word represents?" Two different answers have
emerged to this question. Some have said that the expression stands for
some real, abstract universal out in the world called "rocks". Others
have said that the word stands for some collection of particular,
individual rocks that we associate with merely a nomenclature. The
former position has been called philosophical realism, and the latter nominalism.
The issue here can be explicated if we examine the proposition "Socrates is a Man".
From the realist's perspective, the connection between S and M is
a connection between two abstract entities. There is an entity, "man",
and an entity, "Socrates". These two things connect in some way or
overlap.
From a nominalist's perspective, the connection between S and M
is the connection between a particular entity (Socrates) and a vast
collection of particular things (men). To say that Socrates is a man is
to say that Socrates is a part of the class of "men". Another
perspective is to consider "man" to be a property of the entity, "Socrates".
There is a third way, between nominalism and (extreme) realism, usually called "moderate realism"
and attributed to Aristotle and Thomas Aquinas. Moderate realists hold
that "man" refers to a real essence or form that is really present and
identical in Socrates and all other men, but "man" does not exist as a
separate and distinct entity. This is a realist position, because "Man"
is real, insofar as it really exists in all men; but it is a moderate
realism, because "Man" is not an entity separate from the men it
informs.
Age of Enlightenment philosopher Antoine Arnauld
argued that people had created language rationally in a step-by-step
process to fulfill a psychological need to communicate with others. 19th century romanticism emphasised human agency and free will in meaning construction. More lately, Eugenio Coșeriu underlined the role of intention in the processes, while others including Esa Itkonen believe that the social construction of language takes place unconsciously. In Saussure's notion, language is a social fact which arises from social interaction,
but can neither be reduced to the individual acts nor to human
psychology, which supports the autonomy of the study of language from
other sciences.
Translation and interpretation are two other problems that philosophers of language have attempted to confront. In the 1950s, W.V. Quine argued for the indeterminacy of meaning and reference based on the principle of radical translation. In Word and Object,
Quine asks readers to imagine a situation in which they are confronted
with a previously undocumented, group of indigenous people where they
must attempt to make sense of the utterances and gestures that its
members make. This is the situation of radical translation.
He claimed that, in such a situation, it is impossible in principle
to be absolutely certain of the meaning or reference that a speaker of
the indigenous peoples language attaches to an utterance. For example,
if a speaker sees a rabbit and says "gavagai", is she referring to the
whole rabbit, to the rabbit's tail, or to a temporal part of the rabbit.
All that can be done is to examine the utterance as a part of the
overall linguistic behaviour of the individual, and then use these
observations to interpret the meaning of all other utterances. From this
basis, one can form a manual of translation. But, since reference is
indeterminate, there will be many such manuals, no one of which is more
correct than the others. For Quine, as for Wittgenstein and Austin,
meaning is not something that is associated with a single word or
sentence, but is rather something that, if it can be attributed at all,
can only be attributed to a whole language. The resulting view is called semantic holism.
Inspired by Quine's discussion, Donald Davidson
extended the idea of radical translation to the interpretation of
utterances and behavior within a single linguistic community. He dubbed
this notion radical interpretation. He suggested that the meaning
that any individual ascribed to a sentence could only be determined by
attributing meanings to many, perhaps all, of the individual's
assertions, as well as their mental states and attitudes.
Vagueness
One issue that has troubled philosophers of language and logic is the problem of the vagueness
of words. The specific instances of vagueness that most interest
philosophers of language are those where the existence of "borderline
cases" makes it seemingly impossible to say whether a predicate is true
or false. Classic examples are "is tall" or "is bald", where it cannot
be said that some borderline case (some given person) is tall or
not-tall. In consequence, vagueness gives rise to the paradox of the heap. Many theorists have attempted to solve the paradox by way of n-valued logics, such as fuzzy logic, which have radically departed from classical two-valued logics.
"From each according to his ability, to each according to his needs" (German: Jeder nach seinen Fähigkeiten, jedem nach seinen Bedürfnissen) is a slogan popularised by Karl Marx in his 1875 Critique of the Gotha Program. The principle refers to free access to and distribution of goods, capital and services. In the Marxist view, such an arrangement will be made possible by the abundance of goods and services that a developed communist system will be capable to produce; the idea is that, with the full development of socialism and unfettered productive forces, there will be enough to satisfy everyone's needs.
Origin of the phrase
The complete paragraph containing Marx's statement of the creed in the Critique of the Gotha Program is as follows:
In
a higher phase of communist society, after the enslaving subordination
of the individual to the division of labor, and therewith also the
antithesis between mental and physical labor, has vanished; after labor
has become not only a means of life but life's prime want; after the
productive forces have also increased with the all-around development of
the individual, and all the springs of co-operative wealth flow more
abundantly—only then can the narrow horizon of bourgeois right be
crossed in its entirety and society inscribe on its banners: From each according to his ability, to each according to his needs!
Although Marx is popularly thought of as the originator of the
phrase, the slogan was common within the socialist movement. For
example, August Becker in 1844 described it as the basic principle of communism and Louis Blanc used it in 1851. The French socialist Saint-Simonists
of the 1820s and 1830s used slightly different slogans such as," from
each according to his ability, to each ability according to its work" or," From each according to his capacity, to each according to his works.” The origin of this phrasing has also been attributed to the French utopian Étienne-Gabriel Morelly, who proposed in his 1755 Code of Nature "Sacred and Fundamental Laws that would tear out the roots of vice and of all the evils of a society", including:
I.
Nothing in society will belong to anyone, either as a personal
possession or as capital goods, except the things for which the person
has immediate use, for either his needs, his pleasures, or his daily
work. II. Every citizen will be a public man, sustained by, supported by, and occupied at the public expense. III.
Every citizen will make his particular contribution to the activities
of the community according to his capacity, his talent and his age; it
is on this basis that his duties will be determined, in conformity with
the distributive laws.
We
whose names are here underwritten, intending by God's gracious
permission to plant ourselves in New England, and if it may be, in the
southerly part about Quinnipiack, do faithfully promise each, for
ourselves and our families and those that belong to us, that we will,
the Lord assisting us, sit down and join ourselves together in one
entire plantation, and be helpful each to the other in any common work, according to every man's ability, and as need shall require,
and we promise not to desert or leave each other or the plantation, but
with the consent of the rest, or the greater part of the company who
have entered into this engagement.
Some scholars trace the phrase to the New Testament. In Acts of the Apostles
the lifestyle of the community of believers in Jerusalem is described
as communal (without individual possession), and uses the phrase "distribution was made unto every man according as he had need" (διεδίδετο δὲ ἑκάστῳ καθότι ἄν τις χρείαν εἶχεν):
Acts
4:32–35: ³² And the multitude of them that believed were of one heart
and of one soul: neither said any of them that ought of the things which
he possessed was his own; but they had all things common. ³³ And with
great power gave the apostles witness of the resurrection of the Lord
Jesus: and great grace was upon them all. ³⁴ Neither was there any among
them that lacked: for as many as were possessors of lands or houses
sold them, and brought the prices of the things that were sold, ³⁵ And
laid them down at the apostles' feet: and distribution was made unto
every man according as he had need.
Other scholars find its origins in "the Roman legal concept of obligation in solidum",
in which "everyone assumes responsibility for anyone who cannot pay his
debt, and he is conversely responsible for everyone else". James Furner argues:
If x = a disadvantage, and y = action to redress that disadvantage,
the principle of solidarity is: if any member of a group acquires x,
each member has a duty to perform y (if they can assist). All we then
need to add, to get to the fundamental principle of developed communism,
is to assume that non-satisfaction of a need is a disadvantage. The
corresponding principle of solidarity in respect of need says: if any
member of society has an unsatisfied need, each member has a duty to
produce its object (if they can). But that is precisely what the
principle 'from each according to their abilities, to each according to
their needs!' dictates. In Marx's vision, the basic principle of
developed communism is a principle of solidarity in respect of need.
Debates on the idea
Marx
delineated the specific conditions under which such a creed would be
applicable—a society where technology and social organization had
substantially eliminated the need for physical labor in the production
of things, where "labor has become not only a means of life but life's
prime want".
Marx explained his belief that, in such a society, each person would be
motivated to work for the good of society despite the absence of a
social mechanism compelling them to work, because work would have
become a pleasurable and creative activity. Marx intended the initial
part of his slogan, "from each according to his ability" to suggest not
merely that each person should work as hard as they can, but that each
person should best develop their particular talents.
Claiming themselves to be at a "lower stage of communism" (i.e. "socialism", in line with Vladimir Lenin’s terminology), the Soviet Union adapted the formula as: "From each according to his ability, to each according to his work (labour investment)". This was incorporated in Article 12 of the 1936 Constitution of the Soviet Union, but described by Leon Trotsky as "This inwardly contradictory, not to say nonsensical, formula".
While liberation theology
has sought to interpret the Christian call for justice in a way that is
in harmony with this Marxist dictum, many have noted that Jesus'
teaching in the Parable of the Talents (Matthew 25:14–30) affirms only "TO each according to his ability" (Matt. 25:15), and not "FROM each according to his ability".
In popular culture
In Ayn Rand's 1957 novel Atlas Shrugged,
a large and profitable motor company adopted this slogan as its method
for determining employee compensation. The system quickly fell prey to
corruption and greed, forcing the most capable employees to work
overtime in order to satisfy the needs of the least competent and to
funnel money to the owners. As a result, the company went bankrupt
within four years.
In Margaret Atwood's 1985 novel The Handmaid's Tale, members of a dystopian society recited the phrase thrice daily.
Notably the phrase is altered to read "From each according to her
ability; to each according to his need", demonstrating a perversion of
the phrase's original intention by Atwood's fictional society.
In Vladimir Voinovich's 1986 novel Moscow 2042, the slogan was parodied in the context of "communism in one city". Every morning the radio announced: "Comrades, your needs for today are as follows: ...".
"According to Need" is a 5-part documentary from the podcast 99% Invisible. It focuses on the homeless and what America is doing (and Oakland, California, in particular is doing) to find them housing.
