Positive feedback

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https://en.wikipedia.org/wiki/Positive_feedback

Causal loop diagram that depicts the causes of a stampede as a positive feedback loop. Alarm or panic can sometimes be spread by positive feedback among a herd of animals to cause a stampede.

In sociology a network effect can quickly create the positive feedback of a bank run. The above photo is of the UK Northern Rock 2007 bank run.

Positive feedback (exacerbating feedback, self-reinforcing feedback) is a process that occurs in a feedback loop where the outcome of a process reinforces the inciting process to build momentum. As such, these forces can exacerbate the effects of a small disturbance. That is, the effects of a perturbation on a system include an increase in the magnitude of the perturbation. That is, A produces more of B which in turn produces more of A. In contrast, a system in which the results of a change act to reduce or counteract it has negative feedback. Both concepts play an important role in science and engineering, including biology, chemistry, and cybernetics.

Mathematically, positive feedback is defined as a positive loop gain around a closed loop of cause and effect. That is, positive feedback is in phase with the input, in the sense that it adds to make the input larger. Positive feedback tends to cause system instability. When the loop gain is positive and above 1, there will typically be exponential growth, increasing oscillations, chaotic behavior or other divergences from equilibrium.^[3] System parameters will typically accelerate towards extreme values, which may damage or destroy the system, or may end with the system latched into a new stable state. Positive feedback may be controlled by signals in the system being filtered, damped, or limited, or it can be cancelled or reduced by adding negative feedback.

Positive feedback is used in digital electronics to force voltages away from intermediate voltages into '0' and '1' states. On the other hand, thermal runaway is a type of positive feedback that can destroy semiconductor junctions. Positive feedback in chemical reactions can increase the rate of reactions, and in some cases can lead to explosions. Positive feedback in mechanical design causes tipping-point, or over-centre, mechanisms to snap into position, for example in switches and locking pliers. Out of control, it can cause bridges to collapse. Positive feedback in economic systems can cause boom-then-bust cycles. A familiar example of positive feedback is the loud squealing or howling sound produced by audio feedback in public address systems: the microphone picks up sound from its own loudspeakers, amplifies it, and sends it through the speakers again.

Platelet clotting demonstrates positive feedback. The damaged blood vessel wall releases chemicals that initiate the formation of a blood clot through platelet congregation. As more platelets gather, more chemicals are released that speed up the process. The process gets faster and faster until the blood vessel wall is completely sealed and the positive feedback loop has ended. The exponential form of the graph illustrates the positive feedback mechanism.

Overview

Positive feedback enhances or amplifies an effect by it having an influence on the process which gave rise to it. For example, when part of an electronic output signal returns to the input, and is in phase with it, the system gain is increased. The feedback from the outcome to the originating process can be direct, or it can be via other state variables. Such systems can give rich qualitative behaviors, but whether the feedback is instantaneously positive or negative in sign has an extremely important influence on the results. Positive feedback reinforces and negative feedback moderates the original process. Positive and negative in this sense refer to loop gains greater than or less than zero, and do not imply any value judgements as to the desirability of the outcomes or effects. A key feature of positive feedback is thus that small disturbances get bigger. When a change occurs in a system, positive feedback causes further change, in the same direction.

Basic

A basic feedback system can be represented by this block diagram. In the diagram the + symbol is an adder and A and B are arbitrary causal functions.

A simple feedback loop is shown in the diagram. If the loop gain AB is positive, then a condition of positive or regenerative feedback exists.

If the functions A and B are linear and AB is smaller than unity, then the overall system gain from the input to output is finite but can be very large as AB approaches unity. In that case, it can be shown that the overall or loop gain from input to output is:

${\displaystyle G_c=A/(1-AB)}$

When AB > 1, the system is unstable, so does not have a well-defined gain; the gain may be called infinite.

Thus depending on the feedback, state changes can be convergent, or divergent. The result of positive feedback is to augment changes, so that small perturbations may result in big changes.

A system in equilibrium in which there is positive feedback to any change from its current state may be unstable, in which case the system is said to be in an unstable equilibrium. The magnitude of the forces that act to move such a system away from its equilibrium is an increasing function of the distance of the state from the equilibrium.

Positive feedback does not necessarily imply instability of an equilibrium, for example stable on and off states may exist in positive-feedback architectures.

Hysteresis

Main article: Hysteresis

Hysteresis causes the output value to depend on the history of the input.

In a Schmitt trigger circuit, feedback to the non-inverting input of an amplifier pushes the output directly away from the applied voltage towards the maximum or minimum voltage the amplifier can generate.

In the real world, positive feedback loops typically do not cause ever-increasing growth but are modified by limiting effects of some sort. According to Donella Meadows:

"Positive feedback loops are sources of growth, explosion, erosion, and collapse in systems. A system with an unchecked positive loop ultimately will destroy itself. That's why there are so few of them. Usually, a negative loop will kick in sooner or later."

Hysteresis, in which the starting point affects where the system ends up, can be generated by positive feedback. When the gain of the feedback loop is above 1, then the output moves away from the input: if it is above the input, then it moves towards the nearest positive limit, while if it is below the input then it moves towards the nearest negative limit.

Once it reaches the limit, it will be stable. However, if the input goes past the limit, then the feedback will change sign and the output will move in the opposite direction until it hits the opposite limit. The system therefore shows bistable behaviour.

Terminology

The terms positive and negative were first applied to feedback before World War II. The idea of positive feedback was already current in the 1920s with the introduction of the regenerative circuit.

Friis & Jensen (1924) described regeneration in a set of electronic amplifiers as a case where the "feed-back" action is positive in contrast to negative feed-back action, which they mention only in passing. Harold Stephen Black's classic 1934 paper first details the use of negative feedback in electronic amplifiers. According to Black:

"Positive feed-back increases the gain of the amplifier, negative feed-back reduces it."

According to Mindell (2002) confusion in the terms arose shortly after this:

"...Friis and Jensen had made the same distinction Black used between 'positive feed-back' and 'negative feed-back', based not on the sign of the feedback itself but rather on its effect on the amplifier's gain. In contrast, Nyquist and Bode, when they built on Black's work, referred to negative feedback as that with the sign reversed. Black had trouble convincing others of the utility of his invention in part because confusion existed over basic matters of definition."

These confusions, along with the everyday associations of positive with good and negative with bad, have led many systems theorists to propose alternative terms. For example, Donella Meadows prefers the terms reinforcing and balancing feedbacks.

Examples and applications

In electronics

A vintage style regenerative radio receiver. Due to the controlled use of positive feedback, sufficient amplification can be derived from a single vacuum tube or valve (centre).

Regenerative circuits were invented and patented in 1914 for the amplification and reception of very weak radio signals. Carefully controlled positive feedback around a single transistor amplifier can multiply its gain by 1,000 or more. Therefore, a signal can be amplified 20,000 or even 100,000 times in one stage, that would normally have a gain of only 20 to 50. The problem with regenerative amplifiers working at these very high gains is that they easily become unstable and start to oscillate. The radio operator has to be prepared to tweak the amount of feedback fairly continuously for good reception. Superregenerative recievers use even more gain. Modern radio receivers use the superheterodyne design, with many more amplification stages, but much more stable operation and no positive feedback.

The oscillation that can break out in a regenerative radio circuit is used in electronic oscillators. By the use of tuned circuits or a piezoelectric crystal (commonly quartz), the signal that is amplified by the positive feedback remains linear and sinusoidal. There are several designs for such harmonic oscillators, including the Armstrong oscillator, Hartley oscillator, Colpitts oscillator, and the Wien bridge oscillator. They all use positive feedback to create oscillations.

Many electronic circuits, especially amplifiers, incorporate negative feedback. This reduces their gain, but improves their linearity, input impedance, output impedance, and bandwidth, and stabilises all of these parameters, including the loop gain. These parameters also become less dependent on the details of the amplifying device itself, and more dependent on the feedback components, which are less likely to vary with manufacturing tolerance, age and temperature. The difference between positive and negative feedback for AC signals is one of phase: if the signal is fed back out of phase, the feedback is negative and if it is in phase the feedback is positive. One problem for amplifier designers who use negative feedback is that some of the components of the circuit will introduce phase shift in the feedback path. If there is a frequency (usually a high frequency) where the phase shift reaches 180°, then the designer must ensure that the amplifier gain at that frequency is very low (usually by low-pass filtering). If the loop gain (the product of the amplifier gain and the extent of the positive feedback) at any frequency is greater than one, then the amplifier will oscillate at that frequency (Barkhausen stability criterion). Such oscillations are sometimes called parasitic oscillations. An amplifier that is stable in one set of conditions can break into parasitic oscillation in another. This may be due to changes in temperature, supply voltage, adjustment of front-panel controls, or even the proximity of a person or other conductive item.

Amplifiers may oscillate gently in ways that are hard to detect without an oscilloscope, or the oscillations may be so extensive that only a very distorted or no required signal at all gets through, or that damage occurs. Low frequency parasitic oscillations have been called 'motorboating' due to the similarity to the sound of a low-revving exhaust note.

The effect of using a Schmitt trigger (B) instead of a comparator (A)

Many common digital electronic circuits employ positive feedback. While normal simple Boolean logic gates usually rely simply on gain to push digital signal voltages away from intermediate values to the values that are meant to represent Boolean '0' and '1', but many more complex gates use feedback. When an input voltage is expected to vary in an analogue way, but sharp thresholds are required for later digital processing, the Schmitt trigger circuit uses positive feedback to ensure that if the input voltage creeps gently above the threshold, the output is forced smartly and rapidly from one logic state to the other. One of the corollaries of the Schmitt trigger's use of positive feedback is that, should the input voltage move gently down again past the same threshold, the positive feedback will hold the output in the same state with no change. This effect is called hysteresis: the input voltage has to drop past a different, lower threshold to 'un-latch' the output and reset it to its original digital value. By reducing the extent of the positive feedback, the hysteresis-width can be reduced, but it can not entirely be eradicated. The Schmitt trigger is, to some extent, a latching circuit.

Positive feedback is a mechanism by which an output is enhanced, such as protein levels. However, in order to avoid any fluctuation in the protein level, the mechanism is inhibited stochastically (I), therefore when the concentration of the activated protein (A) is past the threshold ([I]), the loop mechanism is activated and the concentration of A increases exponentially if d[A]=k [A].

Illustration of an R-S ('reset-set') flip-flop made from two digital nor gates with positive feedback. Red and black mean logical '1' and '0', respectively.

An electronic flip-flop, or "latch", or "bistable multivibrator", is a circuit that due to high positive feedback is not stable in a balanced or intermediate state. Such a bistable circuit is the basis of one bit of electronic memory. The flip-flop uses a pair of amplifiers, transistors, or logic gates connected to each other so that positive feedback maintains the state of the circuit in one of two unbalanced stable states after the input signal has been removed until a suitable alternative signal is applied to change the state. Computer random access memory (RAM) can be made in this way, with one latching circuit for each bit of memory.

Thermal runaway occurs in electronic systems because some aspect of a circuit is allowed to pass more current when it gets hotter, then the hotter it gets, the more current it passes, which heats it some more and so it passes yet more current. The effects are usually catastrophic for the device in question. If devices have to be used near to their maximum power-handling capacity, and thermal runaway is possible or likely under certain conditions, improvements can usually be achieved by careful design.

A phonograph turntable is prone to acoustic feedback.

Audio and video systems can demonstrate positive feedback. If a microphone picks up the amplified sound output of loudspeakers in the same circuit, then howling and screeching sounds of audio feedback (at up to the maximum power capacity of the amplifier) will be heard, as random noise is re-amplified by positive feedback and filtered by the characteristics of the audio system and the room.

Audio and live music

Audio feedback (also known as acoustic feedback, simply as feedback, or the Larsen effect) is a special kind of positive feedback which occurs when a sound loop exists between an audio input (for example, a microphone or guitar pickup) and an audio output (for example, a loudly-amplified loudspeaker). In this example, a signal received by the microphone is amplified and passed out of the loudspeaker. The sound from the loudspeaker can then be received by the microphone again, amplified further, and then passed out through the loudspeaker again. The frequency of the resulting sound is determined by resonance frequencies in the microphone, amplifier, and loudspeaker, the acoustics of the room, the directional pick-up and emission patterns of the microphone and loudspeaker, and the distance between them. For small PA systems the sound is readily recognized as a loud squeal or screech.

Feedback is almost always considered undesirable when it occurs with a singer's or public speaker's microphone at an event using a sound reinforcement system or PA system. Audio engineers use various electronic devices, such as equalizers and, since the 1990s, automatic feedback detection devices to prevent these unwanted squeals or screeching sounds, which detract from the audience's enjoyment of the event. On the other hand, since the 1960s, electric guitar players in rock music bands using loud guitar amplifiers and distortion effects have intentionally created guitar feedback to create a desirable musical effect. "I Feel Fine" by the Beatles marks one of the earliest examples of the use of feedback as a recording effect in popular music. It starts with a single, percussive feedback note produced by plucking the A string on Lennon's guitar. Artists such as the Kinks and the Who had already used feedback live, but Lennon remained proud of the fact that the Beatles were perhaps the first group to deliberately put it on vinyl. In one of his last interviews, he said, "I defy anybody to find a record—unless it's some old blues record in 1922—that uses feedback that way."

The principles of audio feedback were first discovered by Danish scientist Søren Absalon Larsen. Microphones are not the only transducers subject to this effect. Phone cartridges can do the same, usually in the low-frequency range below about 100 Hz, manifesting as a low rumble. Jimi Hendrix was an innovator in the intentional use of guitar feedback in his guitar solos to create unique sound effects. He helped develop the controlled and musical use of audio feedback in electric guitar playing, and later Brian May was a famous proponent of the technique.

Video feedback

Video

Similarly, if a video camera is pointed at a monitor screen that is displaying the camera's own signal, then repeating patterns can be formed on the screen by positive feedback. This video feedback effect was used in the opening sequences to the first ten seasons of the television program Doctor Who.

Switches

In electrical switches, including bimetallic strip based thermostats, the switch usually has hysteresis in the switching action. In these cases hysteresis is mechanically achieved via positive feedback within a tipping point mechanism. The positive feedback action minimises the length of time arcing occurs for during the switching and also holds the contacts in an open or closed state.

In biology

Positive feedback is the amplification of a body's response to a stimulus. For example, in childbirth, when the head of the fetus pushes up against the cervix (1) it stimulates a nerve impulse from the cervix to the brain (2). When the brain is notified, it signals the pituitary gland to release a hormone called oxytocin(3). Oxytocin is then carried via the bloodstream to the uterus (4) causing contractions, pushing the fetus towards the cervix eventually inducing childbirth.

In physiology

A number of examples of positive feedback systems may be found in physiology.

• One example is the onset of contractions in childbirth, known as the Ferguson reflex. When a contraction occurs, the hormone oxytocin causes a nerve stimulus, which stimulates the hypothalamus to produce more oxytocin, which increases uterine contractions. This results in contractions increasing in amplitude and frequency.
• Another example is the process of blood clotting. The loop is initiated when injured tissue releases signal chemicals that activate platelets in the blood. An activated platelet releases chemicals to activate more platelets, causing a rapid cascade and the formation of a blood clot.
• Lactation also involves positive feedback in that as the baby suckles on the nipple there is a nerve response into the spinal cord and up into the hypothalamus of the brain, which then stimulates the pituitary gland to produce more prolactin to produce more milk.
• A spike in estrogen during the follicular phase of the menstrual cycle causes ovulation.
• The generation of nerve signals is another example, in which the membrane of a nerve fibre causes slight leakage of sodium ions through sodium channels, resulting in a change in the membrane potential, which in turn causes more opening of channels, and so on (Hodgkin cycle). So a slight initial leakage results in an explosion of sodium leakage which creates the nerve action potential.
• In excitation–contraction coupling of the heart, an increase in intracellular calcium ions to the cardiac myocyte is detected by ryanodine receptors in the membrane of the sarcoplasmic reticulum which transport calcium out into the cytosol in a positive feedback physiological response.

In most cases, such feedback loops culminate in counter-signals being released that suppress or break the loop. Childbirth contractions stop when the baby is out of the mother's body. Chemicals break down the blood clot. Lactation stops when the baby no longer nurses.^[27]

In gene regulation

Positive feedback is a well-studied phenomenon in gene regulation, where it is most often associated with bistability. Positive feedback occurs when a gene activates itself directly or indirectly via a double negative feedback loop. Genetic engineers have constructed and tested simple positive feedback networks in bacteria to demonstrate the concept of bistability. A classic example of positive feedback is the lac operon in E. coli. Positive feedback plays an integral role in cellular differentiation, development, and cancer progression, and therefore, positive feedback in gene regulation can have significant physiological consequences. Random motions in molecular dynamics coupled with positive feedback can trigger interesting effects, such as create population of phenotypically different cells from the same parent cell. This happens because noise can become amplified by positive feedback. Positive feedback can also occur in other forms of cell signaling, such as enzyme kinetics or metabolic pathways.

In evolutionary biology

Positive feedback loops have been used to describe aspects of the dynamics of change in biological evolution. For example, beginning at the macro level, Alfred J. Lotka (1945) argued that the evolution of the species was most essentially a matter of selection that fed back energy flows to capture more and more energy for use by living systems. At the human level, Richard D. Alexander (1989) proposed that social competition between and within human groups fed back to the selection of intelligence thus constantly producing more and more refined human intelligence. Crespi (2004) discussed several other examples of positive feedback loops in evolution. The analogy of evolutionary arms races provides further examples of positive feedback in biological systems.

During the Phanerozoic the biodiversity shows a steady but not monotonic increase from near zero to several thousands of genera.

It has been shown that changes in biodiversity through the Phanerozoic correlate much better with hyperbolic model (widely used in demography and macrosociology) than with exponential and logistic models (traditionally used in population biology and extensively applied to fossil biodiversity as well). The latter models imply that changes in diversity are guided by first-order positive feedback (more ancestors, more descendants) or a negative feedback arising from resource limitation. The hyperbolic model implies a second-order positive feedback. The hyperbolic pattern of the world population growth has been demonstrated (see below) to arise from second-order positive feedback between the population size and the rate of technological growth. The hyperbolic character of biodiversity growth can be similarly accounted for by a positive feedback between the diversity and community structure complexity. It has been suggested that the similarity between the curves of biodiversity and human population probably comes from the fact that both are derived from the interference of the hyperbolic trend (produced by the positive feedback) with cyclical and stochastic dynamics.

Immune system

A cytokine storm, or hypercytokinemia is a potentially fatal immune reaction consisting of a positive feedback loop between cytokines and immune cells, with highly elevated levels of various cytokines. In normal immune function, positive feedback loops can be utilized to enhance the action of B lymphocytes. When a B cell binds its antibodies to an antigen and becomes activated, it begins releasing antibodies and secreting a complement protein called C3. Both C3 and a B cell's antibodies can bind to a pathogen, and when a B cell has its antibodies bind to a pathogen with C3, it speeds up that B cell's secretion of more antibodies and more C3, thus creating a positive feedback loop.

Cell death

Apoptosis is a caspase-mediated process of cellular death, whose aim is the removal of long-lived or damaged cells. A failure of this process has been implicated in prominent conditions such as cancer or Parkinson's disease. The very core of the apoptotic process is the auto-activation of caspases, which may be modelled via a positive-feedback loop. This positive feedback exerts an auto-activation of the effector caspase by means of intermediate caspases. When isolated from the rest of apoptotic pathway, this positive feedback presents only one stable steady state, regardless of the number of intermediate activation steps of the effector caspase. When this core process is complemented with inhibitors and enhancers of caspases effects, this process presents bistability, thereby modelling the alive and dying states of a cell.

In psychology

Winner (1996) described gifted children as driven by positive feedback loops involving setting their own learning course, this feeding back satisfaction, thus further setting their learning goals to higher levels and so on. Winner termed this positive feedback loop as a rage to master. Vandervert (2009a, 2009b) proposed that the child prodigy can be explained in terms of a positive feedback loop between the output of thinking/performing in working memory, which then is fed to the cerebellum where it is streamlined, and then fed back to working memory thus steadily increasing the quantitative and qualitative output of working memory. Vandervert also argued that this working memory/cerebellar positive feedback loop was responsible for language evolution in working memory.

In economics

Markets with social influence

Product recommendations and information about past purchases have been shown to influence consumers' choices significantly whether it is for music, movie, book, technological, and other type of products. Social influence often induces a rich-get-richer phenomenon (Matthew effect) where popular products tend to become even more popular.

Market dynamics

According to the theory of reflexivity advanced by George Soros, price changes are driven by a positive feedback process whereby investors' expectations are influenced by price movements so their behaviour acts to reinforce movement in that direction until it becomes unsustainable, whereupon the feedback drives prices in the opposite direction.

In social media

Programs such as Facebook and Twitter depend on positive feedback to create interest in topics and drive the take-up of the media. In the age of smartphones and social media, the feedback loop has created a craze for virtual validation in the form of likes, shares, and FOMO (fear of missing out). This is intensified by the use of bots which are designed to respond to particular words or themes and transmit posts more widely.

What is called negative feedback in social media should often be regarded as positive feedback in this context. Outrageous statements and negative comments often produce much more feedback than positive comments.

Systemic risk

Systemic risk is the risk that an amplification or leverage or positive feedback process presents to a system. This is usually unknown, and under certain conditions, this process can amplify exponentially and rapidly lead to destructive or chaotic behaviour. A Ponzi scheme is a good example of a positive-feedback system: funds from new investors are used to pay out unusually high returns, which in turn attract more new investors, causing rapid growth toward collapse. W. Brian Arthur has also studied and written on positive feedback in the economy (e.g. W. Brian Arthur, 1990). Hyman Minsky proposed a theory that certain credit expansion practices could make a market economy into "a deviation amplifying system" that could suddenly collapse, sometimes called a Minsky moment.

Simple systems that clearly separate the inputs from the outputs are not prone to systemic risk. This risk is more likely as the complexity of the system increases because it becomes more difficult to see or analyze all the possible combinations of variables in the system even under careful stress testing conditions. The more efficient a complex system is, the more likely it is to be prone to systemic risks because it takes only a small amount of deviation to disrupt the system. Therefore, well-designed complex systems generally have built-in features to avoid this condition, such as a small amount of friction, or resistance, or inertia, or time delay to decouple the outputs from the inputs within the system. These factors amount to an inefficiency, but they are necessary to avoid instabilities.

The 2010 Flash Crash incident was blamed on the practice of high-frequency trading (HFT), although whether HFT really increases systemic risk remains controversial.

Human population growth

Main article: Human population growth

Agriculture and human population can be considered to be in a positive feedback mode, which means that one drives the other with increasing intensity. It is suggested that this positive feedback system will end sometime with a catastrophe, as modern agriculture is using up all of the easily available phosphate and is resorting to highly efficient monocultures which are more susceptible to systemic risk.

Technological innovation and human population can be similarly considered, and this has been offered as an explanation for the apparent hyperbolic growth of the human population in the past, instead of a simpler exponential growth. It is proposed that the growth rate is accelerating because of second-order positive feedback between population and technology. Technological growth increases the carrying capacity of land for people, which leads to a growing population, and this in turn drives further technological growth.

Prejudice, social institutions and poverty

Gunnar Myrdal described a vicious circle of increasing inequalities, and poverty, which is known as circular cumulative causation.

James Moody, Assistant Professor at Ohio State University, states that students who self-segregate or grow up in segregated environments have "little meaningful exposure to other races because they never form relationships with students of another race...[; as a result,...] they are viewing other racial groups at a social distance, which can bolster stereotypes," which ultimately causes a positive feedback loop in which segregated groups become more prejudiced, polarized, and segregated against each other, similar to that of political polarization.

In meteorology

Drought intensifies through positive feedback. A lack of rain decreases soil moisture, which kills plants or causes them to release less water through transpiration. Both factors limit evapotranspiration, the process by which water vapour is added to the atmosphere from the surface, and add dry dust to the atmosphere, which absorbs water. Less water vapour means both low dew point temperatures and more efficient daytime heating, decreasing the chances of humidity in the atmosphere leading to cloud formation. Lastly, without clouds, there cannot be rain, and the loop is complete.

In climatology

See also: Climate change feedback and Runaway greenhouse effect

 

Human-caused increases in greenhouse gases stimulate positive feedback in global warming.

 

Some effects of global warming can either enhance (positive feedbacks) or inhibit (negative feedbacks) warming

 

Globally, wildfires and deforestation have reduced forests' net absorption of greenhouse gases, reducing their effectiveness at mitigating climate change. Global warming increases forest fires that release more greenhouse gases, creating a positive feedback loop that causes more warming.

 

Over recent decades, "forest disturbance" (damage) by fire has increased in most of the planet's forest zones. The increase in area, frequency, and severity of forest fires creates a positive feedback that increases global warming.

Climate forcings may push a climate system in the direction of warming or cooling, for example, increased atmospheric concentrations of greenhouse gases cause warming at the surface. Forcings are external to the climate system and feedbacks are internal processes of the system. Some feedback mechanisms act in relative isolation to the rest of the climate system while others are tightly coupled. Forcings, feedbacks and the dynamics of the climate system determine how much and how fast the climate changes. The main positive feedback in global warming is the tendency of warming to increase the amount of water vapour in the atmosphere, which in turn leads to further warming. The main negative feedback comes from the Stefan–Boltzmann law, the amount of heat radiated from the Earth into space is proportional to the fourth power of the temperature of Earth's surface and atmosphere.

Other examples of positive feedback subsystems in climatology include:

• A warmer atmosphere melts ice, changing the albedo (surface reflectivity), which further warms the atmosphere.
• Methane hydrates can be unstable so that a warming ocean could release more methane, which is also a greenhouse gas.
• Peat, occurring naturally in peat bogs, contains carbon. When peat dries it decomposes, and may additionally burn. Peat also releases nitrous oxide.
• Global warming affects the cloud distribution. Clouds at higher altitudes enhance the greenhouse effects, while low clouds mainly reflect back sunlight, having opposite effects on temperature.

The Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report states that "Anthropogenic warming could lead to some effects that are abrupt or irreversible, depending upon the rate and magnitude of the climate change."

In sociology

A self-fulfilling prophecy is a social positive feedback loop between beliefs and behaviour: if enough people believe that something is true, their behaviour can make it true, and observations of their behaviour may in turn increase belief. A classic example is a bank run.

Another sociological example of positive feedback is the network effect. When more people are encouraged to join a network this increases the reach of the network therefore the network expands ever more quickly. A viral video is an example of the network effect in which links to a popular video are shared and redistributed, ensuring that more people see the video and then re-publish the links. This is the basis for many social phenomena, including Ponzi schemes and chain letters. In many cases, population size is the limiting factor to the feedback effect.

In political science

In politics, institutions can reinforce norms, which can subsequently be a source of positive feedback. This rationale is frequently utilized to comprehend public policy processes, which may be dissected into a sequence of events. Self-reinforcing processes are understood to be affected by positive feedback mechanisms (e.g., supportive policy constituencies). Conversely, unsuccessful policy processes encounter negative feedback mechanisms (e.g., veto points with veto power).

A comparative illustration of policy feedback can be observed in the economic foreign policies of Brazil and China, particularly in their execution of state capitalism tactics during the 1990s and 2000s. Although both nations initially embraced similar state capitalist ideas, their paths in executing economic policies diverged over time due to distinct incentives. In China, a positive feedback mechanism reinforced previous policies, whereas in Brazil, negative feedback mechanisms compelled the country to abandon state capitalism policies and dynamics.

In chemistry

If a chemical reaction causes the release of heat, and the reaction itself happens faster at higher temperatures, then there is a high likelihood of positive feedback. If the heat produced is not removed from the reactants fast enough, thermal runaway can occur and very quickly lead to a chemical explosion.

In conservation

Many wildlife are hunted for their parts which can be quite valuable. The closer to extinction that targeted species become, the higher the price there is on their parts.

Post-capitalism

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Post-capitalism

Post-capitalism is in part a hypothetical state in which the economic systems of the world can no longer be described as forms of capitalism. Various individuals and political ideologies have speculated on what would define such a world. According to classical Marxist and social evolutionary theories, post-capitalist societies may come about as a result of spontaneous evolution as capitalism becomes obsolete. Others propose models to intentionally replace capitalism, most notably socialism, communism, anarchism, nationalism and degrowth.

History

In 1993, Peter Drucker outlined a possible evolution of capitalistic society in his book Post-Capitalist Society.

In 1993, Peter Drucker outlined a possible evolution of capitalistic society in his book Post-Capitalist Society. This states that knowledge, rather than capital, land, or labor, is the new basis of wealth. The classes of a fully post-capitalist society are expected to be divided into knowledge workers or service workers, in contrast to the capitalists and proletarians of a capitalist society. Drucker estimated the transformation to post-capitalism would be completed in 2010–2020. Drucker also argued for rethinking the concept of intellectual property by creating a universal licensing system.

In 2015, according to Paul Mason, several factors — the rise of income inequality, repeating cycles of boom and bust, and capitalism's contributions to climate change — led economists, political thinkers and philosophers to start seriously considering how a post-capitalistic society would look and function. Post-capitalism is expected to be made possible with further advances in automation and information technology – both of which are effectively causing production costs to trend toward zero.

Nick Srnicek and Alex Williams identify a crisis in capitalism's ability and willingness to employ all members of society, arguing that: "there is a growing population of people that are situated outside formal, waged work, with minimal welfare benefits, informal subsistence work, or by illegal means".

Variations

Heritage check system

Main article: For Us, The Living: A Comedy of Customs

Robert Heinlein

Heritage check system is a socioeconomic plan that retains a market economy but removes fractional reserve lending power from banks and limits government printing of money to offset deflation. Money printed is used to buy materials to back the currency and pay for government programs in lieu of taxes, with the remainder to be split evenly among all citizens to stimulate the economy (termed a "heritage check", for which the system is named). The original author of the idea, Robert Heinlein, stated in his book For Us, The Living: A Comedy of Customs, that the system would be self-reinforcing and would eventually result in regular heritage checks able to provide a modest living for most citizens.

Economic democracy

Economic democracy is a socioeconomic philosophy that establishes democratic control of firms by their workers and social control of investment by a network of public banks.

Participatory economy

Main article: Participatory economy

In his book Of the People, By the People: The Case for a Participatory Economy, Robin Hahnel describes a post-capitalist economy called the participatory economy.

Hahnel argues that a participatory economy will return empathy to our purchasing choices. Capitalism removes the knowledge of how and by whom a product was made: "When we eat a salad the market systematically deletes information about the migrant workers who picked it".

Socialism

Main article: Socialism

Paul Mason

Michael Albert

Socialism often implies common ownership of companies and a planned economy, though as an inherently pluralistic ideology, it is argued whether either are essential features. In his book PostCapitalism: A Guide to our Future, Paul Mason argues that centralized planning, even with the advanced technology of today, is unachievable.

In UK politics, strands of Corbynism and the Labour party have adopted this 'post-capitalist' tendency.

Permaculture

Main article: Permaculture

Permaculture is defined by its co-originator Bill Mollison as: "The conscious design and maintenance of agriculturally productive systems which have the diversity, stability, and resilience of natural ecosystems".

PROUT

Main article: Progressive utilization theory

Progressive utilization theory (PROUT) is a socioeconomic and political philosophy created by the Indian philosopher and spiritual leader Prabhat Ranjan Sarkar in 1959. PROUT includes the decentralization of the economy; economic democracy; development of cooperatives; provision of all working members of society with five basic needs: food, clothing, shelter, education, medical care; and systematic solution of environmental problems through technological development and limitation of consumption.

Agrowth

Agrowth ("agnostic or atheistic about growth") is a concept in economic policy according to which it is preferable to be indifferent to the growth of gross domestic product (GDP growth) when devising policies to further economic and societal progress. The reasoning behind agrowth is that GDP growth does not correlate closely with such progress.

The concept has been particularly discussed in the context of environmental policy, where it is opposed to both green growth and degrowth. Agrowth is supported by many scientists.

For example environmental economist Jeroen C. J. M. van den Bergh argues for an agnostic attitude toward economic growth. According to him, environmental policy should not be aimed at pursuing or avoiding growth in the hope of reducing environmental damage, but at direct deployment of effective instruments such as pricing externalities (for example, via environmental taxes or emission rights). Whether the economy grows, stagnates or shrinks as a result is of secondary importance.

Post-growth

Post-growth is an umbrella term that refers to a broad family of economic, ecological, and political perspectives responding to the limits-to-growth dilemma —the recognition that infinite economic growth is biophysically unsustainable on a finite planet. Central to post-growth thinking is the shift of the focus out of GDP growth as the main goal of the economy. Instead, well-being becomes the main objective. Post-growth puts emphasis on decoupling societal well-being from economic growth, advocating for the possibility of prosperity beyond growth.

Scholars define post-growth in different ways. Some describe it as comprising two main categories: degrowth (a stance advocating for a deliberate and equitable reduction in material consumption and economic activity) and agrowth (an agnostic stance towards economic growth, holding that policymakers should remain neutral about GDP growth because it may have either positive or negative effects on environmental or social objectives). According to others it serves as an umbrella term encompassing research in Doughnut and wellbeing economics, steady-state economics, and degrowth.

A systematic review of academic literature found that the distinction between degrowth and post-growth is often unclear, with many authors using post-growth as a catch-all term to avoid the strong connotations associated with degrowth.

Steady-state economy

A steady-state economy is an economy made up of a constant stock of physical wealth (capital) and a constant population size. In effect, such an economy does not grow in the course of time. The term usually refers to the national economy of a particular country, but it is also applicable to the economic system of a city, a region, or the entire world. Early in the history of economic thought, classical economist Adam Smith of the 18th century developed the concept of a stationary state of an economy: Smith believed that any national economy in the world would sooner or later settle in a final state of stationarity.

Since the 1970s, the concept of a steady-state economy has been associated mainly with the work of leading ecological economist Herman Daly. As Daly's concept of a steady-state includes the ecological analysis of natural resource flows through the economy, his concept differs from the original classical concept of a stationary state. One other difference is that Daly recommends immediate political action to establish the steady-state economy by imposing permanent government restrictions on all resource use, whereas economists of the classical period believed that the final stationary state of any economy would evolve by itself without any government intervention.

Critics of the steady-state economy usually object to it by arguing that resource decoupling, technological development, and the operation of market mechanisms are capable of overcoming resource scarcity, pollution, or population overshoot. On the other hand, proponents of the steady-state economy maintain that these objections remain insubstantial and mistaken, and that the need for a steady-state economy is becoming more compelling every day.

Degrowth

Degrowth aims to bring about a post-capitalist world through what Anitra Nelson describes as the reframing and recreation of economies so that they "respect the Earth's limits in order to achieve socio-political equity and ecological sustainability.' They note that degrowth is "distinctive within sustainability and justice movements due to a unique emphasis on growth as a driver of unsustainabilities and inequities." As such "Degrowth argues for a radical reduction in production and consumption, greater citizen participation in politics, and more diversity, especially within ecological systems and landscapes, along with a flourishing of creativity, care, and commoning — using renewable energy and materials.

Degrowth and MMT

Jason Hickel at the University of Oxford

Modern monetary theory (MMT) could enhance the degrowth movement in transitioning to a "post-growth, post-capitalist economy", according to economic anthropologist Jason Hickel. Towards this end, he suggests that the power of "the government's role as the issuer of currency" could be utilized to bring the economy back into balance with the natural world while at the same time reducing economic inequality by providing high quality universal basic services, implementing the rapid development of renewable energy infrastructure to completely phase out fossil fuels in a shorter period of time, and establishing a public job guarantee for 30 hours a week at a living wage doing decommodified, socially useful work in the public services sector, and also useful work in renewable energy development and ecosystem restoration. Hickel notes that providing a living wage at 30 hours a week also has the added benefit of shifting income from capital to labor. Furthermore, he adds that taxation can be used to "reduce demand in order to bring resource and energy use down to target levels," and specifically to reduce the purchasing power of the wealthy.

Technology as a driver of post-capitalism

Automation

Technological change that has driven unemployment has historically been due to 'mechanical-muscle' machines, which have reduced the need for human labor. Just as the use of horses for transport and other work was gradually made obsolete by the invention of the automobile, humans' jobs have also been affected throughout history. A modern example of this technological unemployment is the replacement of retail cashiers by self-service checkouts. The invention and development of 'mechanical-mind' processes or 'brain labor' is thought to threaten jobs at an unprecedented scale, with Oxford Professors Carl Benedikt Frey and Michael Osborne estimating that 47% of US jobs are at risk of automation.

Information technology

Post-capitalism is said to be possible due to major changes brought about by information technology in recent years. These changes have blurred the boundaries between work and free time and loosened the relationship between work and wages. Significantly, information is corroding the market's ability to form prices correctly. Information is abundant and information goods are freely replicable. Goods such as music, software or databases do have a production cost, but once made can be copied infinitely. If the normal price mechanism of capitalism prevails, then the price of any good which has essentially no cost of reproduction will fall towards zero. This lack of scarcity of those things is a problem in those models, which try to counter by developing monopolies in the form of giant tech companies to keep information scarce and commercial. But many significant commodities in the digital economy are now free and open-source, such as Linux, Firefox, Wikipedia and Open-source hardware.

Cognitarism

In 2025, early theoretical frameworks such as Cognitarism proposed socio-economic systems where artificial cognition itself, rather than human labour, was positioned as the primary driver of value creation.

Antiscience

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Antiscience

Antiscience is a set of attitudes and a form of anti-intellectualism that involves a rejection of science and the scientific method. People holding antiscientific views do not accept science as an objective method that can generate universal knowledge. Antiscience commonly manifests through rejection of scientific ideas such as climate change and evolution and the effectiveness of vaccination. It also includes pseudoscience, methods that claim to be scientific but reject the scientific method. Antiscience can lead to belief in false conspiracy theories and alternative medicine. Lack of trust in science has been linked to the promotion of political extremism, corruption and distrust in medical treatments.

History

In the early days of the Scientific Revolution, scientists such as Robert Boyle (1627–1691) found themselves in conflict with those such as Thomas Hobbes (1588–1679), who were skeptical of whether science was a satisfactory way to obtain genuine knowledge about the world.

Hobbes' stance is regarded by Ian Shapiro as an antiscience position:

In his Six Lessons to the Professors of Mathematics,...[published in 1656, Hobbes] distinguished 'demonstrable' fields, as 'those the construction of the subject whereof is in the power of the artist himself,' from 'indemonstrable' ones 'where the causes are to seek for.' We can only know the causes of what we make. So geometry is demonstrable, because 'the lines and figures from which we reason are drawn and described by ourselves' and 'civil philosophy is demonstrable, because we make the commonwealth ourselves.' But we can only speculate about the natural world, because 'we know not the construction, but seek it from the effects.'

In his book Reductionism: Analysis and the Fullness of Reality, published in 2000, Richard H. Jones wrote that Hobbes "put forth the idea of the significance of the nonrational in human behaviour". Jones goes on to group Hobbes with others he classes as "antireductionists" and "individualists", including Wilhelm Dilthey (1833–1911), Karl Marx (1818–1883), Jeremy Bentham (1748–1832) and J S Mill (1806–1873), later adding Karl Popper (1902–1994), John Rawls (1921–2002), and E. O. Wilson (1929–2021) to the list.

Jean-Jacques Rousseau, in his Discourse on the Arts and Sciences (1750), claimed that science can lead to immorality. "Rousseau argues that the progression of the sciences and arts has caused the corruption of virtue and morality" and his "critique of science has much to teach us about the dangers involved in our political commitment to scientific progress, and about the ways in which the future happiness of mankind might be secured". Nevertheless, Rousseau does not state in his Discourses that sciences are necessarily bad, and states that figures like René Descartes, Francis Bacon, and Isaac Newton should be held in high regard. In the conclusion to the Discourses, he says that these (aforementioned) can cultivate sciences to great benefit, and that morality's corruption is mostly because of society's bad influence on scientists.

William Blake (1757–1827) reacted strongly in his paintings and writings against the work of Isaac Newton (1642–1727), and is seen as being perhaps the earliest (and almost certainly the most prominent and enduring) example of what is seen by historians as the aesthetic or Romantic antiscience response. For example, in his 1795 poem "Auguries of Innocence", Blake describes the beautiful and natural robin redbreast imprisoned by what one might interpret as the materialistic cage of Newtonian mathematics and science. Blake's painting of Newton depicts the scientist "as a misguided hero whose gaze was directed only at sterile geometrical diagrams drawn on the ground". Blake thought that "Newton, Bacon, and Locke with their emphasis on reason were nothing more than 'the three great teachers of atheism, or Satan's Doctrine'...the picture progresses from exuberance and colour on the left, to sterility and blackness on the right. In Blake's view Newton brings not light, but night". In a 1940 poem, W.H. Auden summarises Blake's anti-scientific views by saying that he "[broke] off relations in a curse, with the Newtonian Universe".

One recent biographer of Newton considers him more as a renaissance alchemist, natural philosopher, and magician rather than a true representative of scientific Enlightenment, as popularized by Voltaire (1694–1778) and other Newtonians.

Antiscience issues are seen as a fundamental consideration in the historical transition from "pre-science" or "protoscience" such as that evident in alchemy. Many disciplines that pre-date the widespread adoption and acceptance of the scientific method, such as geometry and astronomy, are not seen as anti-science. However, some of the orthodoxies within those disciplines that predate a scientific approach (such as those orthodoxies repudiated by the discoveries of Galileo (1564–1642)) are seen as being a product of an anti-scientific stance.

Friedrich Nietzsche in The Gay Science (1882) questions scientific dogmatism:

"[...] in Science, convictions have no rights of citizenship, as is said with good reason. Only when they decide to descend to the modesty of a hypothesis, of a provisional experimental point of view, of a regulative fiction, maybe they be granted admission and even a certain value within the realm of knowledge – though always with the restriction that they remain under police supervision, under the police of mistrust. But does this not mean, more precisely considered, that a conviction may obtain admission to science only when it ceases to be a conviction? Would not the discipline of the scientific spirit begin with this, no longer to permit oneself any convictions? Probably that is how it is. But one must still ask whether it is not the case that, in order that this discipline could begin, a conviction must have been there already, and even such a commanding and unconditional one that it sacrificed all other convictions for its own sake. It is clear that Science too rests on a faith; there is no Science 'without presuppositions.' The question whether truth is needed must not only have been affirmed in advance, but affirmed to the extent that the principle, the faith, the conviction is expressed: 'nothing is needed more than truth, and in relation to it, everything else has only second-rate value".

The term "scientism", originating in science studies, was adopted and is used by sociologists and philosophers of science to describe the views, beliefs and behavior of strong supporters of applying ostensibly scientific concepts beyond its traditional disciplines. Specifically, scientism promotes science as the best or only objective means to determine normative and epistemological values. The term scientism is generally used critically, implying a cosmetic application of science in unwarranted situations considered not amenable to application of the scientific method or similar scientific standards. The word is commonly used in a pejorative sense, applying to individuals who seem to be treating science in a similar way to a religion. The term reductionism is occasionally used in a similarly pejorative way (as a more subtle attack on scientists). However, some scientists feel comfortable being labelled as reductionists, while agreeing that there might be conceptual and philosophical shortcomings of reductionism.

However, non-reductionist (see Emergentism) views of science have been formulated in varied forms in several scientific fields like statistical physics, chaos theory, complexity theory, cybernetics, systems theory, systems biology, ecology, information theory, etc. Such fields tend to assume that strong interactions between units produce new phenomena in "higher" levels that cannot be accounted for solely by reductionism. For example, it is not valuable (or currently possible) to describe a chess game or gene networks using quantum mechanics. The emergentist view of science ("More is Different", in the words of 1977 Nobel-laureate physicist Philip W. Anderson) has been inspired in its methodology by the European social sciences (Durkheim, Marx) which tend to reject methodological individualism.

Political

Elyse Amend and Darin Barney argue that while antiscience can be a descriptive label, it is often used as a rhetorical one, being effectively used to discredit one's political opponents. Thus, charges of antiscience are not necessarily warranted.

Left-wing

One expression of antiscience is the "denial of universality and... legitimisation of alternatives" and that the results of scientific findings do not always represent any underlying reality but can merely reflect the ideology of dominant groups within society. Alan Sokal states that this view associates science with the political right and is seen as a belief system that is conservative and conformist, that suppresses innovation, that resists change, and that acts dictatorially. This includes the view, for example, that science has a "bourgeois and/or Eurocentric and/or masculinist world-view".

The anti-nuclear movement, often associated with the left, has been criticized for overstating the negative effects of nuclear power, and understating the environmental costs of non-nuclear sources that can be prevented through nuclear energy. Opposition to genetically modified organisms (GMOs) has also been associated with the left.

Right-wing

The origin of antiscience thinking may be traced back to the reaction of Romanticism to the Enlightenment, a movement often referred to as the Counter-Enlightenment. Romanticism emphasizes that intuition, passion, and organic links to nature are primal values and that rational thinking is merely a product of human life. Modern right-wing antiscience includes climate change denial, rejection of evolution, and misinformation about COVID-19 vaccines. While concentrated in areas of science that are seen as motivating government action, these attitudes are strong enough to make conservatives appreciate science less in general.

Characteristics of antiscience associated with the right include the appeal to conspiracy theories to explain why scientists believe what they believe, in an attempt to undermine the confidence or power usually associated to science (e.g., in global warming conspiracy theories). In modern times, it has been argued that right-wing politics carries an anti-science tendency. While some have suggested that this is innate to either rightists or their beliefs, others have argued it is a "quirk" of a historical and political context in which scientific findings happened to challenge or appeared to challenge the worldviews of rightists rather than leftists.

Religious

Main article: Relationship between religion and science

In this context, antiscience may be considered dependent on religious, moral, and cultural arguments. For this kind of religious antiscience philosophy, science is an anti-spiritual and materialistic force that undermines traditional values, ethnic identity, and accumulated historical wisdom in favor of reason and cosmopolitanism. In particular, the traditional and ethnic values emphasized are similar to those of white supremacist Christian Identity theology. Still, similar right-wing views have been developed by radically conservative sects of Islam, Judaism, Hinduism, and Buddhism. New religious movements such as the left-wing New Age and the far-right Falun Gong thinking also criticize the scientific worldview as favouring a reductionist, atheist, or materialist philosophy.

A frequent basis of antiscientific sentiment is religious theism with literal interpretations of sacred text. Here, scientific theories that conflict with divinely inspired knowledge are regarded as flawed. Over the centuries, religious institutions have been hesitant to embrace such ideas as heliocentrism and planetary motion because they contradict the dominant interpretation of various passages of scripture. More recently, the body of creation theologies known collectively as creationism, including the teleological theory of intelligent design, has been promoted by religious theists (primarily fundamentalists) in response to the process of evolution by natural selection. One of the more extreme creation theologies, young Earth creationism, also finds itself in conflict with research in cosmology, historical geology, and the origin of life. Young Earth creationism is predominantly exclusive to fundamentalist Protestant Christianity, though it is also present in Catholicism and Judaism, albeit to a lesser extent.

Studies suggest that a belief in spirituality rather than religion may better indicate an anti-science position.

To the extent that attempts to overcome antiscience sentiments have failed, some argue that a different approach to science advocacy is needed. One such approach says that it is important to develop a more accurate understanding of those who deny science (avoiding stereotyping them as backward and uneducated) and also to attempt outreach via those who share cultural values with target audiences, such as scientists who also hold religious beliefs.

Areas

There is a cult of ignorance in the United States, and there has always been. The strain of anti-intellectualism has been a constant thread winding its way through our political and cultural life, nurtured by the false notion that democracy means that "my ignorance is just as good as your knowledge".

Isaac Asimov, "A Cult of Ignorance", Newsweek, 21 January 1980

Historically, antiscience first arose as a reaction against scientific materialism. The 18th century Enlightenment had ushered in "the ideal of a unified system of all the sciences", but there were those fearful of this notion, who "felt that constrictions of reason and science, of a single all-embracing system... were in some way constricting, an obstacle to their vision of the world, chains on their imagination or feeling". Antiscience then is a rejection of "the scientific model [or paradigm]... with its strong implication that only that which was quantifiable, or at any rate, measurable... was real". In this sense, it comprises a "critical attack upon the total claim of the new scientific method to dominate the entire field of human knowledge". However, scientific positivism (logical positivism) does not deny the reality of non-measurable phenomena, only that those phenomena should not be adequate to scientific investigation. Moreover, positivism, as a philosophical basis for the scientific method, is not consensual or even dominant in the scientific community (see philosophy of science).

Recent developments and discussions around antiscience attitudes reveal how deeply intertwined these beliefs are with social, political, and psychological factors. A study published by Ohio State News on July 11, 2022, identified four primary bases that underpin antiscience beliefs: doubts about the credibility of scientific sources, identification with groups holding antiscience attitudes, conflicts between scientific messages and personal beliefs, and discrepancies between the presentation of scientific messages and individuals' thinking styles. These factors are exacerbated in the current political climate, where ideology significantly influences people's acceptance of science, particularly on topics that have become politically polarized, such as vaccines and climate change. The politicization of science poses a significant challenge to public health and safety, particularly in managing global crises like the COVID-19 pandemic.

The following quotes explore this aspect of four major areas of antiscience: philosophy, sociology, ecology and political.

Philosophy

Philosophical objections against science are often objections about the role of reductionism. For example, in the field of psychology, "both reductionists and antireductionists accept that... non-molecular explanations may not be improved, corrected or grounded in molecular ones". Further, "epistemological antireductionism holds that, given our finite mental capacities, we would not be able to grasp the ultimate physical explanation of many complex phenomena even if we knew the laws governing their ultimate constituents". Some see antiscience as "common...in academic settings...many people see that there are problems in demarcation between science, scientism, and pseudoscience resulting in an antiscience stance. Some argue that nothing can be known for sure".

Many philosophers are "divided as to whether reduction should be a central strategy for understanding the world". However, many agree that "there are, nevertheless, reasons why we want science to discover properties and explanations other than reductive physical ones". Such issues stem "from an antireductionist worry that there is no absolute conception of reality, that is, a characterization of reality such as... science claims to provide".

Sociology

Sociologist Thomas Gieryn refers to "some sociologists who might appear to be antiscience". Some "philosophers and antiscience types", he contends, may have presented "unreal images of science that threaten the believability of scientific knowledge", or appear to have gone "too far in their antiscience deconstructions". The question often lies in how much scientists conform to the standard ideal of "communalism, universalism, disinterestedness, originality, and... skepticism". "scientists don't always conform... scientists do get passionate about pet theories; they do rely on reputation in judging a scientist's work; they do pursue fame and gain via research". Thus, they may show inherent biases in their work. "[Many] scientists are not as rational and logical as the legend would have them, nor are they as illogical or irrational as some relativists might say".

Ecology and health sphere

Within the ecological and health spheres, Levins identifies a conflict "not between science and antiscience, but rather between different pathways for science and technology; between a commodified science-for-profit and a gentle science for humane goals; between the sciences of the smallest parts and the sciences of dynamic wholes... [he] offers proposals for a more holistic, integral approach to understanding and addressing environmental issues". These beliefs are also common within the scientific community, with for example, scientists being prominent in environmental campaigns warning of environmental dangers such as ozone depletion and the greenhouse effect. In the medical sphere, patients and practitioners may choose to reject science and adopt a pseudoscientific approach to health problems. This can be both a practical and a conceptual shift and has attracted strong criticism: "therapeutic touch, a healing technique based upon the laying-on of hands, has found wide acceptance in the nursing profession despite its lack of scientific plausibility. Its acceptance is indicative of a broad antiscientific trend in nursing".

Glazer also criticises the therapists and patients, "for abandoning the biological underpinnings of nursing and for misreading philosophy in the service of an antiscientific world-view". In contrast, Brian Martin criticized Gross and Levitt by saying that "[their] basic approach is to attack constructivists for not being positivists," and that science is "presented as a unitary object, usually identified with scientific knowledge. It is portrayed as neutral and objective. Second, science is claimed to be under attack by 'antiscience' which is composed essentially of ideologues who are threats to the neutrality and objectivity that are fundamental to science. Third, a highly selective attack is made on the arguments of 'antiscience'". Such people allegedly then "routinely equate critique of scientific knowledge with hostility to science, a jump that is logically unsupportable and empirically dubious". Having then "constructed two artificial entities, a unitary 'science' and a unitary 'academic left', each reduced to epistemological essences, Gross and Levitt proceed to attack. They pick out figures in each of several areas – science studies, postmodernism, feminism, environmentalism, AIDS activism – and criticise their critiques of science".

The writings of Young serve to illustrate more antiscientific views: "The strength of the antiscience movement and of alternative technology is that their advocates have managed to retain Utopian vision while still trying to create concrete instances of it". "The real social, ideological and economic forces shaping science...[have] been opposed to the point of suppression in many quarters. Most scientists hate it and label it 'antiscience'. But it is urgently needed, because it makes science self-conscious and hopefully self-critical and accountable with respect to the forces which shape research priorities, criteria, goals".

Genetically modified foods also bring about antiscience sentiment. The general public has recently become more aware of the dangers of a poor diet, as there have been numerous studies that show that the two are inextricably linked. Anti-science dictates that science is untrustworthy, because it is never complete and always being revised, which would be a probable cause for the fear that the general public has of genetically modified foods despite scientific reassurance that such foods are safe.

Antivaccinationists rely on whatever comes to hand presenting some of their arguments as if scientific; however, a strain of antiscience is part of their approach.

Political

Political scientist Tom Nichols, from Harvard Extension School and the U.S. Naval War College, points out that skepticism towards scientific expertise has increasingly become a symbol of political identity, especially within conservative circles. This skepticism is not just a result of misinformation but also reflects a broader cultural shift towards diminishing trust in experts and authoritative sources. This trend challenges the traditional neutrality of science, positioning scientific beliefs and facts within the contentious arena of political ideology.

The COVID-19 pandemic, for example, conflicting responses to public health measures and vaccine acceptance have highlighted the extent to which science has been politicized. Such polarization suggests that for some, rejecting scientific consensus or public health guidance serves as an expression of political allegiance or skepticism towards perceived authority figures.

This politicization of science complicates efforts to address public health crises and undermines the broader social contract that underpins scientific research and its application for the public good. The challenge lies not only in combating misinformation but also in bridging ideological divides that affect public trust in science. Strategies to counteract antiscience attitudes may need to encompass more than just presenting factual information; they might also need to engage with the underlying social and psychological factors that contribute to these attitudes, fostering dialogue that acknowledges different viewpoints and seeks common ground.

Antiscience media

Major antiscience media include portals Natural News, Global Revolution TV, TruthWiki.org, TheAntiMedia.org and GoodGopher. Antiscience views have also been supported on social media by organizations known to support fake news such as the web brigades.