Anepiphenomenon (plural:epiphenomena) is a secondaryphenomenon that occurs alongside or in parallel to a primary phenomenon. The word has twosenses: one thatconnotes knowncausation and one that connotes absence of causation or reservation of judgment about it.[1][2]
In the philosophy ofcausality, an epiphenomenon is any effect of a cause apart from the effect under primary consideration. In situations in which an event of interestE is caused by (or, is said to be caused by) an eventC, which also causes (or, is said to cause) an eventF, thenF is an epiphenomenon. The problem of epiphenomena is often a counterexample to theories of causation. For example, take a simplifiedLewisian counterfactual analysis of causation that the meaning of propositions about causal relationships between two eventsA andB can be explained in terms of counterfactual conditionals of the form "ifA had not occurred thenB would not have occurred". Suppose thatC causesE and thatC has an epiphenomenonF. We then have that ifE had not occurred, thenF would not have occurred, either. But then according to the counterfactual analysis of causation, the proposition that there is a causal dependence ofF onE is true; that is, on this view,E causedF. Since this is not in line with how we ordinarily speak about causation (we would not say thatE causedF), a counterfactual analysis seems to be insufficient.[citation needed]
An epiphenomenon can be an effect of primary phenomena, but cannot affect a primary phenomenon. In thephilosophy of mind,epiphenomenalism is the view thatmental phenomena are epiphenomena in that they can be caused by physical phenomena, but cannot cause physical phenomena. In strong epiphenomenalism, epiphenomena that are mental phenomena canonly be caused by physical phenomena, not by other mental phenomena. In weak epiphenomenalism, epiphenomena that are mental phenomena can be caused by both physical phenomena and other mental phenomena, but mental phenomena cannot be the cause of any physical phenomenon.
Thephysical world operates independently of themental world in epiphenomenalism; the mental world exists as a derivativeparallel world to the physical world, affected by the physical world (and by other epiphenomena in weak epiphenomenalism), but not able to have an effect on the physical world.Instrumentalist versions of epiphenomenalism allow some mental phenomena to cause physical phenomena, when those mental phenomena can be strictly analyzable as summaries of physical phenomena, preserving causality of the physical world to be strictly analyzable by other physical phenomena.[3]
In the more general use of the word, acausal relationship between the phenomena is implied;[1][2] the epiphenomenon is a consequence of the primary phenomenon.[1][2] This is thesense that is related to the nounepiphenomenalism.
However, in medicine, this relationship is typicallynot implied, and the word is usually used in its second sense: an epiphenomenon may occur independently, and is called an epiphenomenon because it is not the primary phenomenon under study or because onlycorrelation, notcausation, is known or suspected. In this sense, saying that X isassociated with Y as an epiphenomenon is preserving an acknowledgment thatcorrelation does not imply causation.Signs,symptoms,syndromes (groups of symptoms), andrisk factors can all be epiphenomena in this sense. For example, having an increased risk of breast cancer concurrent with taking anantibiotic is an epiphenomenon. It is not the antibiotic that is causing the increased risk, but the increasedinflammation associated with the bacterial infection that prompted the taking of an antibiotic. Themetaphor of a tree is one way of helping to explain the difference to someone struggling to understand. If the infection is the root of the tree, and the inflammation is the trunk, then the cancer and the antibiotic are two branches; the antibiotic is not the trunk.
Althoughelectronics is said to be due to the influence ofelectrons, the standard approach to the study of electrical phenomena due toJames Clerk Maxwell views these particles as secondary:
InMaxwell's theory,charge andcurrent are 'epiphenomena' (secondary appearances) of underlying processes in what he termed, followingFaraday, theelectric andmagnetic fields. Indeed, Maxwell's mature theory stays completely away from microstructure of matter and from any consideration of ‘electric substance’. Instead he proposed that certain quantities should be defined at every point in space, such that relations between them (theMaxwell equations) and functions of them (such as energy functions) determine phenomena. These quantities (thefields) may depend on microphysical events, and indeed Maxwell did expend some effort in his early papers on attempting to explain qualitatively how their relations could result in mechanical motions. However, the theory explains only large-scale phenomena, and it is not necessary to have the microscopic model in mind in order to work successfully with it.[4]
Zenon Pylyshyn suggested apropositional model of cognition where people do not conceptualize ideas in images but rather in meaningful relationships. In this theory, epiphenomena refer to images because they are merely products people conceptualize from their actual thought processes.[5] Pylyshyn defends his claim by explaining that we only see images when we envision the form of an object. While visualizing objects or actions is a frequent process in our mind, it does not occur when we are considering the meaning behind an action or the non-visual properties of an object. There are many concepts we simply cannot envision.[6] Additionally, when envisioning an image, it changes based on our preconceived notions, suggesting that semantic relations precede visual images. Unfortunately, the idea of epiphenomena in propositional theory is largely subjective and notfalsifiable.[7]
The dictionary definition ofepiphenomenon at Wiktionary