Explanatory gap
Encyclopedia
The explanatory gap is the claim that consciousness
and human experiences such as qualia
cannot be fully explained
just by identifying the corresponding physical (neural) processes
. Bridging this gap is known as "the hard problem
". The explanatory gap has vexed and intrigued philosophers and AI
researchers alike for decades and caused considerable debate.
To take an example of a phenomenon in which there is no gap, imagine a modern computer: as marvelous as these devices are, their behavior can be fully explained by their circuitry, and vice versa. By contrast, it is thought by some that subjective conscious experience constitutes a separate effect that demands another cause, a cause that is either outside the physical world (dualism
) or due to an as yet unknown physical phenomenon (see for instance Quantum mind
, Indirect realism).
Proponents of dualism
claim that the mind
is substantially and qualitatively different from the brain
and that the existence of something metaphysically
extra-physical is required to 'fill the gap'.
The nature of the explanatory gap has been the subject of some debate. For example, some consider it to simply be a limit on our current explanatory ability. They argue that future findings in neuroscience or future work from philosophers could close the gap. However, others have taken a stronger position and argued that the gap is a definite limit on our cognitive abilities as humans—no amount of further information will allow us to close it. There has also been no consensus regarding what metaphysical conclusions the existence of the gap provides. Those wishing to use its existence to support dualism have often taken the position that an epistemic gap—particularly if it is a definite limit on our cognitive abilities—necessarily entails a metaphysical gap.
Others, such as Joseph Levine, have wished to either remain silent on the matter or argue that no such metaphysical conclusion should be drawn. He agrees that conceivability (as used in the Zombie
and inverted spectrum
arguments) is flawed as a means of establishing metaphysical realities; but he points out that even if we come to the metaphysical conclusion that qualia are physical, they still present an explanatory problem.
However, such an epistemological or explanatory problem might indicate an underlying metaphysical issue—the non-physicality of qualia, even if not proven by conceivability arguments is far from ruled out.
Consciousness
Consciousness is a term that refers to the relationship between the mind and the world with which it interacts. It has been defined as: subjectivity, awareness, the ability to experience or to feel, wakefulness, having a sense of selfhood, and the executive control system of the mind...
and human experiences such as qualia
Qualia
Qualia , singular "quale" , from a Latin word meaning for "what sort" or "what kind," is a term used in philosophy to refer to subjective conscious experiences as 'raw feels'. Examples of qualia are the pain of a headache, the taste of wine, the experience of taking a recreational drug, or the...
cannot be fully explained
Explanation
An explanation is a set of statements constructed to describe a set of facts which clarifies the causes, context, and consequencesof those facts....
just by identifying the corresponding physical (neural) processes
Neurophysics
Neurophysics is the branch of biophysics dealing with the nervous system. It covers a wide spectrum of phenomena from molecular and cellular mechanisms to techniques to measure and influence the brain and to theories of brain function...
. Bridging this gap is known as "the hard problem
Hard problem of consciousness
The hard problem of consciousness is the problem of explaining how and why we have qualitative phenomenal experiences. David Chalmers contrasts this with the "easy problems" of explaining the ability to discriminate, integrate information, report mental states, focus attention, etc...
". The explanatory gap has vexed and intrigued philosophers and AI
Artificial intelligence
Artificial intelligence is the intelligence of machines and the branch of computer science that aims to create it. AI textbooks define the field as "the study and design of intelligent agents" where an intelligent agent is a system that perceives its environment and takes actions that maximize its...
researchers alike for decades and caused considerable debate.
To take an example of a phenomenon in which there is no gap, imagine a modern computer: as marvelous as these devices are, their behavior can be fully explained by their circuitry, and vice versa. By contrast, it is thought by some that subjective conscious experience constitutes a separate effect that demands another cause, a cause that is either outside the physical world (dualism
Dualism
Dualism denotes a state of two parts. The term 'dualism' was originally coined to denote co-eternal binary opposition, a meaning that is preserved in metaphysical and philosophical duality discourse but has been diluted in general or common usages. Dualism can refer to moral dualism, Dualism (from...
) or due to an as yet unknown physical phenomenon (see for instance Quantum mind
Quantum mind
The quantum mind or quantum consciousness hypothesis proposes that classical mechanics cannot explain consciousness, while quantum mechanical phenomena, such as quantum entanglement and superposition, may play an important part in the brain's function, and could form the basis of an explanation of...
, Indirect realism).
Proponents of dualism
Dualism
Dualism denotes a state of two parts. The term 'dualism' was originally coined to denote co-eternal binary opposition, a meaning that is preserved in metaphysical and philosophical duality discourse but has been diluted in general or common usages. Dualism can refer to moral dualism, Dualism (from...
claim that the mind
Mind
The concept of mind is understood in many different ways by many different traditions, ranging from panpsychism and animism to traditional and organized religious views, as well as secular and materialist philosophies. Most agree that minds are constituted by conscious experience and intelligent...
is substantially and qualitatively different from the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
and that the existence of something metaphysically
Metaphysics
Metaphysics is a branch of philosophy concerned with explaining the fundamental nature of being and the world, although the term is not easily defined. Traditionally, metaphysics attempts to answer two basic questions in the broadest possible terms:...
extra-physical is required to 'fill the gap'.
The nature of the explanatory gap has been the subject of some debate. For example, some consider it to simply be a limit on our current explanatory ability. They argue that future findings in neuroscience or future work from philosophers could close the gap. However, others have taken a stronger position and argued that the gap is a definite limit on our cognitive abilities as humans—no amount of further information will allow us to close it. There has also been no consensus regarding what metaphysical conclusions the existence of the gap provides. Those wishing to use its existence to support dualism have often taken the position that an epistemic gap—particularly if it is a definite limit on our cognitive abilities—necessarily entails a metaphysical gap.
Others, such as Joseph Levine, have wished to either remain silent on the matter or argue that no such metaphysical conclusion should be drawn. He agrees that conceivability (as used in the Zombie
Philosophical zombie
A philosophical zombie or p-zombie in the philosophy of mind and perception is a hypothetical being that is indistinguishable from a normal human being except in that it lacks conscious experience, qualia, or sentience...
and inverted spectrum
Inverted spectrum
Inverted spectrum is the apparent possibility of two people sharing their color vocabulary and discriminations, although the colours one sees — their qualia — are systematically different from the colours the other person sees....
arguments) is flawed as a means of establishing metaphysical realities; but he points out that even if we come to the metaphysical conclusion that qualia are physical, they still present an explanatory problem.
While I think this materialist response is right in the end, it does not suffice to put the mind-body problem to rest. Even if conceivability considerations do not establish that the mind is in fact distinct from the body, or that mental properties are metaphysically irreducible to physical properties, still they do demonstrate that we lack an explanation of the mental in terms of the physical.
However, such an epistemological or explanatory problem might indicate an underlying metaphysical issue—the non-physicality of qualia, even if not proven by conceivability arguments is far from ruled out.
In the end, we are right back where we started. The explanatory gap argument doesn't demonstrate a gap in nature, but a gap in our understanding of nature. Of course a plausible explanation for there being a gap in our understanding of nature is that there is a genuine gap in nature. But so long as we have countervailing reasons for doubting the latter, we have to look elsewhere for an explanation of the former.
See also
- BlindsightBlindsightBlindsight is a phenomenon in which people who are perceptually blind in a certain area of their visual field demonstrate some response to visual stimuli...
- CausalityCausalityCausality is the relationship between an event and a second event , where the second event is understood as a consequence of the first....
- ConsciousnessConsciousnessConsciousness is a term that refers to the relationship between the mind and the world with which it interacts. It has been defined as: subjectivity, awareness, the ability to experience or to feel, wakefulness, having a sense of selfhood, and the executive control system of the mind...
- ExplanationExplanationAn explanation is a set of statements constructed to describe a set of facts which clarifies the causes, context, and consequencesof those facts....
- Functionalism (philosophy of mind)Functionalism (philosophy of mind)Functionalism is a theory of the mind in contemporary philosophy, developed largely as an alternative to both the identity theory of mind and behaviourism. Its core idea is that mental states are constituted solely by their functional role — that is, they are causal relations to other mental...
- Hard problem of consciousnessHard problem of consciousnessThe hard problem of consciousness is the problem of explaining how and why we have qualitative phenomenal experiences. David Chalmers contrasts this with the "easy problems" of explaining the ability to discriminate, integrate information, report mental states, focus attention, etc...
- MaterialismMaterialismIn philosophy, the theory of materialism holds that the only thing that exists is matter; that all things are composed of material and all phenomena are the result of material interactions. In other words, matter is the only substance...
- MindMindThe concept of mind is understood in many different ways by many different traditions, ranging from panpsychism and animism to traditional and organized religious views, as well as secular and materialist philosophies. Most agree that minds are constituted by conscious experience and intelligent...
- Mind-body problem
- Philosophical zombiePhilosophical zombieA philosophical zombie or p-zombie in the philosophy of mind and perception is a hypothetical being that is indistinguishable from a normal human being except in that it lacks conscious experience, qualia, or sentience...
- Philosophy of mindPhilosophy of mindPhilosophy of mind is a branch of philosophy that studies the nature of the mind, mental events, mental functions, mental properties, consciousness and their relationship to the physical body, particularly the brain. The mind-body problem, i.e...
- Problem of other mindsProblem of other mindsThe problem of other minds has traditionally been regarded as an epistemological challenge raised by the skeptic. The challenge may be expressed as follows: given that I can only observe the behavior of others, how can I know that others have minds? The thought behind the question is that no matter...
- ReductionismReductionismReductionism can mean either an approach to understanding the nature of complex things by reducing them to the interactions of their parts, or to simpler or more fundamental things or a philosophical position that a complex system is nothing but the sum of its parts, and that an account of it can...
- Reverse engineeringReverse engineeringReverse engineering is the process of discovering the technological principles of a device, object, or system through analysis of its structure, function, and operation...
- SentienceSentienceSentience is the ability to feel, perceive or be conscious, or to have subjective experiences. Eighteenth century philosophers used the concept to distinguish the ability to think from the ability to feel . In modern western philosophy, sentience is the ability to have sensations or experiences...
- SolipsismSolipsismSolipsism is the philosophical idea that only one's own mind is sure to exist. The term comes from Latin solus and ipse . Solipsism as an epistemological position holds that knowledge of anything outside one's own mind is unsure. The external world and other minds cannot be known, and might not...
- Turing testTuring testThe Turing test is a test of a machine's ability to exhibit intelligent behaviour. In Turing's original illustrative example, a human judge engages in a natural language conversation with a human and a machine designed to generate performance indistinguishable from that of a human being. All...
- VitalismVitalismVitalism, as defined by the Merriam-Webster dictionary, is#a doctrine that the functions of a living organism are due to a vital principle distinct from biochemical reactions...
External links
- Joseph Levine's homepage with On-Line Articles on the problem
- Thomas Nagel, "What is it like to be a bat?" The Philosophical Review LXXXIII, 4 (October 1974): 435-50.