Layers of Reality: Reductionism and Emergence
What is Reductionism?
Reductionism, broadly speaking, is the view that complex things can be understood, explained, or accounted for in terms of simpler or more fundamental things; that more complex things are composed of and can be understood through their simpler constituent parts. The whole is nothing but its parts.
Reductionism is usually defined methodologically. But there are 3 types.
- Methodological Reductionism: we can understand things by looking at the parts that make it up
- Ontological Reductionism: things are made up of nothing but their parts
- Theoretical Reductionism: higher level theories and knowledge of about things are ultimately derived from lower level ones
Differences between them?
They all sound similar and the difference is subtle. Methodological reductionism can be thought as reductionism in practice or by studying and researching. It just claims we can learn about things by looking at what it comprises and the interactions of the constituents.
That implies that the things we’re studying are entirely made up of its parts, whether the body being made of its organs, organs of cells, and eventually atoms and more. This is what Ontological Reductionism claims. Ontological and Methodological are tightly coupled but one could argue that the whole is more than its parts, which is where Methodological Reductionist would not be a Ontological Reductionist, perhaps in pluralism or something else.
If Methodological is in practice or about strategies and Ontological is metaphysical, what exists, then Theoretical Reductionism is epistemological, about explanations and how we can understand it. Again, Ontological and epistemological are tightly coupled, but the difference is Ontological talks about what is and epistemological talks about how we come to know and explain it, regardless of what it actually is. Epistemological reducibility can imply its ontological reducibility, but it does not always. We could explain reductionally but in reality there could be a piece missing or it could exist in a totally different form, whether pluralistically or whatever.
Experiments can be done with Methodological Reductionism, to gain the knowledge for Ontological Reductionism, and perhaps come to the conclusion that it is Ontologically reducible.
So what?
At first this may not sound exciting or revolutionary but this is fundamentally foundational, basal, and so has wide reaching implications. It describes the world at such a low level it affects everything, metaphysically, epistemologically, and practically.
If everything is ultimately reducible to its parts, and those parts are themselves reducible to smaller parts, eventually down to atoms, subatomic particles, quantum fluctuations, or whatever the lowest level may be, then nothing is really as it appears and is really an illusion. You are nothing but a collection of atoms. Life is nothing but a continuous pattern of certain type atomic interactions. (Start of 😱) Consciousness is nothing but that continuous pattern of interactions reaching a certain level of complexity. Freewill is nothing but that continuous pattern of interactions reaching a certain level of complexity deciding that its actions mean something. Morality is not but evolutionary stable strategies we came up with using our free will.
That does go to say that you, life, consciousness, or free will does not exist. It just means that it is made of parts and those parts may look like nothing like what makes up the whole, at least at first, and we have to abstract and zoom out from the parts to view the whole as we normally do.
Reductionism does not imply that higher-level things are unreal. It implies that they are not fundamental, real ≠ fundamental.
Reductionism and Science
Most of science can be said to have its foundations in Reductionism, at least Methodologically and usually Theoretically and sometimes Ontologically.
To learn about the world, science exams what makes it up and then explains it. Biology goes from organism to molecules, chemistry picks up molecules to atoms, and physics continues from atoms. And it doesn’t have to cross fields. Behavior of a population is done by collecting data from individuals, a chemical reaction is looked at from one electron transfer to another, and orbits of stellar systems are predicted from each of its celestial bodies.
Reductionism is a powerful force and approach and there seems no bound to its explained power. Not to say we should always zoom in. Holism has its definite applications where the property we are studying only exists in a whole or even collection of wholes (which itself is a while) like in a population of animals.
What is Emergence?
Emergence, broadly speaking, is the idea that parts and their interactions make up the whole; the pieces comprise the whole; simple things can make something much more complex.
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There are two types though. Sometimes described ontologically as:
- Weak Emergence: higher-level property arises from lower-level parts but does not constitute a fundamentally new kind of thing.
- Strong Emergence: higher-level property arises from lower-level parts but is genuinely new and cannot be fully explained or reduced to those lower-level parts.
Sometimes the definition is given in terms of epistemology:
- Weak Emergence: we can in theory come to understand all the properties complex things by looking at the simples things that make it up (because no new properties emerges)
- Strong Emergence: we can never come to fully understand all the properties complex things by looking at the simples things that make it up (because new properties only emerges when you combine them)
The epistemological definition can obscure the ontological implication.
The Difference is Important
Weak emergence claims there are no ‘new’ properties, strong emergence claims something ‘new’ does come out of the whole. They may seem very similar, and they are mostly, but the slight difference of something ‘new’ emerging is all the difference.
Weak emergence says that a higher-level property can arise from the organization and interaction of simpler parts without anything fundamentally new being added to reality. The property may be surprising, difficult to predict, or practically impossible to derive without studying the system at the higher level, but in principle it does not require new entities, forces, or fundamental laws. The whole can therefore have properties that its individual parts do not have on their own while still being completely grounded in the parts and their interactions.
Strong emergence makes the stronger claim that some higher-level properties are genuinely novel in a way that cannot be fully reduced to the lower level. The higher-level property is not merely difficult to predict or describe; it has some feature that is not exhausted by the lower-level facts. Depending on the theory, this might mean that higher-level properties require fundamentally new laws, have novel causal powers, or cannot even in principle be completely explained in terms of the lower-level description.
This is also why weak emergence is generally much more compatible with reductionism and physicalism. Nothing fundamentally new has been added; the higher-level phenomenon is still fully grounded in the lower-level reality. Strong emergence is more controversial because, if genuinely novel properties or causal powers exist at higher levels, we have to explain what those properties are and how they relate to the lower-level world.
That does not automatically make strong emergence mystical, pluralistic, or non-physical, however. A strong emergentist could still believe that there is only one physical reality. The disagreement is specifically about whether everything that exists and everything that happens at higher levels is fully accounted for by the lower-level description.
The problem is when people use them interchangeably. Strong emergence implies something totally different than weak emergence.
The classic example is a wave. A water wave is composed of enormous numbers of H₂O molecules. A wave cannot exist with just one or even a few water molecules. It is an emergent phenomenon that arises when a sufficiently large number of molecules interact in a particular organized way. Does a ‘new’ property emerge? Weak emergence says ‘no’, the phenomena of a wave can completely be understood and predicted from the polar nature of water molecules or whatever it may be, whether in hindsight or not. That is not much of a debate but where the contention lies is in higher-level phenomena.
Emergence and Higher-level Phenomenas
Take for example life, consciousness, free will, or ethics.
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Layers of Reductionism and Emergence
Emergence then is the counterpart to Reductionism. If reductionism goes down, emergence goes up.
Emergence↑ and Reductionism↓, emerge↑ and reduce↓, explains↑ and is explained by↓. Levels. Call it Abstractionism
Composition → supervenience → reduction → emergence somewhere?
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Not done!
