A simple negative feedback system is descriptive, for example, of some electronic amplifiers. The feedback is negative if the loop gain AB is negative.
Negative feedback (or balancing feedback) occurs when some function of the output of a system, process, or mechanism is fed back
in a manner that tends to reduce the fluctuations in the output,
whether caused by changes in the input or by other disturbances.
Whereas positive feedback tends to instability via exponential growth, oscillation or chaotic behavior, negative feedback generally promotes stability. Negative feedback tends to promote a settling to equilibrium, and reduces the effects of perturbations. Negative feedback loops in which just the right amount of correction is applied with optimum timing, can be very stable, accurate, and responsive.
Negative feedback is widely used in mechanical and electronic engineering, and it is observed in many other fields including biology, chemistry and economics. General negative feedback systems are studied in control systems engineering.
Negative feedback loops also play an integral role in maintaining
the atmospheric balance in various climate systems on Earth. One such
feedback system is the interaction between solar radiation, cloud cover, and planet temperature.
Blood
glucose levels are maintained at a constant level in the body by a
negative feedback mechanism. When the blood glucose level is too high,
the pancreas secretes insulin and when the level is too low, the
pancreas then secretes glucagon. The flat line shown represents the
homeostatic set point. The sinusoidal line represents the blood glucose
level.
General description
Feedback loops in the human body
In many physical and biological systems, qualitatively different
influences can oppose each other. For example, in biochemistry, one set
of chemicals drives the system in a given direction, whereas another set
of chemicals drives it in an opposing direction. If one or both of
these opposing influences are non-linear, equilibrium point(s) result.
In engineering, mathematics and the physical, and biological sciences, common terms for the points around which the system gravitates include: attractors, stable states, eigenstates/eigenfunctions, equilibrium points, and setpoints.
In control theory, negative
refers to the sign of the multiplier in mathematical models for
feedback. In delta notation, −Δoutput is added to or mixed into the
input. In multivariate systems, vectors help to illustrate how several
influences can both partially complement and partially oppose each
other.
Some authors, in particular with respect to modelling business systems, use negative to refer to the reduction in difference between the desired and actual behavior of a system. In a psychology context, on the other hand, negative refers to the valence of the feedback – attractive versus aversive, or praise versus criticism.
In contrast, positive feedback
is feedback in which the system responds so as to increase the
magnitude of any particular perturbation, resulting in amplification of
the original signal instead of stabilization. Any system in which there
is positive feedback together with a gain greater than one will result
in a runaway situation. Both positive and negative feedback require a
feedback loop to operate.
However, negative feedback systems can still be subject to oscillations.
This is caused by a phase shift around any loop. Due to these phase
shifts the feedback signal of some frequencies can ultimately become in
phase with the input signal and thus turn into positive feedback,
creating a runaway condition. Even before the point where the phase
shift becomes 180 degrees, stability of the negative feedback loop will
become compromised, leading to increasing under- and overshoot following
a disturbance. This problem is often dealt with by attenuating or
changing the phase of the problematic frequencies in a design step
called compensation. Unless the system naturally has sufficient damping,
many negative feedback systems have low pass filters or dampers fitted.
Examples
Mercury thermostats
(circa 1600) using expansion and contraction of columns of mercury in
response to temperature changes were used in negative feedback systems
to control vents in furnaces, maintaining a steady internal temperature.
In centrifugal governors
(1788), negative feedback is used to maintain a near-constant speed of
an engine, irrespective of the load or fuel-supply conditions.
In a steering engine (1866), power assistance is applied to the rudder with a feedback loop, to maintain the direction set by the steersman.
In servomechanisms, the speed or position of an output, as determined by a sensor, is compared to a set value, and any error is reduced by negative feedback to the input.
In audioamplifiers, negative feedback flattens frequency response, reduces distortion,
minimises the effect of manufacturing variations in component
parameters, and compensates for changes in characteristics due to
temperature change.
In a phase locked loop (1932), feedback is used to maintain a generated alternating waveform in a constant phase to a reference signal. In many implementations the generated waveform is the output, but when used as a demodulator in an FM radio receiver, the error feedback voltage serves as the demodulated output signal. If there is a frequency divider between the generated waveform and the phase comparator, the device acts as a frequency multiplier.
In organisms, feedback enables various measures (e.g. body temperature, or blood sugar level) to be maintained within a desired range by homeostatic processes.
A regulator R adjusts the input to a system T so the monitored essential variables E are held to set-point values S that result in the desired system output despite disturbances D.
One use of feedback is to make a system (say T) self-regulating to minimize the effect of a disturbance (say D). Using a negative feedback loop, a measurement of some variable (for example, a process variable, say E) is subtracted from a required value (the 'set point') to estimate an operational error in system status, which is then used by a regulator (say R) to reduce the gap between the measurement and the required value. The regulator modifies the input to the system T
according to its interpretation of the error in the status of the
system. This error may be introduced by a variety of possible
disturbances or 'upsets', some slow and some rapid. The regulation in such systems can range from a simple 'on-off' control to a more complex processing of the error signal.
In this framework, the physical form of a signal may undergo
multiple transformations. For example, a change in weather may cause a
disturbance to the heat input to a house (as an example of the system T) that is monitored by a thermometer as a change in temperature (as an example of an 'essential variable' E). This quantity, then, is converted by the thermostat (a 'comparator') into an electrical error in status compared to the 'set point' S, and subsequently used by the regulator (containing a 'controller' that commands gas control valves and an ignitor) ultimately to change the heat provided by a furnace (an 'effector') to counter the initial weather-related disturbance in heat input to the house.
Error controlled regulation is typically carried out using a Proportional-Integral-Derivative Controller (PID controller).
The regulator signal is derived from a weighted sum of the error
signal, integral of the error signal, and derivative of the error
signal. The weights of the respective components depend on the
application.
The negative feedback amplifier was invented by Harold Stephen Black at Bell Laboratories in 1927, and granted a patent in 1937 (US Patent 2,102,671) "a continuation of application Serial No. 298,155, filed August 8, 1928 ...").
"The patent is 52 pages long plus 35 pages of figures. The first 43 pages amount to a small treatise on feedback amplifiers!"
There are many advantages to feedback in amplifiers. In design, the type of feedback and amount of feedback are carefully selected to weigh and optimize these various benefits.
Advantages of amplifier negative voltage feedback
Negative voltage feedback in amplifiers has the following advantages; it
The feedback sets the overall (closed-loop) amplifier gain at a value:
where the approximate value assumes βA >> 1. This
expression shows that a gain greater than one requires β < 1. Because
the approximate gain 1/β is independent of the open-loop gain A, the feedback is said to 'desensitize' the closed-loop gain to variations in A
(for example, due to manufacturing variations between units, or
temperature effects upon components), provided only that the gain A is sufficiently large. In this context, the factor (1+βA) is often called the 'desensitivity factor', and in the broader context of feedback effects that include other matters like electrical impedance and bandwidth, the 'improvement factor'.
If the disturbance D is included, the amplifier output becomes:
which shows that the feedback reduces the effect of the disturbance by the 'improvement factor' (1+β A). The disturbance D
might arise from fluctuations in the amplifier output due to noise and
nonlinearity (distortion) within this amplifier, or from other noise
sources such as power supplies.
The difference signal I–βO at the amplifier input is sometimes called the "error signal". According to the diagram, the error signal is:
From this expression, it can be seen that a large 'improvement factor' (or a large loop gain βA) tends to keep this error signal small.
Although the diagram illustrates the principles of the negative feedback amplifier, modeling a real amplifier as a unilateral forward amplification block and a unilateral feedback block has significant limitations. For methods of analysis that do not make these idealizations, see the article Negative feedback amplifier.
A feedback voltage amplifier using an op amp with finite gain but infinite input impedances and zero output impedance.
The operational amplifier was originally developed as a building block for the construction of analog computers, but is now used almost universally in all kinds of applications including audio equipment and control systems.
Operational amplifier circuits typically employ negative feedback
to get a predictable transfer function. Since the open-loop gain of an op-amp
is extremely large, a small differential input signal would drive the
output of the amplifier to one rail or the other in the absence of
negative feedback. A simple example of the use of feedback is the op-amp
voltage amplifier shown in the figure.
The idealized model of an operational amplifier assumes that the
gain is infinite, the input impedance is infinite, output resistance is
zero, and input offset currents and voltages are zero. Such an ideal
amplifier draws no current from the resistor divider. Ignoring dynamics (transient effects and propagation delay),
the infinite gain of the ideal op-amp means this feedback circuit
drives the voltage difference between the two op-amp inputs to zero. Consequently, the voltage gain of the circuit in the diagram, assuming an ideal op amp, is the reciprocal of feedback voltage division ratio β:
.
A real op-amp has a high but finite gain A at low frequencies,
decreasing gradually at higher frequencies. In addition, it exhibits a
finite input impedance and a non-zero output impedance. Although
practical op-amps are not ideal, the model of an ideal op-amp often
suffices to understand circuit operation at low enough frequencies.
As discussed in the previous section, the feedback circuit stabilizes
the closed-loop gain and desensitizes the output to fluctuations
generated inside the amplifier itself.
Control of endocrine hormones by negative feedback.
Some biological systems exhibit negative feedback such as the baroreflex in blood pressure regulation and erythropoiesis. Many biological processes (e.g., in the human anatomy) use negative feedback. Examples of this are numerous, from the regulating of body temperature, to the regulating of blood glucose levels. The disruption of feedback loops can lead to undesirable results: in the case of blood glucose levels, if negative feedback fails, the glucose levels in the blood may begin to rise dramatically, thus resulting in diabetes.
For hormone secretion regulated by the negative feedback loop:
when gland X releases hormone X, this stimulates target cells to release
hormone Y. When there is an excess of hormone Y, gland X "senses" this
and inhibits its release of hormone X. As shown in the figure, most endocrinehormones are controlled by a physiologic negative feedback inhibition loop, such as the glucocorticoids secreted by the adrenal cortex. The hypothalamus secretes corticotropin-releasing hormone (CRH), which directs the anterior pituitary gland to secrete adrenocorticotropic hormone (ACTH). In turn, ACTH directs the adrenal cortex to secrete glucocorticoids, such as cortisol.
Glucocorticoids not only perform their respective functions throughout
the body but also negatively affect the release of further stimulating
secretions of both the hypothalamus and the pituitary gland, effectively
reducing the output of glucocorticoids once a sufficient amount has
been released.
Chemistry
Closed systems containing substances undergoing a reversible chemical reaction can also exhibit negative feedback in accordance with Le Chatelier's principle which shift the chemical equilibrium to the opposite side of the reaction in order to reduce a stress. For example, in the reaction
N2 + 3 H2 ⇌ 2 NH3 + 92 kJ/mol
If a mixture of the reactants and products exists at equilibrium in a
sealed container and nitrogen gas is added to this system, then the
equilibrium will shift toward the product side in response. If the
temperature is raised, then the equilibrium will shift toward the
reactant side which, since the reverse reaction is endothermic, will
partially reduce the temperature.
Self-organization is the capability of certain systems "of organizing their own behavior or structure". There are many possible factors contributing to this capacity, and most often positive feedback is identified as a possible contributor. However, negative feedback also can play a role.
Economics
In economics, automatic stabilisers are government programs that are intended to work as negative feedback to dampen fluctuations in real GDP.
Mainstream economics asserts that the market pricing mechanism operates to match supply and demand,
because mismatches between them feed back into the decision-making of
suppliers and demanders of goods, altering prices and thereby reducing
any discrepancy. However Norbert Wiener wrote in 1948:
"There is a belief current in many countries and elevated to
the rank of an official article of faith in the United States that free
competition is itself a homeostatic process... Unfortunately the
evidence, such as it is, is against this simple-minded theory."
A basic and common example of a negative feedback system in the environment is the interaction among cloud cover, plant growth, solar radiation, and planet temperature. As incoming solar radiation increases, planet temperature increases. As
the temperature increases, the amount of plant life that can grow
increases. This plant life can then make products such as sulfur which
produce more cloud cover. An increase in cloud cover leads to higher albedo, or surface reflectivity, of the Earth. As albedo increases, however, the amount of solar radiation decreases. This, in turn, affects the rest of the cycle.
Cloud cover, and in turn planet albedo and temperature, is also influenced by the hydrological cycle. As planet temperature increases, more water vapor is produced, creating more clouds. The clouds then block incoming solar radiation, lowering the temperature of the planet. This interaction produces less water vapor
and therefore less cloud cover. The cycle then repeats in a negative
feedback loop. In this way, negative feedback loops in the environment
have a stabilizing effect.
History
Negative feedback as a control technique may be seen in the refinements of the water clock introduced by Ktesibios
of Alexandria in the 3rd century BCE. Self-regulating mechanisms have
existed since antiquity, and were used to maintain a constant level in
the reservoirs of water clocks as early as 200 BCE.
Negative feedback was implemented in the 17th century. Cornelius Drebbel had built thermostatically controlled incubators and ovens in the early 1600s, and centrifugal governors were used to regulate the distance and pressure between millstones in windmills. James Watt patented a form of governor in 1788 to control the speed of his steam engine, and James Clerk Maxwell
in 1868 described "component motions" associated with these governors
that lead to a decrease in a disturbance or the amplitude of an
oscillation.
The term "feedback" was well established by the 1920s, in reference to a means of boosting the gain of an electronic amplifier. Friis and Jensen described this action as "positive feedback" and made
passing mention of a contrasting "negative feed-back action" in 1924. Harold Stephen Black came up with the idea of using negative feedback in electronic amplifiers in 1927, submitted a patent application in 1928, and detailed its use in his paper of 1934, where he defined negative feedback as a type of coupling that reduced the gain of the amplifier, in the process greatly increasing its stability and bandwidth.
Nyquist and Bode built on Black's work to develop a theory of amplifier stability.
Early researchers in the area of cybernetics subsequently generalized the idea of negative feedback to cover any goal-seeking or purposeful behavior.
All purposeful behavior may be
considered to require negative feed-back. If a goal is to be attained,
some signals from the goal are necessary at some time to direct the
behavior.
Cybernetics pioneer Norbert Wiener
helped to formalize the concepts of feedback control, defining feedback
in general as "the chain of the transmission and return of
information", and negative feedback as the case when:
The information fed back to the control center tends to oppose the departure of the controlled from the controlling quantity...: 97
While the view of feedback as any "circularity of action" helped to keep the theory simple and consistent, Ashby
pointed out that, while it may clash with definitions that require a
"materially evident" connection, "the exact definition of feedback is
nowhere important". Ashby pointed out the limitations of the concept of "feedback":
The concept of 'feedback', so
simple and natural in certain elementary cases, becomes artificial and
of little use when the interconnections between the parts become more
complex...Such complex systems cannot be treated as an interlaced set of
more or less independent feedback circuits, but only as a whole. For
understanding the general principles of dynamic systems, therefore, the
concept of feedback is inadequate in itself. What is important is that
complex systems, richly cross-connected internally, have complex
behaviors, and that these behaviors can be goal-seeking in complex
patterns.: 54
To reduce confusion, later authors have suggested alternative terms such as degenerative, self-correcting, balancing, or discrepancy-reducing in place of "negative".
The history of social democracy stretches back to the 19th-century labour movement. Originally a catch-all term for socialists of varying tendencies, after the Russian Revolution, it came to refer to reformist socialists who were strategically opposed to revolution as well as the authoritarianism of the Soviet model, nonetheless the eventual abolition of capitalism was still being upheld as an important end goal during this time. However, by the 1990s social democrats had embraced mixed economies with a predominance of private property and promoted the regulation of capitalism over its replacement with a qualitatively different socialist economic system. Since that time, social democracy has been associated with Keynesian economics, the Nordic model, and welfare states.
Social democracy has been described as the most common form of Western or modern socialism,as well as the reformist wing of democratic socialism. Amongst social democrats, attitudes towards socialism vary: some retain
socialism as a long-term goal, with social democracy being a political and economic democracy supporting a gradualist, reformist, and democratic approach towards achieving socialism. Others view it as an ethical ideal
to guide reforms within capitalism. While both social democracy and
democratic socialism once referred to movements seeking to achieve
socialism, modern social democracies retain a capitalist system, whereas
democratic socialists continue to advocate for its abolition. Nevertheless, the distinction remains blurred in colloquial settings, and the two terms are commonly used synonymously.
The Third Way is an offshoot of social democracy which aims to fuse economic liberalism with social democratic economic policies and center-left
social policies. It is a reconceptualization of social democracy
developed in the 1990s and is embraced by some social democratic
parties; with some political scientists and analysts characterising the
Third Way as an effectively neoliberal movement.
Definitions
As a tradition of socialism
Social democracy is defined as one of many socialist traditions. As an international political movement and ideology, it aims to achieve socialism through gradual and democratic means. This definition goes back to the influence of both the reformist socialism of Ferdinand Lassalle and the internationalistrevolutionary socialism advanced by Karl Marx and Friedrich Engels. Social democracy has undergone various major forms throughout its history. In the 19th century, it encompassed various non-revolutionary and revolutionary currents of socialism, excluding anarchism. In one of the first scholarly works on European socialism written for an American audience, Richard T. Ely's 1883 book French and German Socialism in Modern Times,
social democrats were characterized as "the extreme wing of the
socialists" who were "inclined to lay so much stress on equality of
enjoyment, regardless of the value of one's labor, that they might,
perhaps, more properly be called communists". In the early 20th century, social democracy came to refer to support
for a process of developing society through existing political
structures and opposition to revolutionary means, which are often
associated with Marxism. Thus whereas in the 19th century, social democracy could be described
as "organized Marxism", it became "organized reformism" by the 20th
century.
In political science, democratic socialism and social democracy are sometimes seen as synonyms, while they are distinguished in journalistic use. Under this democratic socialist definition, social democracy is an ideology seeking to gradually build an alternative socialist economy through the institutions of liberal democracy. Starting in the post-war period, social democracy was defined as a
policy regime advocating the reformation of capitalism to align it with
the ethical ideals of social justice.
What socialists such as anarchists, communists, social democrats, syndicalists, and some social democratic proponents of the Third Way share in common is history, specifically that they can all be traced back to the individuals, groups, and literature of the First International, and have retained some of the terminology and symbolism such as the colour red.
How far society should intervene and whether the government, mainly the
existing government, is the right vehicle for change are issues of
disagreement. As the Historical Dictionary of Socialism
summarizes, "there were general criticisms about the social effects of
the private ownership and control of capital", "a general view that the
solution to these problems lay in some form of collective control (with
the degree of control varying among the proponents of socialism) over
the means of production, distribution, and exchange", and "there was
agreement that the outcomes of this collective control should be a
society that provided social equality and justice, economic protection,
and generally a more satisfying life for most people". Socialism became a catch-all term for the critics of capitalism and industrial society. Social democrats are anticapitalists
insofar as criticism about "poverty, low wages, unemployment, economic
and social inequality, and a lack of economic security" is linked to the
private ownership of the means of production.
Social democracy or social democratic remains controversial among socialists.Some define it as representing a Marxist faction and non-communist socialists or the right-wing of socialism during the split with communism. Others have noted its pejorative use among communists and other socialists. According to Lyman Tower Sargent, "socialism refers to social theories rather than to theories oriented to the individual. Because many communists now call themselves democratic socialists, it is sometimes difficult to know what a political label really means. As a result, social democratic has become a common new label for democratic socialist political parties."
As a policy regime
As a policy regime, social democracy entails support for a mixed economy and ameliorative measures to benefit the working class within the framework of democratic capitalism. Social democracy currently depicts a chiefly capitalist economy with
state economic regulation in the general interest, state provision of
welfare services and state redistribution of income and wealth. Social
democratic concepts influence the policies of most Western states since
World War 2. Social democracy is frequently considered a practical middle course
between capitalism and socialism. Social democracy aims to use
democratic collective action for promoting freedom and equality in the
economy and opposes what is seen as inequality and oppression that
laissez-faire capitalism causes.
In the 21st century, it has become commonplace to define social
democracy in reference to Northern and Western European countries, and their model of a welfare state with a corporatist system of collective bargaining. Social democracy has also been used synonymously with the Nordic model. Henning Meyer and Jonathan Rutherford associate social democracy with
the socioeconomic order in Europe from the post-war period until the
early 1990s. Social democratic roots are also observed in Latin America during the
early 20th century; this was the case in Uruguay during the two
presidential terms of José Batlle y Ordóñez.
While the welfare state has been accepted across the political spectrum, particularly by conservatives (Christian democrats) and liberals (social liberals), one notable difference is that socialists see the welfare state "not
merely to provide benefits but to build the foundation for emancipation
and self-determination". In the 21st century, a social democratic policy regime may further be distinguished by a support for an increase in welfare policies or an increase in public services.
Some distinguish between ideological social democracy as part of
the broad socialist movement and social democracy as a policy regime.
They call the first classical social democracy or classical socialism, and the latter as competitive socialism, liberal socialism, neo-social democracy, or new social democracy.
The Third Way is sometimes regarded as an effort to combine social democratic values with economic liberalism,
embraced most notably by Bill Clinton's New Democrats and Tony Blair's
New Labour. Some analysts have characterized the Third Way neoliberal rather than social democratic.
In the 20th century, the term came to be associated with the positions of the German and Swedish parties. The first advocated revisionist Marxism, while the second advocated a comprehensive welfare state. By the 21st century, parties advocating social democracy include Labour, Left, and some Green parties. Most social democratic parties consider themselves democratic socialists and are categorized as socialists. They continue to reference socialism, either as a post-capitalist order or, in more ethical terms, as a just society, described as representing democratic socialism, without any explicit reference to the economic system or its structure. Parties such as the Social Democratic Party of Germany and the Swedish Social Democratic Party describe their goal as developing democratic socialism, with social democracy as the principle of action. In the 21st century, European social democratic parties represent the centre-left and most are part of the Party of European Socialists, while democratic socialist parties are to their left within the Party of the European Left. Many of those social democratic parties are members of the Socialist International, including several democratic socialist parties, whose Frankfurt Declaration declares the goal of developing democratic socialism. Others are also part of the Progressive Alliance, founded in 2013 by most contemporary or former member parties of the Socialist International.
As Marxist revisionism
Social democracy has been seen as a revision of Marxism, although this has been described as misleading for modern social democracy. Marxist revisionistEduard Bernstein's views influenced and laid the groundwork for developing post-war social democracy as a policy regime, Labour revisionism, and the neo-revisionism of the Third Way. This definition of social democracy is focused on ethical terms, with the type of socialism advocated being ethical and liberal. Bernstein described socialism and social democracy in particular as organized liberalism; in this sense, liberalism is the predecessor and precursor of socialism, whose restricted view of freedom is to be socialized, while democracy must entail social democracy. For those social democrats, who still describe and see themselves as socialists, socialism is used in ethical or moral terms, representing democracy, egalitarianism, and social justice rather than a specifically socialist economic system. Under this type of definition, social democracy's goal is that of advancing those values within a capitalist market economy, as its support for a mixed economy no longer denotes the coexistence between private and public ownership or that between planning and market mechanisms but rather, it represents free markets combined with government intervention and regulations.
Philosophy
As a form of reformist democratic socialism, social democracy rejects the either/or interpretation of capitalism versus socialism. It claims that fostering a progressive evolution of capitalism will
gradually result in the evolution of a capitalist economy into a
socialist economy. All citizens should be legally entitled to certain social rights:
universal access to public services such as education, health care,
workers' compensation, and other services, including child care and care
for the elderly. Social democrats advocate freedom from discrimination based on differences in ability/disability, age, ethnicity, gender, language, race, religion, sexual orientation, and social class.
A portrait highlighting the five leaders of early social democracy in Germany
Later in their lives, Karl Marx and Friedrich Engels argued that in some countries, workers might be able to achieve their aims through peaceful means. In this sense, Engels argued that socialists were evolutionists, although both Marx and Engels remained committed to social revolution. In developing social democracy, Eduard Bernstein rejected orthodox Marxism's revolutionary and materialist foundations. Rather than class conflict and socialist revolution, Bernstein's Marxist revisionism reflected that socialism could be achieved through cooperation between people regardless of class. Nonetheless, Bernstein paid deference to Marx, describing him as the
father of social democracy but declaring that it was necessary to revise
Marx's thought in light of changing conditions. Influenced by the gradualist platform favoured by the Fabian movement in Britain, Bernstein advocated a similar evolutionary approach to socialist politics that he termed evolutionary socialism. Evolutionary means include representative democracy
and cooperation between people regardless of class. Bernstein accepted
the Marxist analysis that the creation of socialism is interconnected
with the evolution of capitalism.
August Bebel, Bernstein, Engels, Wilhelm Liebknecht, Marx, and Carl Wilhelm Tölcke
are all considered founders of social democracy in Germany. However,
Bernstein and Lassalle, along with labourists and reformists such as Louis Blanc in France, led to the widespread association of social democracy with socialist reformism. While Lassalle was a reformist state socialist, Bernstein predicted a long-term coexistence of democracy with a mixed economy during the reforming of capitalism into socialism and argued that socialists needed to accept this. This mixed economy would involve public, cooperative, and private enterprises,
and it would be necessary for an extended period before private
enterprises evolve of their own accord into cooperative enterprises. Bernstein supported state ownership only for certain parts of the
economy that the state could best manage and rejected a mass scale of
state ownership as being too burdensome to be manageable. Bernstein was an advocate of Kantian socialism and neo-Kantianism. Although unpopular early on, his views became mainstream after World War I.
Anthony Crosland,
who argued that traditional capitalism had been reformed and modified
almost out of existence by the social democratic welfare policy regime
after World War II
In The Future of Socialism (1956), Anthony Crosland
argued that "traditional capitalism has been reformed and modified
almost out of existence, and it is with a quite different form of
society that socialists must now concern themselves. Pre-war
anti-capitalism will give us very little help", for a new kind of
capitalism required a new kind of socialism. Crosland believed that
these features of reformed managerial capitalism were irreversible, but
it has been argued within the Labour Party and by others that Margaret Thatcher and Ronald Reagan
brought about its reversal in the 1970s and 1980s. Although the
post-war consensus represented a period where social democracy was "most
buoyant", it has been argued that "post-war social democracy had been
altogether too confident in its analysis" because "gains which were
thought to be permanent turned out to be conditional and as the
reservoir of capitalist growth showed signs of drying up". In Socialism Now
(1974), Crosland argued that "[m]uch more should have been achieved by a
Labour Government in office and Labour pressure in opposition. Against
the dogged resistance to change, we should have pitted a stronger will
to change. I conclude that a move to the Left is needed".
In Origin, Ideology and Transformation of Political Parties: East-Central and Western Europe Compared,
Vít Hloušek and Lubomír Kopecek explain how socialist parties have
evolved from the 19th to the early 21st centuries. As the number of
people in traditional working-class occupations such as factory workers
and miners declined, socialists have successfully widened their appeal
to the middle class by diluting their ideology; however, there is still continuity between parties such as the SPD, the
Labour Party in Britain, and other socialist parties which remain part
of the same famille spirituelle, or ideological party family, as outlined by most political scientists. For many social democrats, Marxism is loosely held to be valuable for its emphasis on changing the world for a more just, better future.
History
During the late 19th century and the early 20th century, social
democracy was a broad labour movement within socialism that aimed to
replace private ownership with social ownership of the means of production, distribution and exchange, taking influence from both Marxism and the supporters of Ferdinand Lassalle. By 1868–1869, the socialism associated with Karl Marx had become the official theoretical basis of the first social democratic party established in Europe, the Social Democratic Workers' Party of Germany. In the early 20th century, the German social democratic politician Eduard Bernstein rejected orthodox Marxist ideas about the inevitable progression of history and the need for revolution, advancing instead the position that socialism should be grounded in ethical and moral arguments and achieved through gradual legislative reform. Bernstein's ideas were initially not well received; his party
maintained the position that reforms should be pursued only as a means
to an eventual revolution, not as a substitute for it. Yet, Bernstein's
ideas would have growing influence, particularly after the First World
War.
The Russian Revolution was a pivotal moment that furthered the division between reformists and revolutionary socialists. Those supporting the October Revolution renamed themselves as Communists while those opposing the Bolsheviks retained the Social Democrat label. While both groups technically shared the goal of a communist society that fully realized the principle of "from each according to his ability, to each according to his need", the Communists sought to distance themselves from to Social Democracy's association with reformism. The Communists also sought to distinguish themselves from the socialists that had supported the imperialist Great War and thus betrayed proletarian internationalism. This reformist–revolutionary division culminated in the German Revolution of 1919, in which the Communists wanted to overthrow the German government and establish a soviet republic like Russia, while the Social Democrats wanted to preserve it as what came to be known as the Weimar Republic. Thus social democracy went from a "Marxist revolutionary" doctrine into a form of "moderate parliamentary socialism".
The Bolsheviks split from the Second International and created their own separate Communist International
(Comintern) in 1919 that sought to rally revolutionary social democrats
together for socialist revolution. With this split, the reformists
founded the Labour and Socialist International
(LSI) in 1923. The LSI had a history of rivalry with the Comintern,
with which it competed over the leadership of the international
socialist and labour movement.
During the 1920s and 1930s, social democracy became dominant in
the socialist movement, mainly associated with reformist socialism while
communism represented revolutionary socialism. Under the influence of politicians like Carlo Rosselli in Italy, social democrats began disassociating themselves from orthodox Marxism altogether as represented by Marxism–Leninism, embracing liberal socialism, Keynesianism, and appealing to morality rather than any consistent systematic, scientific, or materialist worldview. Social democracy appealed to communitarian, corporatist, and sometimes nationalist sentiments while rejecting the economic and technological determinism generally characteristic of orthodox Marxism and economic liberalism.
By the post-World War II period and its economic consensus and expansion,
most social democrats in Europe had abandoned their ideological
connection to orthodox Marxism. They shifted their emphasis toward
social policy reform as a compromise between capitalism to socialism. According to Michael Harrington, the primary reason for this was the perspective that viewed the Stalinist-era Soviet Union as having succeeded in usurping the legacy of Marxism and distorting it in propaganda to justify totalitarianism. In its foundation, the Socialist International denounced the Bolshevik-inspired communist movement, "for [it] falsely claims a share in the Socialist tradition". Furthermore, core tenets of Marxism have been regarded by social
democrats as having become obsolete, including the prediction that the
working class was the decisive class with the development of capitalism.
In their view, this did not materialize in the aftermath of mass
industrialization during World War II.
In Britain, the social democratic Gaitskellites emphasized the goals of personal liberty, social welfare, and social equality. The Gaitskellites were part of a political consensus between the Labour and Conservative parties, famously dubbed Butskellism. Some social democratic Third Way figures such as Anthony Giddens and Tony Blair, who has described himself as a Christian socialist and a socialist in ethical terms, insist that they are socialists, for they claim to believe in the same values that their anti-Third Way critics do. According to those self-proclaimed social democratic modernizers, Clause IV's
open advocacy of state socialism was alienating potential middle-class
Labour supporters, and nationalization policies had been so thoroughly
attacked by neoliberal economists and politicians, including rhetorical
comparisons by the right of state-owned industry in the West to that in
the Soviet Union and the Eastern Bloc, and nationalizations and state
socialism became unpopular. Thatcherite Conservatives were adept at condemning state-owned enterprises as economically inefficient. For the Gaitskellites, nationalization was not essential to achieve all major socialist objectives; public ownership and nationalization were not explicitly rejected but were seen as merely one of numerous useful devices. According to social democratic modernizers like Blair, nationalization policies had become politically unviable by the 1990s.
During the Third Way
development of social democracy, social democrats adjusted to the
neoliberal political climate that had existed since the 1980s. Those
social democrats recognized that outspoken opposition to capitalism was politically non-viable and that accepting the powers that be, seeking to challenge free-market and laissez-faire variations of capitalism, was a more immediate concern. The Third Way stands for a modernized social democracy, but the social democracy that remained committed to the gradual
abolition of capitalism and social democrats opposed to the Third Way
merged into democratic socialism. Although social democracy originated as a revolutionary socialist or communist movement, one distinction between democratic socialism and social democracy is that the former can include revolutionary means. The latter proposes representative democracy under the rule of law as the only acceptable constitutional form of government.
During the Great Recession, Social Democratic parties in Europe increasingly adopted austerity as a policy response to the economic crisis, shifting away from the traditional Keynesian response of deficit spending. According to Björn Bremer, this shift in thinking was due to the influence of supply-side economics
on Social Democratic leaders and by electoral motivations whereby
Social Democrats wanted to appear economically competent to voters by
adopting orthodox fiscal policies.
Social democracy has some significant overlap in practical policy positions with democratic socialism, although they are usually distinguished from each other. In Britain, the revised version of Clause IV to the Labour Party Constitution, which was implemented in the 1990s by the New Labour faction led by Tony Blair, affirms a formal commitment to democratic socialism, describing it as a modernized form of social democracy; however, it no longer commits the party to public ownership of industry
and in its place advocates "the enterprise of the market and the rigour
of competition" along with "high quality public services either owned
by the public or accountable to them". Many social democrats "refer to themselves as socialists or democratic socialists", and some such as Blair "use or have used these terms interchangeably". Others argue that "there are clear differences between the three terms,
and preferred to describe their own political beliefs by using the term
'social democracy' only".
Democratic socialism represents social democracy before the 1970s, when the post-war displacement of Keynesianism by monetarism and neoliberalism caused many social democratic parties to adopt the Third Way ideology, accepting capitalism as the status quo for the time being and redefining socialism in a way that maintains the capitalist structure intact. Like modern social democracy, democratic socialism tends to follow a
gradual or evolutionary path to socialism rather than a revolutionary
one. Policies commonly supported are Keynesian and include some degree of regulation over the economy, social insurance schemes, public pension programs, and a gradual expansion of public ownership over major and strategic industries.
Internal debates
During the late 20th century, the social democracy and democratic
socialism labels were variously embraced, contested and rejected due to
the emergence of developments within the European left, such as Eurocommunism, the rise of neoliberalism, the fall of the Soviet Union and the Revolutions of 1989, the Third Way, and the rise of anti-austerity and Occupy movements due to the 2008 financial crisis and the Great Recession, the causes of which have been attributed by some to the neoliberal shift and deregulation economic policies. This latest development contributed to the rise of politicians, such as Jeremy Corbyn in Britain and Bernie Sanders in the United States, who rejected centrist politicians that supported triangulation within the Labour and Democratic parties.[159]
According to both right-wing critics and supporters alike, policies such as universal health care and education are "pure Socialism" because they are opposed to "the hedonism of capitalist society". Because of this overlap, democratic socialism refers to European socialism as represented by social democracy, especially in the United States, where it is tied to the New Deal. Some democratic socialists who follow social democracy support "practical", progressive
reforms of capitalism and are more concerned with administrating and
humanising it, with socialism relegated to the indefinite future. Other democratic socialists want to go beyond mere meliorist reforms and advocate the systematic transformation of the mode of production from capitalism to socialism.
In the United States
Despite the long history of overlap between the two, with social
democracy considered a form of democratic or parliamentary socialism and
social democrats calling themselves democratic socialists, democratic socialism is considered a misnomer in the United States. One issue is that social democracy is equated with wealthy countries in the Western world, especially Western Europe, Australia, and New Zealand, while democratic socialism is conflated either with the pink tide in Latin America, especially with Venezuela, or with communism in the form of Marxist–Leninist socialism as practised in the Soviet Union and other self-declared socialist states. Democratic socialism has been described as representing the "left-wing" or "socialist" tradition of the New Deal.
The lack of a strong and influential socialist movement in the United States has been linked to the Red Scare, and any ideology associated with socialism brings social stigma due to its association with authoritariansocialist states. Socialism has been used as a pejorative term by members of the political right to stop the implementation of liberal and progressive policies and proposals and to criticize the public figures trying to implement them. In contrast to Western Europe, Australia, and New Zealand, the United
States never witnessed the consolidation of a major socialist party, as its socialist movement remained comparatively weak. A major contributing factor to this divergence lies in the legacy of
slavery, which institutionalized profound and enduring racial divisions
within the American working class. Unlike the relatively cohesive labor
movements that emerged in societies lacking such a history, the U.S.
working class was stratified along racial lines, producing a segmented
labor market with distinct and often conflicting political priorities.
This structural fragmentation undermined the development of class
solidarity and posed a persistent obstacle to the formation of robust
left-wing politics. Consequently, racial stratification constrained mass
support for redistributive policies—particularly those concerning
taxation, social welfare, and economic equality—thereby limiting the
political viability of socialism in the American context. Although Americans may reject the idea that the United States has
characteristics of a European-style social democracy, it has been argued
by some observers that it has a comfortable social safety net, albeit severely underfunded in comparison to other Western countries. It has also been argued that many policies that may be considered socialist are popular but that socialism is not. Others, such as Tony Judt, described modern liberalism in the United States as representing European social democracy.
Policy regime
Social democracy rests on three fundamental features, namely: "(1)
parliamentary democracy, (2) an economy partly regulated by the state,
and (3) provision of social support to those in need". In practice, social democratic parties have been instrumental in the
social-liberal paradigm, lasting from the 1940s and 1970s, and called
such because it was developed by social liberals but implemented by social democrats. Since those policies were mostly implemented by social democrats, social liberalism is sometimes called social democracy. In Britain, the social-liberal Beveridge Report drafted by the Liberal economist William Beveridge influenced the Labour Party's social policies, such as the National Health Service and Labour's welfare state development. This social-liberal paradigm represented the post-war consensus and was
accepted across the political spectrum by conservatives, liberals and
socialists until the 1970s. Similarly, the neoliberal paradigm, which replaced the previous
paradigm, was accepted across the mainstream political parties,
including social democratic supporters of the Third Way. This has caused much controversy within the social democratic movement.
Role of the state
From the late 19th century until the mid to late 20th century, there
was greater public confidence in the idea of a state-managed economy
that was a major pillar of communism, and to a substantial degree by conservatives and left-liberals. Aside from anarchists and other libertarian socialists, there was confidence amongst socialists in the concept of state socialism
as being the most effective form of socialism. Some early British
social democrats in the 19th century and 20th century, such as the Fabians,
said that British society was already mostly socialist and that the
economy was significantly socialist through government-run enterprises
created by conservative and liberal governments which could be run for
the interests of the people through their representatives' influence, an argument echoed by some socialists in post-war Britain. Advents in economics and observation of the failure of state socialism in the Eastern Bloc countries and the Western world with the crisis and stagflation of the 1970s, combined with the neoliberal rebuke of state interventionism, resulted in socialists re-evaluating and redesigning socialism. Some social democrats have sought to keep what they deem are
socialism's core values while changing their position on state
involvement in the economy and retaining significant social regulations.
When nationalization
of large industries was relatively widespread in the 20th century until
the 1970s, it was not uncommon for commentators to describe some
European social democracies as democratic socialist states seeking to
move their countries toward a socialist economy. In 1956, leading Labour Party politician and British author Anthony Crosland said that capitalism had been abolished in Britain, although others such as Welshman Aneurin Bevan, Minister of Health in the first post-war Labour government and the architect of the National Health Service, disputed the claim. For Crosland and others who supported his views, Britain was a socialist state. According to Bevan, Britain had a socialist National Health Service, which opposed the hedonism of Britain's capitalist society.
Although, as in the rest of Europe, the laws of capitalism still operated fully and private enterprise dominated the economy, some political commentators stated that during the post-war period,
when social democratic parties were in power, countries such as Britain
and France were democratic socialist states. The same claim has been
applied to Nordic countries with the Nordic model. In the 1980s, the government of President François Mitterrand aimed to expand dirigism and attempted to nationalize all French banks, but this attempt faced opposition from the European Economic Community because it demanded a free-market economy among its members. Public ownership never accounted for more than 15–20% of capital formation, further dropping to 8% in the 1980s and below 5% in the 1990s after the rise of neoliberalism.
The collapse of the legitimacy of state socialism and Keynesian interventionism (with the discovery of the phenomenon of stagflation) has been an issue for social democracy. This has provoked re-thinking of how socialism should be achieved by social democrats, including changing views by social democrats on private
property—anti-Third Way social democrats such as Robert Corfe have
advocated a socialist form of private property as part of new socialism
(although Corfe technically objects to private property
as a term to collectively describe property that is not publicly owned
as being vague) and rejecting state socialism as a failure. Third Way social democracy was formed in response to what its
proponents saw as a crisis in the legitimacy of socialism—especially
state socialism—and the rising legitimacy of neoliberalism, especially laissez-faire capitalism. The Third Way's view of the crisis is criticized for being too simplistic. Others have criticized it because with the fall of state socialism, it
was possible for "a new kind of 'third way' socialism (combining social
ownership with markets and democracy), thereby heralding a
revitalization of the social democratic tradition"; however, it has been argued that the prospect of a new socialism was "a
chimera, a hopeful invention of Western socialists who had not
understood how 'actually existing socialism' had totally discredited any version of socialism among those who had lived under it".
Corporatism
Social democracy influenced the development of social corporatism, a form of economic tripartite corporatism based upon a social partnership between the interests of capital and labour,
involving collective bargaining between representatives of employers
and labour mediated by the government at the national level. During the post-war consensus, this form of social democracy has been a major component of the Nordic model and, to a lesser degree, the West European social market economies. The development of social corporatism began in Norway and Sweden in the 1930s and was consolidated in the 1960s and 1970s. The system was based upon the dual compromise of capital and labour as one component and the market and the state as the other. From the 1940s through the 1970s, defining features of social democracy
as a policy regime included Keynesian economic policies and industrial
agreements to balance the power of capital and labour and the welfare
state. This is especially associated with the Swedish Social Democrats. In the 1970s, social corporatism evolved into neo-corporatism, which replaced it. Neo-corporatism has represented an important concept of Third Way social democracy. Social democratic theorist Robin Archer wrote about the importance of social corporatism to social democracy in his work Economic Democracy: The Politics of a Feasible Socialism (1995). As a welfare state, social democracy is a specific type of welfare
state and policy regime described as being universalist, supportive of
collective bargaining, and more supportive of public provision of
welfare. It is especially associated with the Nordic model.
Analysis
Legacy
Social democratic policies were first adopted in the German Empire between the 1880s and 1890s, when the conservative Chancellor Otto von Bismarck put in place many social welfare proposals initially suggested by the Social Democrats to hinder their electoral success after he instituted the Anti-Socialist Laws, laying the ground of the first modern welfare state. Those policies were dubbed State Socialism by the liberal opposition, but Bismarck later accepted and re-appropriated the term. It was a set of social programs implemented in Germany that Bismarck initiated in 1883 as remedial measures to appease the working class and reduce support for socialism and the Social Democrats following earlier attempts to achieve the same objective through Bismarck's Anti-Socialist Laws. This did not prevent the Social Democrats from becoming the biggest party in parliament by 1912.
The United Nations World Happiness Report shows that the happiest nations are concentrated in social democratic nations, especially in Northern Europe, where the Nordic model is applied. This is at times attributed to the success of the social democratic Nordic model in the region, where similar democratic socialist, labourist, and social democratic parties dominated the region's political scene and laid the ground for their universal welfare states in the 20th century. The Nordic countries, including Denmark, Finland, Iceland, Norway, and
Sweden, as well as Greenland and the Faroe Islands, also ranks highest
on the metrics of real GDP per capita, economic equality, public health, life expectancy, solidarity, perceived freedom to make life choices, generosity, quality of life, and human development, while countries practising a neoliberal form of government have registered relatively poorer results. Similarly, several reports have listed Scandinavian and other social
democratic countries as ranking high on indicators such as civil liberties, democracy, press, peace, and perceived freedom from corruption. Numerous studies and surveys indicate that people live happier lives in
countries ruled by social democratic parties than those ruled by
neoliberal, centrist, and right-wing governments.
Other socialists criticize social democracy because it serves to
devise new means to strengthen the capitalist system, which conflicts
with the socialist goal of replacing capitalism with a socialist system. According to this view, social democracy fails to address the systemic
issues inherent in capitalism. The American democratic socialist
philosopher David Schweickart contrasts social democracy with democratic socialism by defining the former as an attempt to strengthen the welfare state
and the latter as an alternative economic system to capitalism.
According to Schweickart, the democratic socialist critique of social
democracy is that capitalism can never be sufficiently humanized and
that any attempt to suppress its economic contradictions will only cause
them to emerge elsewhere. He gives the example that attempts to reduce unemployment too much would result in inflation, and too much job security would erode labour discipline. In contrast to social democracy's mixed economy, democratic socialists advocate a post-capitalist economic system based on either a market economy combined with workers' self-management or on some form of participatory, decentralized planning of the economy.
Marxian
socialists argue that social democratic welfare policies cannot resolve
the fundamental structural issues of capitalism, such as cyclical fluctuations, exploitation, and alienation.
Accordingly, social democratic programs intended to ameliorate living
conditions in capitalism, such as unemployment benefits and taxation on
profits, creates further contradictions by further limiting the
efficiency of the capitalist system by reducing incentives for
capitalists to invest in further production. The welfare state only serves to legitimize and prolong the
exploitative and contradiction-laden system of capitalism to society's
detriment. Critics of contemporary social democracy, such as Jonas
Hinnfors, argue that when social democracy abandoned Marxism,
it also abandoned socialism and became a liberal capitalist movement,
effectively making social democrats similar to non-socialist parties
like the Democratic Party in the United States.
Market socialism
is also critical of social democratic welfare states. While one common
goal of both concepts is to achieve greater social and economic
equality, market socialism does so through changes in enterprise
ownership and management. Social democracy attempts to do so by
subsidies and taxes on privately owned enterprises to finance welfare
programs. Franklin Delano Roosevelt III (grandson of United States President Franklin D. Roosevelt) and David Belkin criticize social democracy for maintaining a property-owning capitalist class
with an active interest in reversing social democratic welfare policies
and a disproportionate amount of power as a class to influence
government policy. The economists John Roemer and Pranab Bardhan point out that social democracy requires a strong labour movement
to sustain its heavy redistribution through taxes and that it is
idealistic to think such redistribution can be accomplished in other
countries with weaker labour movements, noting that social democracy in
Scandinavian countries has been in decline as the labour movement
weakened.
Some critics say social democracy abandoned socialism in the 1930s by endorsing Keynesian welfare capitalism. The democratic socialist political theorist Michael Harrington argued that social democracy historically supported Keynesianism
as part of a "social democratic compromise" between capitalism and
socialism. Although this compromise did not allow for the immediate
creation of socialism, it created welfare states and "recognized
noncapitalist, and even anticapitalist, principles of human need over
and above the imperatives of profit". Social democrats in favour of the Third Way
have been accused of endorsing capitalism, including anti-Third Way
social democrats who have accused Third Way proponents such as Anthony Giddens of being anti-social democratic and anti-socialist in practice. Some critics and analysts argue that many prominent social democratic parties, such as the Labour Party in Britain and the Social Democratic Party of Germany,
even while maintaining references to socialism and declaring themselves
democratic socialist parties, have abandoned socialism in practice,
whether unwillingly or not.
Social democracy's reformism has been criticized by both the left and right, on the grounds that if reformist socialists were left to govern a
capitalist economy, they would have to do so according to capitalist,
not socialist, logic. For example, Joseph Schumpeter writes in Capitalism, Socialism and Democracy
(1942): "Socialists had to govern in an essentially capitalist world...
a social and economic system that would not function except on
capitalist lines.... If they were to run it, they would have to run it
according to its own logic. They would have to 'administer' capitalism". Similarly, Irving Kristol
argued: "Democratic socialism turns out to be an inherently unstable
compound, a contradiction in terms. Every social democratic party, once
in power, soon finds itself choosing, at one point after another,
between the socialist society it aspires to and the liberal society that
lathered it". Joseph Stalin was a vocal critic of reformist social democrats, later coining the term social fascism to describe social democracy in the 1930s because, in this period, it embraced a similar corporatist economic model to the model supported by fascism. This view was adopted by the Communist International, which argued that capitalist society had entered the Third Period in which a proletarian revolution was imminent but could be prevented by social democrats and other fascist forces.
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