2. A Stratified World

There is a strong consensus amongst cosmologists that the universe appeared about 13.8 billion years ago when time and space originated, and stars and galaxies appeared in the cosmos. The idea that the world consists of structures made of smaller elements originated with the Greek thinkers. In principle, the perspective of atomism has been fully acquired by modern science although subatomic physics permeates much of current scientific and technological advances.

That the world is organised in some kind of ‘layers’ or ‘strata’, which emerge over time from previous layers consisting of smaller components is a well accepted idea. Every layer shows new properties unique to the its level, a concept of emergence that was developed in the last hundred years both from philosophers¹ and from evolutionary biologists.² This in turn led to the concept of the General Systems Theory, formalised by Ludwig von Bertalanffy.³ Each layer can also be considered a new level of complexity forming a new domain with properties distinct from those of previous layers (see table for examples). These authors are collectively regarded as ‘emergentists’.

 Table: Ideas of a stratified world.
less complex ➞ more complex

Lloyd Morgan (1921-23)	matter		life	mind	society
Alexander (1920)4	physical	chemical	life	mind		deity
Sellars (1926)5	matter		life	mind	society
Wheeler (1926-28)6	matter		life		society
Broad (1925)7	physical	chemical	life	mind
Hartmann (1935)8	inorganic	organic		psychic	culture
Bunge (1959)9	physical	chemical	biological		social
Salk (1983)10	matter		life	mind
Chaisson (2001)11	matter		life	brain	social

A stratified world raised new problems for scientific philosophy because the physical nature of each layer is not clear. Which one is more ‘real’? The atoms that compose water, or the water molecules themselves? A drop, a river, or the oceans? 

These are questions that occupy thinkers and scientists alike and, for many, they appear to have no satisfactory answer. Those who think that no matter how composite a system is, it can always be described on the basis of the elements that compose it, are described as ‘reductionists‘. According to them, the only things that really exist are the most elementary components and the derived larger structures are only appearances with no real separate existence. Interestingly Arthur Eddington¹² distinguished “primary laws” that control the behaviour of single particles while “secondary laws” are applicable to collections of atoms and molecules.

Those who think that a composite system has entirely new properties not present or implicit in the elements that compose it, are regarded as ‘holists‘. They often ascribe to the statement that the “whole is more than the sum of its parts”¹³. 

Most scientists tend to be reductionist in principle and assume that the properties of whole are already implicit in the properties of the parts but recognise the need to know the conditions in which interact. They accept that macroscopic aggregates of atoms and molecules do ‘exist’ and can be studied even when their properties are not fully understood on the bases of the properties of the composing elements. In this sense, most scientists would accept that we humans are more than a bunch of molecules. 

The contrast between reductionists and holists could be resolved by accepting in principle that all structures that emerge at a given time in the evolution of the universe, do ‘exist’ at their level, and are as ‘real’ as the underlying structures. Their reality is determined by our very ability to interact with these structures at all suitable levels. For example, fish, in addition to behaving at the kinetic level as mechanical bodies when they collide with each other, also behave as parts of a school, interacting at higher level of complexity via the sensory-motor functions of their nervous systems.

Piccinini (2022) summarises this view succinctly: “All levels are ontologically on a par; no level is more fundamental than any other. Instead, levels partially overlap with one another. Thus, understanding multilevel systems such as neurocognitive systems and what they do requires understanding all their levels and how they are mutually related. That is why, to explain complex systems, we need to study all levels: we need to study which aspects of a system explain which phenomena — that is to say, which causal powers at which levels explain which phenomena.”¹⁴

As knowledge advanced, the properties of any aggregates composed by smaller elements could be explained by interactions of the underlying elements. For example, water is the aggregation of molecules of oxygen and hydrogen with ‘watery’ properties predictable by the intrinsic properties of the two kinds of atoms that compose it and the water molecules themselves, together with knowledge of the specific environmental conditions. However, in many other cases, current knowledge of the properties of the elements is insufficient to explain the properties of the whole. 

The acceptance that emerging structures are stratified, implies a different way of describing and studying them. In multilayered structures we need to consider the interactions between levels. Indeed, the idea that existing structures represent a hierarchy of interlocking scientific descriptions of the world has been suggested.¹⁵

A measure of the degree of organisation of such a stratified system is desirable and could be identified by the number of layers that compose it. Although there is not a rigorous way to determine such number, the apparently discrete jumps between levels of complexity depend on the methods and tools used to distinguish the layers from each other. Beyond directly experiencing the world via our senses, humans have developed instruments to extend our experiences of the world in space (eg microscopes-telescopes) and time (recording instruments). In this way the range of experiences has been extended to previously non-observables structures. By extending the range of observations to the smaller and larger, shorter and longer phenomena, further levels or strata have been revealed in physical systems. In this sense, the levels or strata can be defined by the instruments used to detect and reveal them. The realisation that knowledge is highly dependent on the instruments used gave rise to the scientific philosophy of operationalism (or ‘operationalisation’) well encapsulated by the physicist Percy Williams Bridgman in his book The Logic of Modern Physics (1927)¹⁶ where he coined an operational definition of scientific knowledge. According to this perspective “…any concept is nothing more than a set of operations; the concept is synonymous with a corresponding set of operations”.

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1. For example, Nicolai Hartmann (1940): The Structure of the Real World (Der Aufbau der realen Welt). See also: https://www.ontology.co/hartmannn.htm ↩︎
2. For example, C. Lloyd Morgan (1923). Emergent Evolution. Henry Holt and Co. ↩︎
3. Ludwig von Bertalanffy (1976). General System Theory: Foundations, Development, Applications, 2nd ed. New York: George Braziller. ↩︎
4. Samuel Alexander (1920): Space, Time and Deity. See also: https://plato.stanford.edu/entries/alexander/ ↩︎
5. Roy Wood Sellars (1926): The Principles and Problems of Philosophy, New York: Macmillan.  ↩︎
6. William Morton Wheeler (1926): Emergent Evolution and the Social. Science LXIV, No. 1662, pp 433-440. Click here to download PDF file. ↩︎
7. Charlie Dunbar Broad (1925): The Mind and its Place in Nature. ↩︎
8. Nicolai Hartmann (1935): Ontologie, (4 Volumes) I: Zur Grundlegung der Ontologie, de Gruyter, Berlin-Leipzig. ↩︎
9. Mario Bunge (1959): The Place of the Causal Principle in Modern Science, 4th ed. Cambridge: Harvard University Press / New Brunswick: Transaction Publishers, 2009. ↩︎
10. Jonas Salk (1983): Anatomy of Reality: Merging of Intuition and Reason, Praeger / Convergence. ↩︎
11. Eric Chaisson (2001): Cosmic Evolution: The Rise of Complexity in Nature, Harvard University Press. ↩︎
12. Arthur Eddington (1928): The Nature of the Physical World. University of Michigan Press, 1981. Click here to download PDF file. ↩︎
13. Originally attributed to Aristotle, see https://en.wikipedia.org/wiki/Holism ↩︎
14. Gualtiero Piccinini (2022): Neurocognitive Mechanisms – A Situated, Multilevel, Mechanistic, Neurocomputational, Representational Framework for Biological Cognition, Journal of Consciousness Studies, 29 (7-8) 167-174. ↩︎
15. For example, John Henry Holland (1998): Emergence From Chaos To Order. Oxford University Press. ↩︎
16. Percy Williams Bridgman (1927): The Logic of Modern Physics. Click here to download PDF file. ↩︎

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