The eradication or abolition of suffering is the concept of using biotechnology to create a permanent absence of involuntary pain and suffering in all sentient beings.
Biology and medicine
The discovery of modern anesthesia
in the 19th century was an early breakthrough in the elimination of
pain during surgery, but acceptance was not universal. Some medical
practitioners at the time believed that anesthesia was an artificial and harmful intervention in the body's natural response to injury.
Opposition to anesthesia has since dissipated; however, the prospect of
eradicating pain raises similar concerns about interfering with life's
natural functions.
People who are naturally incapable of feeling pain or unpleasant sensations due to rare conditions like pain asymbolia or congenital insensitivity to pain have been studied to discover the biological and genetic reasons for their pain-free lives. A Scottish woman with a previously unreported genetic mutation in a FAAHpseudogene (dubbed FAAH-OUT) with resultant elevated anandamide
levels was reported in 2019 to be immune to anxiety, unable to
experience fear, and insensitive to pain. The frequent burns and cuts
she had due to her full hypoalgesia healed quicker than average.
In 1990, Medical Hypotheses published an article by L. S. Mancini on the "genetic engineering of a world without pain":
A hypothesis is presented to the
effect that everything adaptive which is achievable with a mind capable
of experiencing varying degrees of both pleasure and pain (the human condition as we know it) could be achieved with a mind capable of experiencing only varying degrees of pleasure.
The development of gene editing techniques like CRISPR has raised the prospect that "scientists can identify the causes of certain unusual people's physical superpowers and use gene editing to grant them to others." Geneticist George Church has commented on the potential future of replacing pain with a painless sensory system:
I imagine what this would be like
on another planet and in the future, and... given that imagined future,
whether we would be willing to come back to where we are now. Rather than saying whether we're willing to go forward... ask whether you're willing to come back.
Ethics and philosophy
Ethicists and philosophers in the schools of hedonism and utilitarianism, especially negative utilitarianism, have debated the merits of eradicating suffering. Transhumanist philosopher David Pearce, in The Hedonistic Imperative (1995), argues that the abolition of suffering is both technically feasible and an issue of moral urgency, stating that: "It is predicted that the world's last unpleasant experience will be a precisely dateable event."
The philosopher Nick Bostrom, director of the Future of Humanity Institute,
advises a more cautious approach due to pain's function in protecting
individuals from harm. However, Bostrom supports the core idea of using
biotechnology to get rid of "a huge amount of unnecessary and undeserved
suffering."
It has also been argued that the eradication of suffering through
biotechnology may bring about unwanted consequences, and arguments have
been made that transhumanism is not the only philosophy worthy of
consideration regarding the question of suffering — many people view
suffering as one aspect in a dualist understanding of psychological and physical functioning, without which pleasure could not exist.
Animal welfare
In 2009, Adam Shriver suggested replacing animals in factory farming with genetically engineered animals with a reduced or absent capacity to suffer and feel pain. Shriver and McConnachie argued that people who wish to improve animal welfare should support gene editing in addition to plant-based diets and cultured meat.
Katrien Devolder and Matthias Eggel proposed gene editing research animals
to remove pain and suffering. This would be an intermediate step
towards eventually stopping all experimentation on animals and adopting alternatives.
Concerning wild-animal suffering, CRISPR-based gene drives have been suggested as a cost-effective way of spreading benign alleles in sexually reproducing species.To limit gene drives spreading indefinitely (for test programmes, for example), the Sculpting Evolution group at the MIT Media Lab developed a self-exhausting form of CRISPR-based gene drive called a "daisy-chain drive."
For potential adverse effects of a gene drive, "[s]everal genetic
mechanisms for limiting or eliminating gene drives have been proposed
and/or developed, including synthetic resistance, reversal drives, and
immunizing reversal drives."
Feasibility
According to David Pearce,
eradicating suffering is technically feasible by addressing its
biological basis, as external changes cannot overcome the genetically
constrained hedonic treadmill.
Potential solutions include wireheading (direct brain stimulation for
uniform bliss), which undermines motivation and evolutionary fitness;
designer drugs, offering sustainable well-being without side effects,
though impractical for lifelong reliance; and genetic engineering,
the most promising approach. Genetic recalibration through
hyperthymia-promoting genes could raise hedonic set-points, fostering
adaptive well-being, creativity, and productivity while maintaining
responsiveness to stimuli. While scientifically achievable, this
transformation requires careful ethical and societal considerations to
navigate its profound implications.
Eliminative materialism (also called eliminativism) is a materialist position in the philosophy of mind that expresses the idea that the majority of mental states in folk psychology do not exist. Some supporters of eliminativism argue that no coherent neural basis will be found for many everyday psychological concepts such as belief or desire, since they are poorly defined. The argument is that psychological concepts of behavior and experience should be judged by how well they reduce to the biological level. Other versions entail the nonexistence of conscious mental states such as pain and visual perceptions.
Eliminativism about a class of entities is the view that the class of entities does not exist. For example, materialism tends to be eliminativist about the soul; modern chemists are eliminativist about phlogiston; modern biologists are eliminativist about élan vital; and modern physicists are eliminativist about luminiferous ether. Eliminative materialism
is the relatively new (1960s–70s) idea that certain classes of mental
entities that common sense takes for granted, such as beliefs, desires,
and the subjective sensation of pain, do not exist.The most common versions are eliminativism about propositional attitudes, as expressed by Paul and Patricia Churchland, and eliminativism about qualia (subjective interpretations about particular instances of subjective experience), as expressed by Daniel Dennett, Georges Rey, and Jacy Reese Anthis.
In the context of materialist understandings of psychology, eliminativism is the opposite of reductive materialism, arguing that mental states as conventionally understood do exist, and directly correspond to the physical state of the nervous system. An intermediate position, revisionary materialism, often argues the mental state in question will prove to be somewhat reducible to physical phenomena—with some changes needed to the commonsense concept.
Since eliminative materialism arguably claims that future
research will fail to find a neuronal basis for various mental
phenomena, it may need to wait for science to progress further. One
might question the position on these grounds, but philosophers like
Churchland argue that eliminativism is often necessary in order to open
the minds of thinkers to new evidence and better explanations. Views closely related to eliminativism include illusionism and quietism.
Overview
Various
arguments have been made for and against eliminative materialism over
the last 50 years. The view's history can be traced to David Hume, who rejected the idea of the "self" on the grounds that it was not based on any impression.
Most arguments for the view are based on the assumption that people's
commonsense view of the mind is actually an implicit theory. It is to be
compared and contrasted with other scientific theories in its
explanatory success, accuracy, and ability to predict the future.
Eliminativists argue that commonsense "folk" psychology has failed and
will eventually need to be replaced by explanations derived from
neuroscience. These philosophers therefore tend to emphasize the
importance of neuroscientific research as well as developments in artificial intelligence.
Philosophers who argue against eliminativism may take several approaches. Simulation theorists, like Robert Gordon and Alvin Goldman,
argue that folk psychology is not a theory, but depends on internal
simulation of others, and therefore is not subject to falsification in
the same way that theories are. Jerry Fodor, among others,
argues that folk psychology is, in fact, a successful (even
indispensable) theory. Another view is that eliminativism assumes the
existence of the beliefs and other entities it seeks to "eliminate" and
is thus self-refuting.
Schematic overview: Eliminativists suggest that some sciences can be reduced (blue), but that theories that are in principle irreducible will eventually be eliminated (orange).
Eliminativism maintains that the commonsense understanding of the mind is mistaken, and that neuroscience
will one day reveal that mental states talked about in everyday
discourse, using words such as "intend", "believe", "desire", and
"love", do not refer to anything real. Because of the inadequacy of
natural languages, people mistakenly think that they have such beliefs
and desires. Some eliminativists, such as Frank Jackson, claim that consciousness does not exist except as an epiphenomenon of brain function; others, such as Georges Rey, claim that the concept will eventually be eliminated as neuroscience progresses. Consciousness and folk psychology are separate issues, and it is
possible to take an eliminative stance on one but not the other. The roots of eliminativism go back to the writings of Wilfred Sellars, W.V.O. Quine, Paul Feyerabend, and Richard Rorty. The term "eliminative materialism" was first introduced by James Cornman in 1968 while describing a version of physicalism endorsed by Rorty. The later Ludwig Wittgenstein
was also an important inspiration for eliminativism, particularly with
his attack on "private objects" as "grammatical fictions".
Early eliminativists such as Rorty and Feyerabend often confused
two different notions of the sort of elimination that the term
"eliminative materialism" entailed. On the one hand, they claimed, the cognitive sciences
that will ultimately give people a correct account of the mind's
workings will not employ terms that refer to commonsense mental states
like beliefs and desires; these states will not be part of the ontology of a mature cognitive science. But critics immediately countered that this view was indistinguishable from the identity theory of mind. Quine himself wondered what exactly was so eliminative about eliminative materialism:
Is physicalism a repudiation of
mental objects after all, or a theory of them? Does it repudiate the
mental state of pain or anger in favor of its physical concomitant, or
does it identify the mental state with a state of the physical organism
(and so a state of the physical organism with the mental state)?
On the other hand, the same philosophers claimed that commonsense
mental states simply do not exist. But critics pointed out that
eliminativists could not have it both ways: either mental states exist
and will ultimately be explained in terms of lower-level
neurophysiological processes, or they do not.Modern eliminativists have much more clearly expressed the view that
mental phenomena simply do not exist and will eventually be eliminated
from people's thinking about the brain in the same way that demons have
been eliminated from people's thinking about mental illness and
psychopathology.
While it was a minority view in the 1960s, eliminative materialism gained prominence and acceptance during the 1980s. Proponents of this view, such as B.F. Skinner, often made parallels to previous superseded scientific theories (such as that of the four humours, the phlogiston theory of combustion, and the vital force
theory of life) that have all been successfully eliminated in
attempting to establish their thesis about the nature of the mental. In
these cases, science has not produced more detailed versions or
reductions of these theories, but rejected them altogether as obsolete. Radical behaviorists, such as Skinner, argued that folk psychology is already obsolete and should be replaced by descriptions of histories of reinforcement and punishment. Such views were eventually abandoned. Patricia and Paul Churchland argued that folk psychology will be gradually replaced as neuroscience matures.
Eliminativism is not only motivated by philosophical
considerations, but is also a prediction about what form future
scientific theories will take. Eliminativist philosophers therefore tend
to be concerned with data from the relevant brain and cognitive sciences.
In addition, because eliminativism is essentially predictive in nature,
different theorists can and often do predict which aspects of folk
psychology will be eliminated from folk psychological vocabulary. None
of these philosophers are eliminativists tout court.
Today, the eliminativist view is most closely associated with the Churchlands, who deny the existence of propositional attitudes (a subclass of intentional states), and with Daniel Dennett, who is generally considered an eliminativist about qualia
and phenomenal aspects of consciousness. One way to summarize the
difference between the Churchlands' view and Dennett's is that the
Churchlands are eliminativists about propositional attitudes, but reductionists about qualia, while Dennett is an anti-reductionist about propositional attitudes and an eliminativist about qualia.
More recently, Brian Tomasik and Jacy Reese Anthis have made various arguments for eliminativism. Elizabeth Irvine has argued that both science and folk psychology do not treat mental states
as having phenomenal properties so the hard problem "may not be a
genuine problem for non-philosophers (despite its overwhelming
obviousness to philosophers), and questions about consciousness may well
'shatter' into more specific questions about particular capacities." In 2022, Anthis published Consciousness Semanticism: A Precise Eliminativist Theory of Consciousness,
which asserts that "formal argumentation from precise semantics"
dissolves the hard problem because of the contradiction between
precision implied in philosophical theory and the vagueness in its
definition, which implies there is no fact of the matter for
phenomenological consciousness.
Arguments for eliminativism
Problems with folk theories
Eliminativists such as Paul and Patricia Churchland argue that folk psychology
is a fully developed but non-formalized theory of human behavior. It is
used to explain and make predictions about human mental states and
behavior. This view is often referred to as the theory of mind or just simply theory-theory, for it theorizes the existence of an unacknowledged theory. As a theory
in the scientific sense, eliminativists maintain, folk psychology must
be evaluated on the basis of its predictive power and explanatory
success as a research program for the investigation of the mind/brain.
Such eliminativists have developed different arguments to show
that folk psychology is a seriously mistaken theory and should be
abolished. They argue that folk psychology excludes from its purview or
has traditionally been mistaken about many important mental phenomena
that can and are being examined and explained by modern neuroscience.
Some examples are dreaming, consciousness, mental disorders, learning processes, and memory
abilities. Furthermore, they argue, folk psychology's development in
the last 2,500 years has not been significant and it is therefore
stagnant. The ancient Greeks
already had a folk psychology comparable to modern views. But in
contrast to this lack of development, neuroscience is rapidly
progressing and, in their view, can explain many cognitive processes that folk psychology cannot.
Folk psychology retains characteristics of now obsolete theories
or legends from the past. Ancient societies tried to explain the
physical mysteries of nature
by ascribing mental conditions to them in such statements as "the sea
is angry". Gradually, these everyday folk psychological explanations
were replaced by more efficient scientific descriptions. Today,
eliminativists argue, there is no reason not to accept an effective
scientific account of cognition. If such an explanation existed, then
there would be no need for folk-psychological explanations of behavior,
and the latter would be eliminated the same way as the mythological explanations the ancients used.
Another line of argument is the meta-induction based on what
eliminativists view as the disastrous historical record of folk theories
in general. Ancient pre-scientific "theories" of folk biology, folk
physics, and folk cosmology have all proven radically wrong.
Eliminativists argue the same in the case of folk psychology. There
seems no logical basis, to the eliminativist, to make an exception just
because folk psychology has lasted longer and is more intuitive or
instinctively plausible than other folk theories.
Indeed, the eliminativists warn, considerations of intuitive
plausibility may be precisely the result of the deeply entrenched nature
in society of folk psychology itself. It may be that people's beliefs
and other such states are as theory-laden as external perceptions and
hence that intuitions will tend to be biased in their favor.
Specific problems with folk psychology
Much of folk psychology involves the attribution of intentional states (or more specifically as a subclass, propositional attitudes).
Eliminativists point out that these states are generally ascribed
syntactic and semantic properties. An example of this is the language of thought
hypothesis, which attributes a discrete, combinatorial syntax and other
linguistic properties to these mental phenomena. Eliminativists argue
that such discrete, combinatorial characteristics have no place in
neuroscience, which speaks of action potentials, spiking frequencies,
and other continuous and distributed effects. Hence, the syntactic
structures assumed by folk psychology have no place in such a structure
as the brain.
To this there have been two responses. On the one hand, some
philosophers deny that mental states are linguistic and see this as a straw man argument. The other view is represented by those who subscribe to "a language of thought". They assert that mental states can be multiply realized and that functional characterizations are just higher-level characterizations of what happens at the physical level.
It has also been argued against folk psychology that the
intentionality of mental states like belief implies that they have
semantic qualities. Specifically, their meaning is determined by the
things they are about in the external world. This makes it difficult to
explain how they can play the causal roles they are supposed to in
cognitive processes.
In recent years, this latter argument has been fortified by the theory of connectionism.
Many connectionist models of the brain have been developed in which the
processes of language learning and other forms of representation are
highly distributed and parallel. This tends to indicate that such
discrete and semantically endowed entities as beliefs and desires are
unnecessary.
Physics eliminates intentionality
The
problem of intentionality poses a significant challenge to materialist
accounts of cognition. If thoughts are neural processes, we must explain
how specific neural networks can be "about" external objects or
concepts. We can think about Paris, for instance, but there is no clear
mechanism by which neurons can represent a city.
Traditional analogies fail to explain this phenomenon. Unlike a
photograph, neurons do not physically resemble Paris. Nor can we appeal
to conventional symbolism, as we might with a stop sign representing the
action of stopping. Such symbols derive their meaning from social
agreement and interpretation, which are not applicable to a brain's
workings. Attempts to posit a separate neural process that assigns
meaning to the "Paris neurons" merely shift the problem without
resolving it, as we then need to explain how this secondary process can
assign meaning, initiating an infinite regress.
The only way to break this regress is to postulate matter with
intrinsic meaning, independent of external interpretation. But our
current understanding of physics precludes the existence of such matter.
The fundamental particles and forces physics describes have no inherent
semantic properties that could ground intentionality. This physical
limitation presents a formidable obstacle to materialist theories of
mind that rely on neural representations. It suggests that
intentionality, as commonly understood, may be incompatible with a
purely physicalist worldview. This suggests that our folk psychological
concepts of intentional states will be eliminated in light of scientific
understanding.
Evolution eliminates intentionality
Another
argument for eliminative materialism stems from evolutionary theory.
This argument suggests that natural selection, the process shaping our
neural architecture, cannot solve the "disjunction problem", which
challenges the idea that neural states can store specific, determinate
propositional content. Natural selection, as Darwin described it, is
primarily a process of selection against rather than selection for
traits. It passively filters out traits below a certain fitness
threshold rather than actively choosing beneficial ones. This lack of
foresight or purpose in evolution becomes problematic when considering
how neural states could represent unique propositions.
The disjunction problem arises from the fact that natural
selection cannot discriminate between coextensive properties. For
example, consider two genes close together on a chromosome. One gene
might code for a beneficial trait, while the other codes for a neutral
or even harmful trait. Due to their proximity, these genes are often
inherited together, a phenomenon known as genetic linkage. Natural
selection cannot distinguish between these linked traits; it can only
act on their combined effect on the organism's fitness. Only random
processes like genetic crossover—where chromosomes exchange genetic
material during reproduction—can break these linkages. Until such a
break occurs, natural selection remains "blind" to the linked genes'
individual effects.
Eliminativists argue that if natural selection—the process
responsible for shaping our neural architecture—cannot solve the
disjunction problem, then our brains cannot store unique,
non-disjunctive propositions, as required by folk psychology. Instead,
they suggest that neural states contain inherently disjunctive or
indeterminate content. This argument leads eliminativists to reject the
notion that neural states have specific, determinate informational
content corresponding to the discrete, non-disjunctive propositions of
folk psychology. This evolutionary argument adds to the eliminativist
case that our commonsense understanding of beliefs, desires, and other
propositional attitudes is flawed and should be replaced by a
neuroscientific account that acknowledges the indeterminate nature of
neural representations.
Arguments against eliminativism
Intentionality and consciousness are identical
Some
eliminativists reject intentionality while accepting the existence of
qualia. Other eliminativists reject qualia while accepting
intentionality. Many philosophers argue that intentionality cannot exist
without consciousness and vice versa, and so any philosopher who
accepts one while rejecting the other is being inconsistent. They argue
that, to be consistent, one must accept both qualia and intentionality
or reject them both. Philosophers who argue for such a position include Philip Goff, Terence Horgan, Uriah Kriegal, and John Tienson. The philosopher Keith Frankish
accepts the existence of intentionality but holds to illusionism about
consciousness because he rejects qualia. Goff notes that beliefs are a
kind of propositional thought.
Intuitive reservations
The
thesis of eliminativism seems so obviously wrong to many critics, who
find it undeniable that people know immediately and indubitably that
they have minds, that argumentation seems unnecessary. This sort of
intuition-pumping is illustrated by asking what happens when one asks
oneself honestly if one has mental states.
Eliminativists object to such a rebuttal of their position by claiming
that intuitions often are mistaken. Analogies from the history of
science are frequently invoked to buttress this observation: it may
appear obvious that the sun travels around the earth, for example, but
this was nevertheless proved wrong. Similarly, it may appear obvious
that apart from neural events there are also mental conditions, but that
could be false.
But even if one accepts the susceptibility to error of people's
intuitions, the objection can be reformulated: if the existence of
mental conditions seems perfectly obvious and is central to our
conception of the world, then enormously strong arguments are needed to
deny their existence. Furthermore, these arguments, to be consistent,
must be formulated in a way that does not presuppose the existence of
entities like "mental states", "logical arguments", and "ideas", lest
they be self-contradictory.
Those who accept this objection say that the arguments for
eliminativism are far too weak to establish such a radical claim and
that there is thus no reason to accept eliminativism.
Self-refutation
Some philosophers, such as Paul Boghossian, have attempted to show that eliminativism is in some sense self-refuting, since the theory presupposes the existence of mental phenomena. If eliminativism is true, then eliminativists must accept an intentional property like truth,
supposing that in order to assert something one must believe it. Hence,
for eliminativism to be asserted as a thesis, the eliminativist must
believe that it is true; if so, there are beliefs, and eliminativism is
false.
Georges Rey and Michael Devitt reply to this objection by invoking deflationary semantic theories that avoid analyzing predicates
like "x is true" as expressing a real property. They are instead
construed as logical devices, so that asserting that a sentence is true
is just a quoted way of asserting the sentence itself. To say "'God
exists' is true" is just to say "God exists". This way, Rey and Devitt
argue, insofar as dispositional replacements of "claims" and
deflationary accounts of "true" are coherent, eliminativism is not
self-refuting.
Correspondence theory of truth
Several philosophers, such as the Churchlands and Alex Rosenberg, have developed a theory of structural resemblance or physical
isomorphism that could explain how neural states can instantiate truth
within the correspondence theory of truth.
Neuroscientists use the word "representation" to identify the neural
circuits' encoding of inputs from the peripheral nervous system in, for
example, the visual cortex. But they use the word without according it
any commitment to intentional content. In fact, there is an explicit
commitment to describing neural representations in terms of structures
of neural axonal discharges that are physically isomorphic to the inputs
that cause them. Suppose that this way of understanding representation
in the brain is preserved in the long-term course of research providing
an understanding of how the brain processes and stores information. Then
there will be considerable evidence that the brain is a neural network
whose physical structure is identical to the aspects of its environment
it tracks and whose representations of these features consist in this
physical isomorphism.
Experiments in the 1980s with macaques
isolated the structural resemblance between input vibrations the finger
feels, measured in cycles per second, and representations of them in
neural circuits, measured in action-potential spikes per second. This
resemblance between two easily measured variables makes it unsurprising
that they would be among the first such structural resemblances to be
discovered. Macaques and humans have the same peripheral nervous system
sensitivities and can make the same tactile discriminations. Subsequent
research into neural processing has increasingly vindicated a structural
resemblance or physical isomorphism approach to how information enters
the brain and is stored and deployed.
This isomorphism between brain and world is not a matter of some
relationship between reality and a map of reality stored in the brain.
Maps require interpretation if they are to be about what they map, and
eliminativism and neuroscience share a commitment to explaining the
appearance of aboutness by purely physical relationships between
informational states in the brain and what they "represent". The
brain-to-world relationship must be a matter of physical
isomorphism—sameness of form, outline, structure—that does not require
interpretation.
This machinery can be applied to make "sense" of eliminativism in
terms of the sentences eliminativists say or write. When we say that
eliminativism is true, that the brain does not store information in the
form of unique sentences, statements, expressing propositions or
anything like them, there is a set of neural circuits that has no
trouble coherently carrying this information. There is a possible
translation manual that will guide us back from the vocalization or
inscription eliminativists express to these circuits. These neural
structures will differ from the neural circuits of those who explicitly
reject eliminativism in ways that our translation manual will presumably
shed some light on, giving us a neurological handle on disagreement and
on the structural differences in neural circuitry, if any, between
asserting p and asserting not-p when p expresses the eliminativist
thesis.
Criticism
The
physical isomorphism approach faces indeterminacy problems. Any given
structure in the brain will be causally related to, and isomorphic in
various respects to, many different structures in external reality. But
we cannot discriminate the one it is intended to represent or that it is
supposed to be true "of". These locutions are heavy with just the
intentionality that eliminativism denies. Here is a problem of
underdetermination or holism that eliminativism shares with
intentionality-dependent theories of mind. Here, we can only invoke
pragmatic criteria for discriminating successful structural
representations—the substitution of true ones for unsuccessful ones—the
ones we used to call false.
Dennett notes that it is possible that such indeterminacy
problems remain only hypothetical, not occurring in reality. He
constructs a 4x4 "Quinian crossword puzzle" with words that must satisfy
both the across and down definitions. Since there are multiple
constraints on this puzzle, there is one solution. Thus we can think of
the brain and its relation to the external world as a very large
crossword puzzle that must satisfy exceedingly many constraints to which
there is only one possible solution. Therefore, in reality we may end
up with only one physical isomorphism between the brain and the external
world.
Pragmatic theory of truth
When
indeterminacy problems arose because the brain is physically isomorphic
to multiple structures of the external world, it was urged that a
pragmatic approach be used to resolve the problem. Another approach
argues that the pragmatic theory of truth should be used from the start to decide whether certain neural circuits store true information about the external world. Pragmatism was founded by Charles Sanders Peirce and William James, and later refined by our understanding of the philosophy of science. According to pragmatism, to say that general relativity is true is to say that it makes more accurate predictions than other theories (Newtonian mechanics, Aristotle's physics,
etc.). If computer circuits lack intentionality and do not store
information using propositions, then in what sense can computer A have
true information about the world while computer B lacks it? If the
computers were instantiated in autonomous cars,
we could test whether A or B successfully complete a cross-country road
trip. If A succeeds while B fails, the pragmatist can say that A holds
true information about the world, because A's information allows it to
make more accurate predictions (relative to B) about the world and to
move around its environment more successfully. Similarly, if brain A has
information that enables the biological organism to make more accurate
predictions about the world and helps the organism successfully move
around in the environment, then A has true information about the world.
Although not advocates of eliminativism, John Shook and Tibor Solymosi
argue that pragmatism is a promising program for understanding
advancements in neuroscience and integrating them into a philosophical
picture of the world.
Criticism
The
reason naturalism cannot be pragmatic in its epistemology starts with
its metaphysics. Science tells us that we are components of the natural
realm, indeed latecomers in the 13.8-billion-year-old universe. The
universe was not organized around our needs and abilities, and what
works for us is just a set of contingent facts that could have been
otherwise. Once we have begun discovering things about the universe that
work for us, science sets out to explain why they do. It is clear that
one explanation for why things work for us that we must rule out as
unilluminating, indeed question-begging, is that they work for us
because they work for us. If something works for us, enables us to meet
our needs and wants, there must be an explanation reflecting facts about
us and the world that produce the needs and the means to satisfy them.
The explanation of why scientific methods work for us must be a
causal explanation. It must show what facts about reality make the
methods we employ to acquire knowledge suitable for doing so. The
explanation must show that our methods work — for example, have reliable
technological application — not by coincidence, still less miracle or
accident. That means there must be some facts, events, processes that
operate in reality and brought about our pragmatic success. The demand
that success be explained is a consequence of science's epistemology. If
the truth of such explanations consists in the fact that they work for
us (as pragmatism requires), then the explanation of why our scientific
methods work is that they work. That is not a satisfying explanation.
Efficacy of folk psychology
Some philosophers argue that folk psychology is quite successful.
Simulation theorists doubt that people's understanding of the mental
can be explained in terms of a theory at all. Rather they argue that
people's understanding of others is based on internal simulations of how
they would act and respond in similar situations. Jerry Fodor
believes in folk psychology's success as a theory, because it makes for
an effective way of communication in everyday life that can be
implemented with few words. Such effectiveness could not be achieved
with complex neuroscientific terminology.
Qualia
Another problem for the eliminativist is the consideration that human beings undergo subjective experiences and hence their conscious mental states have qualia.
Since qualia are generally regarded as characteristics of mental
states, their existence does not seem compatible with eliminativism. Eliminativists such as Dennett and Rey respond by rejecting qualia.
Opponents of eliminativism see this response as problematic, since many
claim that existence of qualia is perfectly obvious. Many philosophers
consider the "elimination" of qualia implausible, if not
incomprehensible. They assert that, for instance, the existence of pain
is simply beyond denial.
Admitting that the existence of qualia seems obvious, Dennett
nevertheless holds that "qualia" is a theoretical term from an outdated
metaphysics stemming from Cartesian
intuitions. He argues that a precise analysis shows that the term is in
the long run empty and full of contradictions. Eliminativism's claim
about qualia is that there is no unbiased evidence for such experiences
when regarded as something more than propositional attitudes.
In other words, it does not deny that pain exists, but holds that it
exists independently of its effect on behavior. Influenced by
Wittgenstein's Philosophical Investigations, Dennett and Rey have defended eliminativism about qualia even when other aspects of the mental are accepted.
Quining qualia
Dennett offers philosophical thought experiments to argue that qualia do not exist. First he lists five properties of qualia:
They are "directly" or "immediately" graspable during our conscious experiences.
We are infallible about them.
They are "private": no one can directly access anyone else's qualia.
They are ineffable.
They are "intrinsic" and "simple" or "unanalyzable."
Inverted qualia
The first thought experiment Dennett uses to demonstrate that qualia lack the listed necessary properties to exist involves inverted qualia:
consider two people who have different qualia but the same external
physical behavior. But now the qualia supporter can present an
"intrapersonal" variation. Suppose a neurosurgeon works on your brain
and you discover that grass now looks red. Would this not be a case
where we could confirm the reality of qualia—by noticing how the qualia
have changed while every other aspect of our conscious experience
remains the same? Not quite, Dennett replies via the next "intuition pump"
(his term for an intuition-based thought experiment), "alternative
neurosurgery". There are two different ways the neurosurgeon might have
accomplished the inversion. First, they might have tinkered with
something "early on", so that signals from the eye when you look at
grass contain the information "red" rather than "green". This would
result in genuine qualia inversion. But they might instead have tinkered
with your memory. Here your qualia would remain the same, but your
memory would be altered so that your current green experience would
contradict your earlier memories of grass. You would still feel that the
color of grass had changed, but here the qualia have not changed, but
your memories have. Would you be able to tell which of these scenarios
is correct? No: your perceptual experience tells you that something has
changed but not whether your qualia have changed. Dennett concludes,
since (by hypothesis) the two surgical procedures can yield exactly the
same introspective effects while only one inverts the qualia, nothing in
the subject's experience can favor one hypothesis over the other. So
unless he seeks outside help, the state of his own qualia must be as
unknowable to him as the state of anyone else's. It is questionable, in
short, that we have direct, infallible access to our conscious
experience.
The experienced beer drinker
Dennett's
second thought experiment involves beer. Many people think of beer as
an acquired taste: one's first sip is often unpleasant, but one
gradually comes to enjoy it. But wait, Dennett asks—what is the "it"
here? Compare the flavor of that first taste with the flavor now. Does
the beer taste exactly the same both then and now, only now you like
that taste whereas before you disliked it? Or is it that the way beer
tastes gradually shifts—so that the taste you did not like at the
beginning is not the same taste you now like? In fact most people simply
cannot tell which is the correct analysis. But that is to give up again
on the idea that we have special and infallible access to our qualia.
Further, when forced to choose, many people feel that the second
analysis is more plausible. But then if one's reactions to an experience
are in any way constitutive of it, the experience is not so "intrinsic"
after all—and another qualia property falls.
Inverted goggles
Dennett's
third thought experiment involves inverted goggles. Scientists have
devised special eyeglasses that invert up and down for the wearer. When
you put them on, everything looks upside down. When subjects first put
them on, they can barely walk around without stumbling. But after
subjects wear them for a while, something surprising occurs. They adapt
and become able to walk around as easily as before. When you ask them
whether they adapted by re-inverting their visual field or simply got
used to walking around in an upside-down world, they cannot say. So as
in our beer-drinking case, either we simply do not have the special,
infallible access to our qualia that would allow us to distinguish the
two cases or the way the world looks to us is actually a function of how
we respond to the world—in which case qualia are not "intrinsic"
properties of experience.
Criticism
Edward
Feser objects to Dennett's position as follows. That you need to appeal
to third-person neurological evidence to determine whether your memory
of your qualia has been tampered with does not seem to show that your
qualia themselves—past or present—can be known only by appealing to that
evidence. You might still be directly aware of your qualia from the
first-person, subjective point of view even if you do not know whether
they are the same as the qualia you had yesterday—just as you might
really be aware of the article in front of you even if you do not know
whether it is the same as the article you saw yesterday. Questions about
memory do not necessarily bear on the nature of your awareness of
objects present here and now (even if they bear on what you can
justifiably claim to know about such objects), whatever those objects
happen to be. Dennett's assertion that scientific objectivity requires
appealing exclusively to third-person evidence appears mistaken. What
scientific objectivity requires is not denial of the first-person
subjective point of view but rather a means of communicating
inter-subjectively about what one can grasp only from that point of
view. Given the relational structure first-person phenomena like qualia
appear to exhibit—a structure that Carnap
devoted great effort to elucidating—such a means seems available: we
can communicate what we know about qualia in terms of their structural
relations to one another. Dennett fails to see that qualia can be
essentially subjective and still relational or non-intrinsic, and thus
communicable. This communicability ensures that claims about qualia are
epistemologically objective; that is, they can in principle be grasped
and evaluated by all competent observers even though they are claims
about phenomena that are arguably not metaphysically objective, i.e.,
about entities that exist only as grasped by a subject of experience. It
is only the former sort of objectivity that science requires. It does
not require the latter, and cannot plausibly require it if the
first-person realm of qualia is what we know better than anything else.
Illusionism
Illusionism is an active program within eliminative materialism to explain phenomenal consciousness as an illusion. It is promoted by the philosophers Daniel Dennett, Keith Frankish, and Jay Garfield, and the neuroscientist Michael Graziano. Graziano has advanced the attention schema theory of consciousness and postulates that consciousness is an illusion. According to David Chalmers,
proponents argue that once we can explain consciousness as an illusion
without the need for a realist view of consciousness, we can construct a
debunking argument against realist views of consciousness. This line of argument draws from other debunking arguments like the evolutionary debunking argument in the field of metaethics. Such arguments note that morality is explained by evolution without positing moral realism, so there is a sufficient basis to debunk moral realism.
Criticism
Illusionists
generally hold that once it is explained why people believe and say
they are conscious, the hard problem of consciousness will dissolve.
Chalmers agrees that a mechanism for these beliefs and reports can and
should be identified using the standard methods of physical science, but
disagrees that this would support illusionism, saying that the datum
illusionism fails to account for is not reports of consciousness but
rather first-person consciousness itself.
He separates consciousness from beliefs and reports about
consciousness, but holds that a fully satisfactory theory of
consciousness should explain how the two are "inextricably intertwined"
so that their alignment does not require an inexplicable coincidence. Illusionism has also been criticized by the philosopher Jesse Prinz.
For example, if a philosophical zombie were poked with a sharp
object, it would not feel any pain, but it would react exactly the way
any conscious human would. Philosophical zombie arguments are used
against forms of physicalism and in defense of the hard problem of consciousness, which is the problem of accounting in physical terms for subjective, intrinsic, first-person, what-it's-like-ness experiences. Proponents of philosophical zombie arguments, such as the philosopher David Chalmers, argue that since a philosophical zombie is by definition physically identical to a conscious person, even its logical possibility refutes physicalism. This is because it establishes the existence of conscious experience as a further fact. Philosopher Daniel Stoljar
points out that zombies need not be utterly without subjective states,
and that even a subtle psychological difference between two physically
identical people, such as how coffee tastes to them, is enough to refute
physicalism. Such arguments have been criticized by many philosophers. Some physicalists, such as Daniel Dennett, argue that philosophical zombies are logically incoherent and thus impossible, or that all humans are philosophical zombies; others, such as Christopher Hill, argue that philosophical zombies are coherent but metaphysically impossible.
History
Philosophical zombies are associated with David Chalmers, but it was philosopher Robert Kirk who first used the term "zombie" in this context, in 1974. Before that, Keith Campbell made a similar argument in his 1970 book Body and Mind, using the term "imitation man". Chalmers further developed and popularized the idea in his work.
There has been a lively debate over what the argument demonstrates. Critics who primarily argue that zombies are not conceivable include Daniel Dennett, Nigel J. T. Thomas, David Braddon-Mitchell, and Robert Kirk. Critics who assert mostly that conceivability does not entail possibility include Katalin Balog, Keith Frankish, Christopher Hill, and Stephen Yablo. Critics who question the argument's logical validity include George Bealer.
In his 2019 update to the article on philosophical zombies in the Stanford Encyclopedia of Philosophy, Kirk summed up the current state of the debate:
In spite of the fact that the
arguments on both sides have become increasingly sophisticated—or
perhaps because of it—they have not become more persuasive. The pull in
each direction remains strong.
A 2013 survey of professional philosophers by Bourget and Chalmers
found that 36% said p-zombies were conceivable but metaphysically
impossible; 23% said they were metaphysically possible; 16% said they
were inconceivable; and 25% responded "other".
In 2020, the same survey yielded almost identical results: "conceivable
but impossible" 37%, "metaphysically possible" 24%, "inconceivable"
16%, and "other" 23%.
Types of zombies
Though
philosophical zombies are widely used in thought experiments, the
detailed articulation of the concept is not always the same. P-zombies
were introduced primarily to argue against specific types of physicalism
such as materialism and behaviorism, according to which mental states
exist solely as behavior. Belief, desire, thought, consciousness, and
so on, are conceptualized as behavior (whether external behavior or
internal behavior) or tendencies towards behaviors. A p-zombie
behaviorally indistinguishable from a normal human being but lacking
conscious experiences is therefore not logically possible according to
the behaviorist,
so an appeal to the logical possibility of a p-zombie furnishes an
argument that behaviorism is false. Proponents of zombie arguments
generally accept that p-zombies are not physically possible, while opponents necessarily deny that they are metaphysically or, in some cases, even logically possible.
The unifying idea of the zombie is that of a human completely
lacking conscious experience. It is possible to distinguish various
zombie subtypes used in different thought experiments as follows:
A behavioral zombie is behaviorally indistinguishable from a human.
A neurological zombie has a human brain and is generally physiologically indistinguishable from a human.
An imperfect zombie or imp-zombie is like a p-zombie but behaves differently than a human. It is important in the context of the mind-evolution problem.
A zombie universe is identical to our world in all physical ways, except no being in it has qualia.
Zombie arguments
Zombie
arguments often support lines of reasoning that aim to show that
zombies are metaphysically possible in order to support some form of dualism—in this case the view that the world includes two kinds of substance (or perhaps two kinds of property): the mental and the physical.
In physicalism, material facts determine all other facts. Since
any fact other than that of consciousness may be held to be the same for
a p-zombie and for a normal conscious human, it follows that
physicalism must hold that p-zombies are either not possible or are the
same as normal humans.
The zombie argument is a version of general modal arguments against physicalism, such as that of Saul Kripke. Further such arguments were notably advanced in the 1970s by Thomas Nagel (1970; 1974) and Robert Kirk (1974), but the general argument was most famously developed in detail by David Chalmers in The Conscious Mind (1996).
According to Chalmers, one can coherently conceive of an entire
zombie world, a world physically indistinguishable from this one but
entirely lacking conscious experience. Since such a world is
conceivable, Chalmers claims, it is metaphysically possible, which is
all the argument requires. Chalmers writes: "Zombies are probably not
naturally possible: they probably cannot exist in our world, with its
laws of nature." The outline structure of Chalmers's version of the zombie argument is as follows:
According to physicalism, all that exists in our world (including consciousness) is physical.
Thus, if physicalism is true, a metaphysically possible world in
which all physical facts are the same as those of the actual world must
contain everything that exists in our actual world. In particular,
conscious experience must exist in such a possible world.
Chalmers argues that we can conceive of a world physically
indistinguishable from our world but in which there is no consciousness
(a zombie world). From this it follows that such a world is
metaphysically possible.
The above is a strong formulation of the zombie argument. There are
other formulations of zombie-type arguments that follow the same general
form. The premises of the general zombie argument are implied by the
premises of all the specific zombie arguments.
A general zombie argument is in part motivated by potential
disagreements between various anti-physicalist views. For example, an
anti-physicalist view can consistently assert that p-zombies are
metaphysically impossible but that inverted qualia (such as inverted spectra)
or absent qualia (partial zombiehood) are metaphysically possible.
Premises regarding inverted qualia or partial zombiehood can replace
premises regarding p-zombies to produce variations of the zombie
argument.
The metaphysical possibility of a physically indistinguishable
world with either inverted qualia or partial zombiehood implies that
physical truths do not metaphysically necessitate phenomenal truths.
To construct the general form of the zombie argument, take the
sentence P to be true if and only if the conjunct of all microphysical
truths of our world obtain, and take the sentence Q to be true if some
phenomenal truth that obtains in the actual world obtains. The general
argument goes as follows.
It is conceivable that P is true and Q is not true.
If it is conceivable that P is true and Q is not true then it is metaphysically possible that P is true and Q not true.
If it is metaphysically possible that P is true and Q is not true then physicalism is false.
Therefore, physicalism is false.
Q can be false in a possible world if any of the following obtains:
(1) there exists at least one invert relative to the actual world; (2)
there is at least one absent quale relative to the actual world; (3) all
actually conscious beings are p-zombies (all actual qualia are absent
qualia).
Another way to construe the zombie hypothesis is epistemically—as a problem of causal explanation, rather than as a problem of logical or metaphysical possibility. The "explanatory gap"—also called the "hard problem of consciousness"—is
the claim that (to date) no one has provided a convincing causal
explanation of how and why we are conscious. It is a manifestation of
the very same gap that (to date) no one has provided a convincing causal
explanation of how and why we are not zombies.
The philosophical zombie argument can also be seen through the
counterfeit bill example brought forth by Amy Kind. Kind's example
centers around a counterfeit 20-dollar bill made to be exactly like an
authentic 20-dollar bill. This is logically possible. Yet the
counterfeit bill would not have the same value.
According to Kind, in her book Philosophy of Mind: The Basics, the zombie argument can be put in this standard form from a dualist point of view:
Zombies, creatures that are
microphysically identical to conscious beings but that lack
consciousness entirely, are conceivable. If zombies are conceivable then
they are possible. Therefore, zombies are possible. If zombies are
possible, then consciousness is non-physical. Therefore, consciousness
is non-physical.
Responses
Galen Strawson
argues that it is not possible to establish the conceivability of
zombies, so the argument, lacking its first premise, can never get
going.
Chalmers has argued that zombies are conceivable, saying, "it
certainly seems that a coherent situation is described; I can discern no
contradiction in the description."
Many physicalist philosophers have argued that this scenario eliminates itself by its description;
the basis of a physicalist argument is that the world is defined
entirely by physicality; thus, a world that was physically identical
would necessarily contain consciousness, as consciousness would
necessarily be generated from any set of physical circumstances
identical to our own.
The zombie argument claims that one can tell by the power of
reason that such a "zombie scenario" is metaphysically possible.
Chalmers writes, "From the conceivability of zombies, proponents of the
argument infer their metaphysical possibility"
and argues that this inference, while not generally legitimate, is
legitimate for phenomenal concepts such as consciousness since we must
adhere to "Kripke's insight that for phenomenal concepts, there is no
gap between reference-fixers and reference (or between primary and
secondary intentions)."
That is, for phenomenal concepts, conceivability implies
possibility. According to Chalmers, whatever is logically possible is
also, in the sense relevant here, metaphysically possible.
Another response is the denial of the idea that qualia and related phenomenal notions of the mind are in the first place coherent concepts. Daniel Dennett and others argue that while consciousness and subjective experience
exist in some sense, they are not as the zombie argument proponent
claims. The experience of pain, for example, is not something that can
be stripped off a person's mental life without bringing about any
behavioral or physiological differences. Dennett believes that
consciousness is a complex series of functions and ideas. If we all can
have these experiences the idea of the p-zombie is meaningless.
Dennett argues that "when philosophers claim that zombies are
conceivable, they invariably underestimate the task of conception (or
imagination), and end up imagining something that violates their own
definition". He coined the term "zimboes"—p-zombies that have second-order beliefs—to argue that the idea of a p-zombie is incoherent; "Zimboes thinkZ they are conscious, thinkZ they have qualia, thinkZ
they suffer pains—they are just 'wrong' (according to this lamentable
tradition), in ways that neither they nor we could ever discover!".
Michael Lynch
agrees with Dennett, arguing that the zombie conceivability argument
forces us to either question whether we actually have consciousness or
accept that zombies are not possible. If zombies falsely believe they
are conscious, how can we be sure we are not zombies? We may believe we
are experiencing conscious mental states when in fact we merely hold a
false belief. Lynch thinks denying the possibility of zombies is more
reasonable than questioning our own consciousness.
Furthermore, when the concept of self is deemed to correspond to
physical reality alone (reductive physicalism), philosophical zombies
are denied by definition. When a distinction is made in one's mind
between a hypothetical zombie and oneself (assumed not to be a zombie),
the hypothetical zombie, being a subset of the concept of oneself, must
entail a deficit in observables (cognitive systems), a "seductive error" contradicting the original definition of a zombie.
Thomas Metzinger
dismisses the zombie argument as no longer relevant to the
consciousness community, calling it a weak argument that covertly relies
on the difficulty in defining "consciousness" and an "ill-defined folk
psychological umbrella term".
According to verificationism,
for words to have meaning, their use must be open to public
verification. Since it is assumed that we can talk about our qualia, the
existence of zombies is impossible.
Artificial intelligence researcher Marvin Minsky
saw the argument as circular. The proposition of the possibility of
something physically identical to a human but without subjective
experience assumes that the physical characteristics of humans are not
what produces those experiences, which is exactly what the argument
claims to prove.
Richard Brown agrees that the zombie argument is circular. To show this, he proposes "zoombies", which are creatures nonphysically
identical to people in every way and lacking phenomenal consciousness.
If zoombies existed, they would refute dualism because they would show
that consciousness is indeed physical. Paralleling the argument from
Chalmers: It is conceivable that zoombies exist, so it is possible they
exist, so dualism is false. Given the symmetry between the zombie and
zoombie arguments, we cannot arbitrate the physicalism/dualism question a priori.
Similarly, Gualtiero Piccinini
argues that the zombie conceivability argument is circular. Piccinini
questions whether the possible worlds where zombies exist are accessible
from our world. If physicalism is true in our world, then physicalism
is one of the relevant facts about our world for determining whether a
possible zombie world is accessible from our world. Therefore, asking
whether zombies are metaphysically possible in our world is equivalent
to asking whether physicalism is true in our world.
Stephen Yablo's (1998) response is to provide an error theory
to account for the intuition that zombies are possible. Notions of what
counts as physical and as physically possible change over time so conceptual analysis
is not reliable here. Yablo says he is "braced for the information that
is going to make zombies inconceivable, even though I have no real idea
what form the information is going to take."
The zombie argument is difficult to assess because it brings to
light fundamental disagreements about the method and scope of philosophy
itself and the nature and abilities of conceptual analysis. Proponents
of the zombie argument may think that conceptual analysis is a central
part of (if not the only part of) philosophy and that it certainly can
do a great deal of philosophical work. But others, such as Dennett, Paul Churchland and W.V.O. Quine, have fundamentally different views. For this reason, discussion of the zombie argument remains vigorous in philosophy.
Some accept modal
reasoning in general but deny it in the zombie case. Christopher S.
Hill and Brian P. McLaughlin suggest that the zombie thought experiment
combines imagination of a "sympathetic" nature (putting oneself in a
phenomenal state) and a "perceptual" nature (imagining becoming aware of
something in the outside world). Each type of imagination may work on
its own but not work when used at the same time. Hence Chalmers's
argument need not go through.
Moreover, while Chalmers defuses criticisms of the view that
conceivability can tell us about possibility, he provides no positive
defense of the principle. As an analogy, the generalized continuum hypothesis
has no known counterexamples, but this does not mean we must accept it.
Indeed, according to Hill and McLaughlin, the fact that Chalmers
concludes we have epiphenomenal mental states that do not cause our physical behavior seems to be a reason to reject his principle.
Related thought experiments
Frank Jackson's knowledge argument
is based around a hypothetical scientist, Mary, who is forced to view
the world through a black-and-white television screen in a black and
white room. Mary is a brilliant scientist who knows everything about the
neurobiology of vision. Even though she knows everything about color
and its perception (e.g. what combination of wavelengths makes the sky
seem blue), she has never seen color. If Mary were released from this
room and experienced color for the first time, would she learn anything
new? Jackson initially believed this supported epiphenomenalism (mental phenomena are the effects, but not the causes, of physical phenomena) but later changed his view to physicalism, suggesting that Mary is simply discovering a new way for her brain to represent qualities that exist in the world.
Swampman is an imaginary character introduced by Donald Davidson.
If Davidson goes hiking in a swamp and is struck and killed by a
lightning bolt while nearby another lightning bolt spontaneously
rearranges a bunch of molecules so that, entirely by coincidence, they
take on exactly the same form that Davidson's body had at the moment of
his untimely death, then this being, "Swampman", has a brain
structurally identical to Davidson's and will thus presumably behave
exactly like Davidson. He will return to Davidson's office and write the
same essays he would have written, recognize all of his friends and
family, and so forth.
John Searle's Chinese room
argument deals with the nature of artificial intelligence: it imagines a
room in which a conversation is held by means of written Chinese
characters that the subject cannot actually read, but is able to
manipulate meaningfully using a set of algorithms. Searle holds that a
program cannot give a computer a "mind" or "understanding", regardless
of how intelligently it may make it behave. Stevan Harnad argues that Searle's critique is really meant to target functionalism and computationalism, and to establish neuroscience as the only correct way to understand the mind.
Physicist Adam Brown has suggested constructing a type of philosophical zombie using counterfactual quantum computation,
a technique in which a computer is placed into a superposition of
running and not running. If the program being executed is a brain
simulation, and if one makes the further assumption that brain
simulations are conscious, then the simulation can have the same output
as a conscious system, yet not be conscious.
Ethical questions around whether crustaceans, such as lobsters, are sentient and can experience pain, have been a topic of much debate. Nowadays, lobsters are usually considered sentient.
The ethics of uncertain sentience refers to questions surrounding the treatment of and moral obligations towards individuals whose sentience—the
capacity to subjectively sense and feel—and resulting ability to
experience pain is uncertain; the topic has been particularly discussed
within the field of animal ethics, with the precautionary principle frequently invoked in response.
Views
Animal ethics
David Foster Wallace in his 2005 essay "Consider the Lobster" investigated the potential sentience and capacity of crustaceans to experience pain and the resulting ethical implications of eating them.
In 2014, the philosopher Robert C. Jones explored the ethical question
that Wallace raised, arguing that "[e]ven if one remains skeptical of
crustacean sentience, when it comes to issues of welfare it would be
most prudent to employ the precautionary principle regarding our
treatment of these animals, erring on the side of caution". Maximilian Padden Elder takes a similar view regarding the capacity for fishes to feel pain, arguing that the "precautionary principle is the moral ethic one ought to adopt in the face of uncertainty".
In the 2015 essay "Reconsider the Lobster", Jeff Sebo quotes Wallace's discussion of the difficulty of establishing whether an animal can experience pain.
Sebo calls the question of how to treat individuals of uncertain
sentience, the "sentience problem" and argues that this problem which
"Wallace raises deserves much more philosophical attention than it
currently receives." Sebo asserts that there are two motivating assumptions behind the problem: "sentientism about moral status"—the idea that if an individual is
sentient, then they deserve moral consideration—and "uncertainty about
other minds", which refers to scientific and philosophical uncertainty
about which individuals are sentient.
In response to the problem, Sebo lays out three different
potential approaches: the incautionary principle, which postulates that
in cases of uncertainty about sentience it is morally permissible to
treat individuals as if they are not sentient; the precautionary
principle, which suggests that in such cases we have a moral obligation
to treat them as if they are sentient; and the expected value principle,
which asserts that we are "morally required to multiply our credence
that they are by the amount of moral value they would have if they were,
and to treat the product of this equation as the amount of moral value
that they actually have". Sebo advocates for the latter position.
A modular cricket farm. The sentience of crickets is uncertain, but the number of animals per meal is particularly high.
Jonathan Birch,
in answer to the question surrounding animal sentience, advocates for a
practical framework based on the precautionary principle, arguing that
the framework aligns well with conventional practices in animal welfare science.
Simon Knutsson and Christian Munthe argue that from the perspective of virtue ethics,
that when it comes to animals of uncertain sentience, such as "fish,
invertebrates such as crustaceans, snails and insects", that it is a
"requirement of a morally decent (or virtuous) person that she at least
pays attention to and is cautious regarding the possibly morally
relevant aspects of such animals".
Shelley A. Adamo argues that although the precautionary principle
in relation to potential invertebrate sentience is the safest option,
that it's not cost-free, as thoughtless legislation employed following
the precautionary principle could be economically costly and that, as a
result, we should be cautious about adopting it.
Environmental ethics
Kai Chan advocates for an environmental ethic, which is a form of ethical extensionism
applied to all living beings because "there is a non-zero probability
of sentience and consciousness" and that "we cannot justify excluding
beings from consideration on the basis of uncertainty of their
sentience".
Nick Bostrom and Eliezer Yudkowsky argue that if an artificial intelligence is sentient,
then it is wrong to inflict it unnecessary pain, in the same way that
it is wrong to inflict pain on an animal, unless there are "sufficiently
strong morally overriding reasons to do so".
They also advocate for the "Principle of Substrate Non-Discrimination",
which asserts: "If two beings have the same functionality and the same
conscious experience, and differ only in the substrate of their
implementation, then they have the same moral status."
Soenke Ziesche and Roman Yampolskiy coined the term "AI welfare" and outlined the new field of AI welfare science, which is derived from animal welfare science.
Adam J. Shriver argues for "precise, precautionary, and probabilistic
approaches to sentience" and asserts that the evidence provided by
neuroscience has differing relevance to each; he concludes that basic
protections for animals should be guided by the precautionary principle
and that although neuroscientific evidence in certain instances is not
necessary to indicate that individuals of certain species require
protections, "ongoing search for the neural correlates of sentience must
be pursued in order to avoid harms that occur from mistaken accounts."
