Biophysics Of Consciousness: A Foundational Approach

A Foundational Approach

Roman R Poznanski, Jack A Tuszynski;Todd E Feinberg

• Publisher: WSPC
• Year: 2016
• ISBN:
  9789814644273
• Topic: Biological Sciences
• Subtopic: Science General
• Index: Biological Sciences

The problem of how the brain produces consciousness, subjectivity and "something it is like to be" remains one of the greatest challenges to a complete science of the natural world. While various scientists and philosophers approach the problem from th

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NEUROBIOLOGICAL NATURALISM

Todd E. Feinberg* and Jon Mallatt^†

*Neurology and Psychiatry, Icahn School of Medicine at Mount Sinai and Mount Sinai Beth Israel Medical Center, New York, USA;

^†School of Biological Sciences, Washington State University, Pullman, WA, USA

Abstract

Neurobiological naturalism, an extension of John Searle’s concept of biological naturalism, says primary (sensory) consciousness is a scientifically tractable problem based on natural laws although brains that possess consciousness display certain advanced neurobiological system-features. These features are complex, fast, hierarchical, system-wide, internal, and often topographically organized neuron–neuron interactions. We lay out the neurophilosophical problem of the ontological irreducibility of the subjective to the objective, describe the general and special neurobiological features of the conscious neural hierarchies in vertebrates, and then bring in evolutionary considerations to show how consciousness could have evolved in the first vertebrates. Our combined neurobiological, neuroevolutionary and neurophilosophical approach offers a solution to the hard problem of how and why physical brains can cause experiences and why consciousness and subjectivity are neurontologically irreducible.

Keywords: Consciousness; neurobiological naturalism; ontological subjectivity; hard problem; qualia; neural hierarchies; nestedness; emergence; reductionism; evolution.

1.1.Introduction

A primary philosophical obstacle to a scientific account of consciousness is the problem of ontological subjectivity; i.e., explaining how an objective and tangible brain creates experiences that have a first-person ontology. In this chapter, we review and expand a theory of neurobiological naturalism (Feinberg, 2012), that uses three domains of explanation — neurobiological, neuroevolutionary and neurophilosophical — to address different aspects of the “hard problem” of primary or sensory consciousness. We propose that by collectively considering these three overlapping approaches, sensory consciousness can be understood as the natural outcome of normal biological evolution coupled with several unique neurobiological and neurohierarchical functions.

1.2.What is Biological Naturalism?

The term “biological naturalism” was introduced by Searle (1984) as a philosophical solution to the so-called “mind–body” problem. He begins his book “The Rediscovery of the Mind” with the below explanation and definition:

“The famous mind–body problem, the source of so much controversy over the past two millennia, has a simple solution. This solution has been available to any educated person since serious work began on the brain nearly a century ago, and, in a sense, we all know it to be true. Here it is: Mental phenomena are caused by neurophysiological processes in the brain and are themselves features of the brain. To distinguish this view from the many others in the field, I call it “biological naturalism.” Mental events and processes are as much part of our biological natural history as digestion, mitosis, meiosis, or enzyme secretion” (Searle, 1992, p. 1).

According to this position, Searle (2004) asserts that conscious states are “real” (not illusory) but have a subjective first-person ontology. He argues that conscious feeling states cannot be “reduced” to their neural substrate because a third-person reduction by the observer omits this first-person ontology that needs to be explained in the first place:

“….consciousness has a first-person or subjective ontology and so cannot be reduced to anything that has third-person or objective ontology. If you try to reduce or eliminate one in favor of the other you leave something out … biological brains have a remarkable biological capacity to produce experiences, and these experiences only exist when they are felt by some human or animal agent. You can’t reduce these first-person subjective experiences to third-person phenomena for the same reason that you can’t reduce third-person phenomena to subjective experiences. You can neither reduce the neuron firings to the feelings nor the feelings to the neuron firings, because in each case you would leave out the objectivity or subjectivity that is in question” (Searle, 1997, p. 212).

A critical neuroscientific limitation of Searle’s theory of biological naturalism remains: How can we produce subjective experience from objective neural processes yet this subjectivity cannot be objectively reduced to neural processes? This apparent contradiction is the most problematic challenge to any theory that tries to “naturalize” consciousness. Indeed, were it not for this thorny issue, there would be no “famous mind–body problem,” and no “hard problem” (Chalmers, 1995; 1996) of consciousness at all.

At the heart of this enigma is the undeniable fact that although we understand consciousness to be an “emergent feature” of complex and dynamic biological systems, it remains that no other complex biological or even non-biological system poses a similar reductionist challenge. For example, while the reduction of “life” to biology and chemistry presents no philosophical barriers, consciousness displays many emergent features that are resistant to scientific reduction.

1.2.1.Reducing consciousness

Searle argues that scientific reduction involves an identity relationship in which a property A is said to be reducible to property B, if it can be shown that A “is nothing but” B. If such a “nothing but” relationship exists between two entities, then we do not need to invoke any new property to explain A over and above those principles by which we explain B.

While Searle identifies several types of scientific reduction, for our understanding of consciousness, ontological reduction is the most pertinent:

“The most important form of reduction is ontological reduction. It is the form in which objects of certain types can be shown to consist in nothing but objects of other types. For example, chairs are shown to be nothing but collections of molecules. This form is clearly important in the history of science. For example, material objects in general can be shown to be nothing but collections of molecules, genes can be shown to consist in nothing but DNA molecules” (Searle, 1992, p. 113).

Searle actually means “nothing but collections of objects and their interactions,” allowing for the interactions between parts.

One impediment to successful ontological reduction is that in complex systems novel properties may emerge from the parts of the system and their interactions. Thus explaining the relationship between emergent properties in a complex system and their scientific reduction becomes critical. We must work out if, how and why the properties emerge within the confines of the system. This is especially true when one analyzes how consciousness — an emergent property of complex brains — can be reduced to neurons and their interactions.

There are “weak” and “strong” or “radical” versions of emergence theory, which differ in how they view an emergent feature in relation to its scientific reduction (Chalmers, 2006; Feinberg, 2001a, 2001b; Kim, 2006; Van Gulick, 2001). The weak version of emergence simply states that there are higher order properties of complex systems that are novel relative to the constituent parts that create them. A commonly cited example of a weakly emergent property is the fluidity of water relative to the non-fluid properties of single water molecules. Fluidity as a property of the aggregate of water molecules poses no scientific ontological “mystery”. If one can explain all the principles of water molecules and fluid dynamics, the fluid behavior of water can be understood, making it a weakly emergent property of water molecules and their interactions.

In contrast to this weak version of emergence, the most important aspect of the strong version of emergence theory is the claim that there are emergent properties that cannot in principle ever be reduced to the component parts of a system. Dissecting such a theoretical system — if for example consciousness were a radically emergent process — would always leave something unexplained.

In biology, the most common reduction is an explanation of how whole systems are reduced to their parts and their interactions. Biological subsystems are conceived as the “material” parts of the reduction, and the interactions of these parts are processes with a time dimension. Thus, considering digestion for example, there are various constituent organs — stomach, colon, pancreas, etc. — that comprise the digestive system, and various digestive processes — enzymatic breakdown, secretion and peristalsis — that comprise the interaction of those parts. The two features combined explain how digestion occurs, and we have no difficulty reducing digestion to its parts and their interactions. In a similar fashion, with a definition of life and observations of its properties and manifestations, Darwin deduced the interactions responsible for the process of evolution, and Watson and Crick elucidated the nucleotide bonds responsible for the structure of DNA. Ultimately, we find nothing that meets that definition of life that is not reducible to biological parts and processes that create it. By Searle’s criteria, these systems display weak emergent features that can be ontologically reduced.

In neuroscience, we typically begin with a macroscopic scientific observation or a definable property (such as motor or sensory functions, an epileptic seizure, memory functions, emotions, etc.) and then attempt to explain its mechanism based upon more fundamental or known functional or anatomic properties. In this way, disorders of language or memory can be reduced to damage to particular brain regions and we understand the role these regions play in producing the function in question. Other successful ontological reductions in neuroscience and neurology include identifying how motor action is reducible to the physiology of the nerve and muscle, or determining that paralysis is reducible to injury of the motor system. There is no ontological “mystery of epilepsy” because we understand how the observable seizure can be reduced to abnormal electrical discharges of neurons in a particular brain region. In contrast, a theory that says consciousness is a radically emergent property of the brain would claim that consciousness in principle can never be reduced to the brain or explained by the laws of physics as scientists understand them.

A prototypical example of a radically emergent theory of consciousness was proposed by Nobel laureate Roger Sperry. He claimed that the mind is “more than the sum of the parts” of the material brain and that consciousness goes above and beyond the brain’s physical processes. In Sperry’s words: “…conscious phenomena are different from, more than, and not reducible to, neural events…” (Sperry, 1990, p. 383). This says consciousness does not fit Searle’s definition of ontological reduction quoted above.

Sperry viewed the mind–brain relationship in hierarchical terms and supposed that the brain’s neural elements combine in increasingly complex configurations until the mind emerges at the top of the hierarchy, and the mind cannot be reduced to the brain as the brain is currently understood by neurophysiology. According to his account, so many emergent properties and currently unknown principles must characterize the upper levels of the hierarchy that we are far from ever knowing this mysterious “brain code” (Sperry, 1983). While Sperry seems not to have embraced dualism nor said consciousness operates outside the brain or outside known laws of energy and matter, he seems to suggest that the advanced laws and properties of brains are so bey...

Table of contents

• Cover
• Halftitle
• Title
• Copyright
• Dedication
• Contents
• About the Author
• Preface
• Foreword: Addressing the Hard Problem of Consciousness John R. Searle
• Contributing Authors
• Chapter 1 Neurobiological Naturalism
• Chapter 2 The Evolutionary Origins of Consciousness
• Chapter 3 How Language Evolution Reshaped Human Consciousness
• Chapter 4 Consciousness by Surprise: A Neuropsychoanalytic Approach to the Hard Problem
• Chapter 5 Can Qualitative Biophysics Solve the Hard Problem?
• Chapter 6 The Causal Roots of Integration and the Unity of Consciousness
• Chapter 7 The Holoinformational Foundations of Consciousness
• Chapter 8 Neural Transition Dynamics and Conscious Perceptive States
• Chapter 9 The Two-Brains Hypothesis: Implications for Consciousness
• Chapter 10 The Origins of the Brain’s Endogenous Electromagnetic Field and its Relationship to Provision of Consciousness
• Chapter 11 Consciousness as a Quantum Dynamic Effect
• Chapter 12 Quantum Spin Formalism on Consciousness
• Chapter 13 The “Quantum Underground”: Where Life and Consciousness Originate
• Chapter 14 Consciousness in the Universe An Updated Review of the “Orch OR” Theory
• Index