Reductionism and Holism
Saul McLeod published 2008
The reductionism / holism debate is a controversy that raises questions about the very nature of “explanation” itself. At first sight such questions can seem difficult and abstract but in essence the two positions in this debate can be summed up in single phrases.
For the reductionist “the simple is the source of the complex”. In other words to explain a complex phenomenon (like human behavior) one needs to “reduce” it to its constituent elements. For the holist “the whole is more than the sum of the parts”.
In other words human behavior has its own properties that are not explicable in terms of the properties of the elements from which it is derived. Here we will deal with the reductionist case first.
What is Reductionism?
Reductionism is the belief that human behavior can be explained by breaking it down into smaller component parts.
Reductionists say that the best way to understand why we behave as we do is to look closely at the very simplest parts that make up our systems, and use the simplest explanations to understand how they work.
It is based on the scientific assumption of parsimony - that complex phenomena should be explained by the simplest underlying principles possible. Strong supporters of reductionism believe that behavior and mental processes should be explained within the framework of basic sciences (e.g. physiology, chemistry.... ).
However any explanation of behavior at its simplest level can be deemed reductionist. The experimental and laboratory approach in various areas of psychology (e.g. Behaviorism, biological, cognitive) reflects a reductionist position. This approach inevitably must reduce a complex behavior to a simple set of variables that offer the possibility of identifying a cause and an effect (i.e. Reductionism is a form of determinism).
Behaviorists such as Skinner explain all behavior as being a result of past learning. T he relationships between stimuli and our responses to them are the basis for all we know and how we behave. This is a reductionist view because complex behavior is being reduced to a simple stimulus and response relationship.
We might also consider the biological approach to abnormality as reductionist. The biological approach says that psychological problems can be treated like a disease and so are often treatable with drugs. Identifying the source of someone’s mental illness as an imbalance of chemicals in the brain is being reductionist.
Reductionism works at different levels. The lowest level of reductionism offers physiological explanation: these attempt to explain behavior in terms of neurochemical, genes and brain structure. At the highest sociocultural level, explanations focus on the influence on behavior of where and how we live. Between these extremes there are behavioral, cognitive and social explanations.
Supporters of a reductionist approach say that it is scientific. Breaking complicated behaviors down to small parts means that they can be scientifically tested. Then, over time, explanations based on scientific evidence will emerge. However, some would argue that the reductionist view lacks validity.
For instance, we can see how the brain responds to particular musical sounds by viewing it in a scanner, but how you feel when you hear certain pieces of music is not something a scanner can ever reveal. Just because a part of the brain that is connected with fear is activated while listening to a piece of music does not necessarily mean that you feel afraid. In this case, being reductionist is not a valid way of measuring feelings.
It is also argued that reductionist approaches do not allow us to identify why behaviors happen. For example, they can explain that running away from a large dog was made possible by our fear centers causing a stress response to better allow us to run fast, but the same reductionist view cannot say why we were afraid of the dog in the first place. In effect, by being reductionist we may be asking smaller, more specific questions and therefore not addressing the bigger issue of why we behave as we do.
It has been suggested that the usefulness of reductionist approaches depends on the purpose to which they are put. For example, investigating brain response to faces might reveal much about how we recognize faces, but this level of description should not perhaps be used to explain human attraction.
Likewise, whilst we need to understand the biology of mental disorders, we may not fully understand the disorder without taking account of social factors which influence it. Thus, whilst reductionism is useful, it can lead to incomplete explanations.
Interactionism is an alternative approach to reductionism, focusing on how different levels of analysis interact with one another. It differs from reductionism since an interactionism approach would not try to understand behavior from explanations at one level, but as an interaction between different levels.
So for example, we might better understand a mental disorder such as depression by bringing together explanations from physiological, cognitive and sociocultural levels. Such an approach might usefully explain the success of drug therapies in treating the disorder; why people with depression think differently about themselves and the world; and why depression occurs more frequently in particular populations.
Examples of Reductionism in Psychology
- Behaviorism assumes that all behavior can be reduced to simple building blocks of S-R (stimulus- response) and that complex behavior is a series of S-R chains.
- Biopsychology - Explanations for the cause of mental illnesses are often reductionist. Genetics, and neurochemical imbalances are frequently highlighted, as being the main cause of these disorders. In the case of schizophrenia for example excess production of the neurotransmitter dopamine is seen as a possible cause.
This view clearly has implications for treatment. Gender can also be reduced to biological factors (e.g. hormones). Also, language can be reduced to structures in the brain, e.g. Broca’s area, Wernicke’s area (but holism could state: influence of family, education, social class on language). Another example of biological reductionism is aggression e.g. testosterone levels.
- Structuralism One of the first approaches in psychology. Wundt tried to break conscious experiences down into its constituent (i.e. basic) parts: images, sensations and feelings.
Holism refers to any approach that emphasizes the whole rather than their constituent parts. In other words ‘the whole is greater than the sum of its parts’. Qualitative methods of the humanistic approach reflect a holistic position. Social psychology also takes a holistic view.
A holistic approach therefore suggests that there are different levels of explanation and that at each level there are “emergent properties” that cannot be reduced to the one below.
Reductionist explanations, which might work in some circumstances, are considered inappropriate to the study of human subjectivity because here the emergent property that we have to take account of is that of the “whole person”. Otherwise it makes no sense to try to understand the meaning of anything that anybody might do.
Examples of Holism in Psychology
Humanistic psychology investigates all aspects of the individual as well as the interactions between people.
Social Psychology looks at the behavior of individuals in a social context. Group behavior (e.g. conformity, de-individualization) may show characteristics that are greater than the sum of the individuals which comprise it.
- Psychoanalysis Freud adopted an interactionist approach, in that he considered that behavior was the results of dynamic interaction between id, ego and superego.
- Abnormal psychology mental disorders are often explained by an interaction of biological, psychological and environmental factors. An eclectic approach to therapy is often taken using drugs and psychotherapy.
- Perception This is were the brain understands and interprets sensory information. Visual illusions show that humans perceive more than the sum of the sensations on the retina.
Where do the main approaches in psychology stand on reductionism & holism?
The biological approach. Reductionism is often equated with physiological reductionism, offering explanations of behavior in terms of physiological mechanisms. The evolutionary approach uses evolutionary reductionism when reducing behavior to the effects of genes, as in some explanations of altruism or atypical behavior (e.g. depression).
The behaviorist approach uses a very reductionist vocabulary: stimulus, response, reinforcement, and punishment. These concepts alone are used to explain all behavior. This is called environmental reductionism because it explains behavior in terms of simple environmental factors. Behaviorists reduce the concept of the mind to behavioral components, i.e., stimulus-response links.
The cognitive approach uses the principle of machine reductionism. Information-processing approaches use the analogy of machine systems, and the simple components of such machines, as a means to describe and explain behavior. More recent computer innovations, such as the Internet and connectionist networks can be described as holist because the network behaves differently from the individual parts that go to make it up. The whole appears to be greater than the sum of its parts.
The psychodynamic approach is reductionist in so far as it relies on a basic set of structures that attempt to simplify a very complex picture (e.g. id, ego, superego, unconscious mind). On the other hand, Freud used idiographic techniques (e.g. case study or individual interview) that aim to preserve the richness of human experience rather than teasing out simple strands of behavior.
Humanism emerged as a reaction against those dehumanizing psychological perspectives that attempted to reduce behavior to a set of simple elements. Humanistic, or third force psychologists, feel that holism is the only valid approach to the complete understanding of mind and behavior. They reject reductionism in all its forms.
Their starting point is the self (our sense of personal identity) which they consider as a functioning whole. It is, in the words of Carl Rogers, an “organized, consistent set of perceptions and beliefs about oneself”. It includes an awareness of the person I am and could be. It directs our behavior in all the consciously chosen aspects of our lives and is fundamentally motivated towards achieving self-actualization.
For humanists, then, the self is the most essential and unique quality of human beings. It is what makes us what we are and is the basis of a difference between psychology and all natural science. Reductionist explanations undermine the indivisible unity of experience. They run counter to and ultimately destroy the very object of psychological enquiry. A holistic point of view is thus in humanist terms the very basis of all knowledge of the human psyche.
How to reference this article:
McLeod, S. A. (2008). Reductionism and holism. Retrieved from www.simplypsychology.org/reductionism-holism.html
Reductionism as Philosophy
Reductionism is a philosophical tenet which states that by analyzing a system to its ultimate component parts, we will be able to unravel it at deeper and deeper levels. It is the process of reducing any feature of the perceived world to its final elements with the hope of exposing all the secrets about the phenomenon.In other words, the world and its workings will be best understood - indeed can only be understood - in terms of the ultimate constituents and forces which give rise to it.
Reductionism, explicitly or implicitly, has been an important and powerful guiding principle of the scientific enterprise for a very long time. With the rise of modern science in the seventeenth century, physicists introduced certain key concepts like mass, velocity, acceleration, force, and momentum in terms of which they could describe and explain a whole range of natural phenomena.In the eighteenth century, this framework developed into the enormously powerful and fruitful field of classical mechanics. A spectacular application of classical mechanics was the discovery of the planet Neptune using only paper and pencil, i.e. from theoretical calculations alone, from the observed discrepancies in the motion of Uranus.
In the 19th century, this was extended to electromagnetic phenomena. By introducing the notions of electric charge and field, a whole new range of phenomena could be adequately explained. A significant result of this framework was the discovery, again on paper, of electromagnetic waves, a discovery which may well be regarded as the most spectacular achievement of the human mind in all of history.
Just as, in the 17th century, Descartes had reduced the entire physical universe to matter and motion, in the scientific paradigm of the 19th century, ultimately in the world there is only matter and energy in space transforming in time. In other words, every phenomenon can be reduced, in principle, to energy transformations and their impacts of material entities in the arena of space.
It was the unprecedented successes in the human capacity to explain and predict that inspired most practitioners of science to the conviction that all observed features of the phenomenal world can be ultimately reduced to atoms and molecules and the forces and principles acting on them, at least as far as the physical world was concerned.
A similar thing happened in biology also. Practically every explanatory success in biology at the micro level - from circulation and secretion to osmosis and cell structure was grounded in the principles of physics and chemistry. This prompted thinkers like Carl Ludwig and Hermann von Helmholtz to assert, not unlike La Mettrie and other thinkers in the early eighteenth century, that the entire range of phenomena pertaining to life may be understood and explained in terms of physics, chemistry, and their mechanistic framework.
Indeed, the term reductionism was coined by biologists. Its practical (i.e.results-producing) successes drew more and more scientists to this respectable school of thought within the scientific establishment. Reductionism holds that some day we can explain chemistry, biology, and even psychology through the principles of fundamental physics. This conclusion seemed obvious to some of the founders of Quantum Mechanics in the 1920s.
A climax of the reductionist quest is to be found in the so-called Standard Model and the dreams of a final TOE: Theory Of Everything, whose goal is to reduce the entire phenomenal world to one single equation: in other words, to formulate a single all-embracing principle of which the range and variety of the entire universe are but inevitable consequences.
While it is possible to break down a system into its component parts and functions, it is difficult to see how those parts and functions add up to what is actually observed. This is often illustrated with a simple example. Two atoms of hydrogen and one of oxygen are very different in aspect and properties from the water molecule that results by their combination. The bonds and structures of molecules give rise to properties that are seldom found in their component atoms.
Thus, reductionism reveals to us what are underneath everything, but says little about how they converge into something very different. In other words, reductionism reveals the being part of the world, but hardly throws any light on the becoming aspect.
This is why uncompromising reductionism is sometimes pejoratively characterized as scientism. This is why the general trend during the past few decades has been to criticize, not to say condemn reductionism as inadequate at the very least, and misleading at worst.Moreover, while reductionism may seem reasonable for the physical world, its application to the biological and the human world is not as convincing to many philosophers, theologians, and commentators on science.Alan Wallace noted that "reducing the human being to a complex of atoms governed entirely by the laws of physics seems an article of faith rather than a scientific fact."
There is an implicit assumption in some of the criticisms that scientists somehow embrace reductionism with the same zeal or unshakable conviction as other systems do about the infallibility of scriptures. It must be emphasized that reductionism has an appeal for only one reason: it has given rise to an incredibly rich harvest of significant results. Most molecular biologists and neuroscientists who write technical papers in peer-reviewed journals, and contribute to new breakthroughs in science work in their fields from this perspective. Yet, as and when other approaches arise in whatever context, if and when a non-reductionist approach turns out to be useful in providing explanations of observed phenomena, the world of science does and will adopt it.
Reductionism as a philosophy of nature may be clarified by emphasizing the difference between what Steven Weinberg called petty and grand reductionism. In the first kind, one maintains that the properties of most things can be explained in terms of the properties of their constituents. It is true that this cannot resolve all the problems of science. That is to say, not all the observed properties of complex systems can be reduced to specific properties of its simpler constituents.
However, this is not what physicists generally mean by reductionism. They mean rather the view that everything can be explained only in terms of clear laws and principles, often mathematically expressible, and that ultimately all the known laws and principles can be reduced (traced) to a minimum number of laws and principles. This may be called grand reductionism.
When one undertakes to explain any aspect of the world in a coherent and systematic way, one assumes that the world functions in coherent and systematic ways. Grand reductionism is an affirmation of this assumption. One either adopts it and goes on with the job of accounting for various aspects of observed reality, or one abandons it and does something else.In this sense, one may say that grand reductionism is at the root of all scientific explanatory endeavors.
Furthermore, science knows that there are any number of problems whose solution can be found without going to the root causes or fundamental laws. Weinberg cites the example of weather prediction where one speaks of cold fronts, warm fronts, and thunderstorms, which are useful parameters. Indeed, these are far more helpful than the molecular motion of the gases, the laws of heat exchanges, and the like which are ultimately responsible for the weather patters. Likewise, we can solve problems in projectile motion without a theory of gravitons, and we can device electrical circuits for a home without going into Maxwell's equations or quantum electrodynamics. A physician might treat a patient on the basis of the reported head-aches, stomach-aches, inability to read small letters, etc., even though all these can be traced to the basic principles and fundamental constituents that keep the body functioning.
Holism is a philosophical view which states that by considering the whole picture one gets a deeper and more complete view of a situation than by analyzing it into its component parts. What this means is that a system consisting of several recognizable parts has properties which are not present in any of is component parts. The view that a forest presents is different from that of each of its individual trees.
It takes time, effort, and careful analysis and search to find out the details of the components, that is to say, to establish the reductionist basis of a system. There is hardly a system without holistic properties. More often that not, what we experience is the holistic aspect of a system. From this perspective, the process of analysis may lead us to the reductionist components, but on the way some aspect of the whole is lost. That is why when we put back the parts together we don't always get the whole.
There are, in fact, three kinds of holism.The first is a vision, an all-embracing view of a system as a whole. The grand view of a forest as a whole is different from the view of a single tree. This kind of holism is interesting, satisfying, and meaningful. It therefore plays a part in art, literature, and philosophy.But since it rarely explains anything, we do not find in science.
One of the intrinsic features of biological systems is that they are often interconnected. No organism can live by itself, and no species is completely independent of every other. Biological holism arises from the fact that not only is the evolution of everything affected by its environment, but its very survival depends on it.
Charles Darwinstressed the importance of competition among species. Today biologists also remind us that "the structure of every organic being (organism) is related, in the most essential yet often hidden manner, to that of all other organic beings, with which it comes into competition.”In his fascinating book The Botany of Desire, Michael Pollan elaborates on how co-evolution occurs "where there is dominant interdependence between long-associated species within an ecosystem."
The other kind of holism refers to the fact that when A and B are combined, the resulting C has more properties than what each of the components bring, indeed that it may have properties which neither of them had when they were separate.We may call this non-linear holism. One of the tasks of science is to explain how this comes about.
You can take a sentence and break it up into the words and letters constituting it. But the sound and meaning that emerge from putting together those letters in that particular order are very different from the form and sound of those letters taken individually. In other words, though the whole is made up of several parts, it is not always simply equal to the sum of its parts.
This is also true in the material world. One reason we get a more complete picture from the holistic view is that in most complex systems, the whole is invariably greater than the sum of its parts. Nonlinear Holism is explained through the notion of emergence by saying that in the natural world there are two kinds of occurrences: those that arise from the properties of the individual entities, and those that arise from the combination of individual entities. In other words, there are not only consequent properties, by virtue of the properties of the constituent parts in a complex system, but also emergent properties which were not there at all in the constituent parts. Thus light is emitted as a result of the properties of atoms: electronic transition within them. On the other hand, surface tension arises because of the configuration of the atoms in a mass of water.
In this view, processes in the brain occur because of the properties of neurons.But consciousness as a phenomenon is an emergent property resulting from neural networks. Some emergent properties are the direct result of interaction between two complex entities. The tongue by itself does not experience sweetness. Sugar by itself is not sweet. Tongue plus sugar leads to sweetness which is thus an emergent property.
It is important to distinguish between emergentism and creationism. In emergentism, we get something more from something less. In creationism we get something out of nothing. In fact, emergentism as a worldview is presented as an alternative to the notion that something new can come all of a sudden in the world out of nowhere.
To explain what causes emergence, we may use the notion of information.Information is a non-physical entity which governs the behavior of complex systems. It directs the behavior of complex molecules. In the current paradigm, when we have a complex system with some non-random structure, it is said to embody some information. Information enables or directs the system to evolve or develop in specific ways. In everyday experience, information helps s find our way to a destination. At the gene level, the information in the DNA is what directs its behavior.
When we consider the behavior of matter and energy in the universe, we find that they are subject to the basic laws of physics. Another way of looking at this is to say that matter and energy act on the basis of the information that is implicit in the laws of nature. We may call this first order information.
First order information enables and directs a goodly number of things to happen.But such happenings occur in a blind and routine manner, with no purpose at all.
Next we may envisage a second order information which is at the basis of the biological world.Second order information requires long and complex molecules.The genes and biochemical processes occur from this kind of information. There can be no biological world without the DNAs and RNAs in which are embedded a whole variety of second order information. We recognize that with second order information is associated the capacity of replicating complex molecules as well as for purpose-driven behavior.
When molecules and complex structures develop with second order information, we have no longer the strict predictable course such as we find in the physical world, but possibilities for change in the original entities. One result of such changes is the emergence of brain.This very complex system becomes the source of a third order information which endows the system with the capacity for generating thoughts.There is, as far as we know, no other system in the entire universe which has this capacity.
One may say that there is information about the universe that can be gathered by systems which are capable of third order information. In other words, whereas information keeps the universe functioning, knowledge about the universe becomes a fourth order information which certain human brains are capable of unraveling.
Thus, information may be considered as a link between reductionism and holism.Information keeps the world going. First order information is at the root of the physical world, second order information is at the root of the biological world, and third order information is at the basis of the mental world. All information is ultimately tied to the matter energy substrate of the universe, and thus has a reductionist basis. On the other hand, it is fourth order information that leads to an awareness of all this, and thus reveals the interconnectedness among the countless individual cogs that keep the vast machinery running.
Review of ideas
From these considerations we may say the following:
Reductionism reveals that what seems to be smooth is in reality only an impression created by agglomeration of vast separate chunks: that there are mountains and valleys on the apparently perfect spherical lunar crystal.
Holism reveals that what seems like an unconnected heap of separate entities form a web of unity in which the constituents intertwine and form an integrated quilt. As no creature on the planet is an island unto itself, no planet is unconnected to a star, nor a star to a galaxy. Indeed every electron is entangled in some way with every other, for ultimately and in principles wave functions are non-localized spreads.
One may see there is an epistemologically significance in this:When we focus on the reductionist and separateness aspect of the phenomenal world, we get one vision of reality. When we focus on its holistic feature, we experience another vision of reality. Considering states or provinces in a country is a reductionist mode, while taking a nation as a whole is the holistic mode. Each is relevant and important in its own context.
We also recognize that the more we focus on one, the more the other becomes blurred. This complementarity relationship in the Bohr sense between reductionism and holism is illustrated in the microcosm where the particle aspect of an entity like the electron or the proton, appears as a particle in its reductionist aspect, and as a wave in its holistic mode. Thus reductionism and holism may be regarded as two modes of apprehending reality, not unlike the two sides of a coin: each meaningful and satisfying in its own way, but neither is a complete description of what obtains in the world. From this perspective reductionism and holism are somewhat like the microscope and the telescope: two powerful instruments to explore the world, one revealing the smallest constituents of what makes up the world, while the other is sweeping the cosmic grandeur and makes us aware of the unity behind the diversity.
Likewise, it is fair to say that if science makes us understand the world through its methods of analysis, religion, through its all-encompassing mode, makes us see the human experience as a grand, rich, and unifying tapestry. When science focuses uniquely on the reductionist mode it can miss the grander vision of reality. When religion misses its grand holistic vision that sees the commonalty among the peoples of the world, it is reduced to a narrowness that is both petty and dangerous.
To assert that reductionism alone leads to understanding, or that it is very mistaken in its efforts to understand would be as much a half-truth as the claim that holism is what brings us true awareness or that it is merely old-fashioned metaphysical poetry.