Hierarchical Brain

An explanation of the human brain

First published 1st February 2024. This is version 1.5 published 2nd March 2024.
Three pages are not yet published: sleep, memory and an index.
Copyright © 2024 Email info@hierarchicalbrain.com

Warning - the conclusions of this website may be disturbing for some people without a stable mental disposition or with a religious conviction.

Levels of description

Levels of description is a method that can be used to describe or explain a complex thing using multiple hierarchical levels. Features that do not exist at lower levels emerge at higher levels of description. These emergent higher level features, which can be concepts and/or behaviours, qualify as being real provided they have physical form and are associated with cause and effect.

When describing or explaining the brain, this method is crucial because many important brain functions can only be described at higher levels of description. I have proposed seven levels of description, each of which has emergent concepts or behaviours. For example, coincidence detection is a low-level emergent feature, the representation of concepts in the brain is mid-level emergent feature, and “the self”, consciousness and free will are high-level emergent features.

Contents of this page
Alternative names - other names used for levels of description.
Multiple levels for complex systems - why multiple levels of description are needed.
Emergent features - a detailed description of emergent features.
Downward Causation - how a high-level feature can influence a lower-level one.
Examples - everyday examples of multiple levels of description with emergent features.
Application to the human brain - the application of levels of description to an explanation of the human brain.
References - references and footnotes.

Alternative names

Multiple levels for complex systems

Emergent features

Downward causation

Examples of different levels of description with emergent features

Application of levels of description to an explanation of the human brain

References For information on references, see structure of this website - references

  1. ^ ^ ^ Levels: Descriptive, Explanatory, and Ontological - List 2018
    doi: 10.1111/nous.12241 downloadable here or see GoogleScholar.
    This wide-ranging philosophical paper attempts to provide a formal approach to levels of description, and answers some very pertinent questions.
    Bottom of page 1 to top of page 2:
    “Although it is widely held - though by no means universally accepted - that everything in the world is the product of fundamental physical processes, it is also widely recognized that, for many scientific purposes, the right level of description or explanation is not the fundamental physical one, but a 'higher' level, which abstracts away from microphysical details.”
  2. ^ ^ Ibid. Levels: Descriptive, Explanatory, and Ontological
    (Because this is a philosophical paper, it uses lots of complicated words and phrases!)
    Page 18, second sentence under the heading “4.2 Are there emergent properties?”:
    “...a level-specific property is a property that may be instantiated by a world or object at a particular level. A higher-level property, in particular, is a property that may be instantiated by a world or object at a higher level. The notion of emergence refers to the idea that some properties may be instantiated at some higher level without being simultaneously instantiated at any lower level. Emergence is consistent with supervenience. We may say that a higher-level property is emergent if it supervenes on lower-level properties but is not generally accompanied by some corresponding ('type-equivalent') lower-level property.”
  3. ^ Ibid. Levels: Descriptive, Explanatory, and Ontological
    Page 10, last paragraph under the heading “3.3 Levels of description”: “...we use different levels of description to think and speak about the world. In fundamental physics, we describe the world in different terms than in the special sciences, such as chemistry, biology, psychology, or the social sciences. And within each of these sciences, there are debates about which level of description is appropriate for the phenomena of interest: the level of individual molecules versus that of larger aggregates in physics and chemistry, the level of the cell versus that of the organism or ecosystem in biology, the level of the brain versus that of the mind in psychology, and the level of individuals versus that of larger social entities in the social sciences. The notion of a level of explanation is closely related to that of a level of description. An explanation at a particular level - say, a macroeconomic explanation - is an explanation that uses descriptions at that level.”
  4. ^ The Consciousness Instinct - Gazzaniga published by Farrer, Straus and Giroux 2018
    Review of The Consciousness Instinct
    Page 109: “A system is complex if it has a large or diverse numbers of (a) components, (b) interconnections and interactions, and (c) resultant behaviours, some predictable, others not so much.”
  5. ^ Cognitive Neuroscience: The Biology of the Mind - Gazzaniga, Ivry and Mangun, Fourth Edition 2014 Norton & Company USA.
    Page 626, Chapter 14 under the heading “Emergence”: “A complex system is one composed of many interconnected parts, such that when they self-organize into a single system, the resulting system exhibits one or more properties not obvious from the properties of the individual parts.”
  6. ^ Neuroscience and the correct level of explanation for understanding mind - Gazzaniga 2010
    doi: 10.1016/j.tics.2010.04.005 downloadable here or see GoogleScholar.
    This paper is a very interesting even for non-scientists. It says that if an alien intelligence came to earth and visited the best neuroscience laboratories, it would find lots of scientists probing the lowest levels of working of the human brain, but not understanding the higher levels of description that are needed to explain the mind. But the idea of emergence is commonly found in other disciplines.
    End of first paragraph after the abstract, page 1:
    “ Humans seem enthralled with measurement of underlying parts but don’t realize that they have lost the plot - the understanding of mind. ... other scientists working on other complex issues have no problem with the idea of emergence. Physicists, chemists, and biologists all know about it.”
  7. ^ Emergent complex neural dynamics: the brain at the edge - Chialvo 2010
    doi: 10.1038/nphys1803 downloadable here.
    Page 2 under the heading “Emergence”: “It is accepted that almost all macroscopic phenomena - from superconductivity to gravity and from economics to photosynthesis - are the consequence of an underlying collective dynamics of their microscopic components. In neuroscience, it is the macroscopic behaviour (cognitive, emotional, motor, etc) aspect that will be ultimately understood as the emergent phenomena of an underlying neuronal collective. However, neurons being nonlinear elements, makes such understanding far from straightforward. It would be fair to say that while the problem is cast in terms most familiar to biology the solution is written in terms very familiar to physics. Let’s recall what emergent phenomena are. Emergence refers to the unexpected collective spatiotemporal patterns exhibited by large complex systems. In this context, 'unexpected' shows our inability (mathematical and otherwise) to derive such emergent patterns from the equations describing the dynamics of the individual parts of the system. ...complex systems are usually large conglomerates of interacting elements, each one exhibiting some sort of nonlinear dynamics.”
  8. ^ Ibid. Cognitive Neuroscience: The Biology of the Mind
    Page 626, Chapter 14 under the heading “Emergence”: “Emergence, then, is the arising of a new structure (previously nonexistent), with a new level of organization and new properties, that occurs during the self-organization of a complex system.”
  9. ^ Ibid. Cognitive Neuroscience: The Biology of the Mind
    Page 627, Chapter 14 under the heading “Emergence”: “...at different levels of structure, there are different types of organization with unique types of interactions governed by their own laws; and that one emerges from the other.”
  10. ^ ^ Ibid. Cognitive Neuroscience: The Biology of the Mind
    Page 627, Chapter 14 under the heading “Emergence”: “Emergence is not a mystical ghost in the machine, however. It is a ubiquitous phenomenon in nature. The job of the neuroscientist is to understand the relationship between one level of organisation and another, not to deny they exist.”
  11. ^ Emergence as a construct: History and issues - Goldstein 1999
    doi: 10.1207/s15327000em0101_4 downloadable here or see GoogleScholar.
    This article is an excellent summary of emergence, although not specifically about the brain.
    First paragraph:
    “Emergence ...refers to the arising of novel and coherent structures, patterns, and properties during the process of self-organization in complex systems.”
    The second page also has a detailed and technical list of properties of emergent phenomena.
  12. ^ Our Brains Compress Memory Files Like Computers, for Quick Access Later - Newsweek magazine January 2016
    “...researchers announced the discovery of a mechanism that compresses information we use for memory retrieval and planning future actions, and encodes that data onto a brain wave frequency that’s separate from the one our brains use to record experiences in real time. This second brain wave frequency is the one we use to play back memories much faster than they actually happened, the researchers found.”
    This Newsweek magazine summary is reporting on a paper published in the journal “Neuron”:
    Spatial Sequence Coding Differs during Slow and Fast Gamma Rhythms in the Hippocampus - Zheng, Bieri, Hsiao and Colgin 2016
    doi: 10.1016/j.neuron.2015.12.005 downloadable here or see GoogleScholar.
  13. ^ Multitasking by Brain Wave - Scientific American magazine May 2016
    “...past research suggests that when place cells encode spatial memories they produce theta waves, which operate on a relatively slow, long-wave frequency. Yet these theta oscillations do not work alone. They also contain shorter and more frequent gamma rhythms nested within them like folded accordion bellows. As each wave of electrical activity pops up at the gamma frequency, it conveys information nuggets to the interacting theta wave, effectively presenting a highlights reel relative to the longer theta wave.”
  14. ^ Conflicting emergences. Weak vs. strong emergence for the modelling of brain function - Turkheimer, Hellyer, Kehagia, Expert, Lord, Vohryzek, De Faria Dafflon, Brammer, Leech 2019
    doi: 10.1016/j.neubiorev.2019.01.023 downloadable here or see GoogleScholar.
    Page 5, fourth paragraph: “Modern Emergence can be divided into two epistemological types: strong and weak. A system is said to exhibit strong emergence when its behaviour, or the consequence of its behaviour, exceeds the limits of its constituent parts. Thus the resulting behavioural properties of the system are caused by the interaction of the different layers of that system, but they cannot be derived simply by analysing the rules and individual parts that make up the system. Weak emergence on the other hand, differs in the sense that whilst the emergent behaviour of the system is the product of interactions between its various layers, that behaviour is entirely encapsulated by the confines of the system itself, and as such, can be fully explained simply though an analysis of interactions between its elemental units.”
  15. ^ Understanding complexity in the human brain - Bassett and Gazzaniga 2011
    doi: 10.1016/j.tics.2011.03.006 downloadable here or see GoogleScholar.
    Page 204 under the heading “Emergence”: “Multiscale organization is one hallmark of complex systems and provides the structural basis for another defining phenomenon; this is the concept of emergence in which the behavior, function and/or other properties of the system (e.g. consciousness or the subjective features of consciousness - qualia) are more than the sum of the system’s parts at any particular level or across levels. In fact, such system properties can emerge from complex patterns of underlying subsystems.”
  16. ^ Ibid. Understanding complexity in the human brain
    Page 205 under the heading “Types of emergence”: “Understanding the brain depends significantly on understanding its emergent properties. What type of emergence characterizes the brain system? Are different types of emergence present between different levels of the multi scale system? When is the interaction between levels simply correlational and when is it causal? In describing emergence, several different categories are often used including substance (a baby emerges from a mother), conjunction (two parts can perform a different function than either part separately), property (wetness is not a property of a molecule but of a group of molecules), structural (three lines make a triangle), functional (letters form words) and real (a cell is alive unlike the molecules of which it is made) emergence. The mind emerges from the brain in a way that is arguably unlike any of these weak types of emergence. The mind-brain emergence therefore requires a tailored definition. Mental states emerge from physical states by strong emergence, that is in a non reducible and highly dependent manner: mental properties do not exist or change unless physical properties exist or change.”
  17. ^ Ibid. Understanding complexity in the human brain
    Page 205 under the heading “Bidirectional causation and complementarity”: “Emergence is characterized by a higher-level phenomenon stemming from a lower system level; that is, emergence is upward. However, an important property of the brain, as opposed to some other complex systems, is that emergent phenomena can feedback to lower levels, causing lower level changes through what is called downward causation. The combination of upward emergence and downward causation suggests a simple bidirectionality or more nuanced mutual complementarity that adds to the complexity of the system, and underscores the fact that the emergence of mental properties cannot be understood using fundamental reductionism.”
  18. ^ Godel, Escher, Bach - Douglas Hofstadter Penguin Books UK 1979
    This fascinating book, despite its title, is mostly about the functioning of the brain, although it covers many other subjects as well.
    See chapter 10, page 285 onwards, under the heading “Levels of Description”, for a general discussion on levels of description.
    Chapter 17, under the heading “Formal and Informal Systems” on Page 559:
    “The only way to understand such a complex system as a brain is by chunking it on higher and higher levels, and thereby losing some precision at each step.”
  19. ^ I am a strange loop - Douglas Hofstadter 2007 Basic Books or see GoogleScholar.
    Chapter 2 of this book, entitled “This Teetering Bulb of Dread and Dream” is an excellent discussion on why multiple levels of description are likely to be required to be able to explain the workings of the brain.
    Page 30 (bottom) under the heading “The Terribly Thirsty Beer Can”:
    “Dealing with brains as multi-level systems is essential if we are to make even the slightest progress in analyzing elusive mental phenomena such as perception, concepts, thinking, consciousness, 'I', free will, and so forth.”
    Page 35 (top) under the heading “Thinkodynamics and Statistical Mentalics”: “... there is not, in the brain, just one single natural upward jump, as there is in a gas, all the way from the basic constituents to the whole thing; rather, there are many way-stations in the upward passage from mentalics [low-level components of the brain] to thinkodynamics [high-level concepts such as consciousness], and this means that it is particularly hard for us to see, or even to imagine, the ground-level, neural-level explanation...”
  20. ^ Ibid. I am a strange loop
    Page 176, the last sentence of Chapter 12, entitled “Downward Causality” : “...the most efficient way to think about brains that have symbols - and for most purposes, the truest way - is to think that the microstuff inside them is pushed around by ideas and desires, rather than the reverse.”

Page last uploaded Wed Jan 31 07:25:02 2024 MST