Cutting the risk of dying in half. The new study, led by thoracic medical oncologist Leena Gandhi, MD, PhD, associate professor of medicine and director of the thoracic medical oncology program at NYU’s Perlmutter Cancer Center, shows that treating lung cancer by a combination of immunotherapy with Merck’s Keytruda (aka pembrolizumab) and chemotherapy is more effective than chemotherapy alone, according to a statement by NYU Langone Health.
The combination cut in half the risk of dying or having the cancer worsen, compared to chemo alone, after nearly one year, the Associated Press reported in The New York Times.
“The results are expected to quickly set a new standard of care for
about 70,000 patients each year in the United States whose lung cancer
has already spread by the time it’s found,” the AP stated.
“Another study found that an immunotherapy combo — the Bristol-Myers
Squibb drugs Opdivo and Yervoy — worked better than chemo for delaying
the time until cancer worsened in advanced lung cancer patients whose
tumors have many gene flaws, as nearly half do. But the benefit lasted
less than two months on average and it’s too soon to know if the combo
improves overall survival, as Keytruda did.”
Micrograph of a squamous carcinoma, a type of non-small-cell lung cancer (credit: Wikipedia)
Removing a cloak. All three of these “checkpoint inhibitor” treatments remove a “cloak” that some cancer cells have that hides the cancer cells from the immune system.
These immune-therapy treatments — which are administered through IVs
and cost about $12,500 a month — worked for only about half of patients.
But that’s far better than chemo alone has done in the past, notes the
AP.
The American Cancer Society estimates that in 2018, there will be about 234,030 new cases of lung cancer in the U.S and about 154,050 deaths from lung cancer.
The
saying holds that the world is supported by a chain of increasingly
large turtles. Beneath each turtle is yet another: it is "turtles all
the way down".
"Turtles all the way down" is an expression of the problem of infinite regress. The saying alludes to the mythological idea of a World Turtle
that supports the earth on its back. It suggests that this turtle rests
on the back of an even larger turtle, which itself is part of a column
of increasingly large turtles that continues indefinitely (i.e. "turtles all the way down").
The exact origin of the phrase is uncertain. In the form "rocks all the way down", the saying appears as early as 1838.[1] References to the saying's mythological antecedents, the World Turtle and its counterpart the World Elephant, were made by a number of authors in the 17th and 18th centuries.[2][3] This mythology is frequently assumed to have originated in ancient India and other Hinduist beliefs.
Early variants of the saying do not always have explicit references
to infinite regression (i.e., the phrase "all the way down"). They often
reference stories featuring a World Elephant, World Turtle, or other similar creatures that are claimed to come from Hindu mythology. The first known reference to a Hindu source is found in a letter by Jesuit Emanual de Veiga (1549–1605), written at Chandagiri on 18 September 1599, in which the relevant passage reads:[5]
Alii dicebant terram novem
constare angulis, quibus cœlo innititur. Alius ab his dissentiens
volebat terram septem elephantis fulciri, elephantes uero ne
subsiderent, super testudine pedes fixos habere. Quærenti quis
testudinis corpus firmaret, ne dilaberetur, respondere nesciuit.
Others hold that the earth has nine
corners by which the heavens are supported. Another disagreeing from
these would have the earth supported by seven elephants, and the
elephants do not sink down because their feet are fixed on a tortoise.
When asked who would fix the body of the tortoise, so that it would not
collapse, he said that he did not know.
Veiga's account seems to have been received by Samuel Purchas, who has a close paraphrase in his Purchas His Pilgrims
(1613/1626),
"that the Earth had nine corners, whereby it was borne up by the Heaven.
Others dissented, and said, that the Earth was borne up by seven
Elephants; the Elephants' feet stood on Tortoises, and they were borne
by they know not what."[6] Purchas' account is again reflected by John Locke in his 1689 tract An Essay Concerning Human Understanding,
where Locke introduces the story as a trope referring to the problem of
induction in philosophical debate. Locke compares one who would say
that properties inhere in "Substance" to the Indian who said the world
was on an elephant which was on a tortoise, "But being again pressed to
know what gave support to the broad-back'd Tortoise, replied, something,
he knew not what".[2] The story is also referenced by Henry David Thoreau,
who writes in his journal entry of 4 May 1852: "Men are making speeches
... all over the country, but each expresses only the thought, or the
want of thought, of the multitude. No man stands on truth. They are
merely banded together as usual, one leaning on another and all together
on nothing; as the Hindoos made the world rest on an elephant, and
the elephant on a tortoise, and had nothing to put under the tortoise."[7]
Modern form
In the form of "rocks all the way down", the saying dates to at least 1838, when it was printed in an unsigned anecdote in the New-York Mirror about a schoolboy and an old woman living in the woods:
"The world, marm," said I, anxious
to display my acquired knowledge, "is not exactly round, but resembles
in shape a flattened orange; and it turns on its axis once in
twenty-four hours."
"Well, I don't know anything about its axes,"
replied she, "but I know it don't turn round, for if it did we'd be all
tumbled off; and as to its being round, any one can see it's a square
piece of ground, standing on a rock!"
"Standing on a rock! but upon what does that stand?"
"Why, on another, to be sure!"
"But what supports the last?"
"Lud! child, how stupid you are! There's rocks all the way down!"[1]
A version of the saying in its "turtle" form appeared in an 1854
transcript of remarks by preacher Joseph Frederick Berg addressed to Joseph Barker:
My opponent's reasoning reminds me
of the heathen, who, being asked on what the world stood, replied, "On a
tortoise." But on what does the tortoise stand? "On another tortoise."
With Mr. Barker, too, there are tortoises all the way down. (Vehement
and vociferous applause.)
Many 20th-century attributions claim that William James is the source of the phrase.[9]
James referred to the fable of the elephant and tortoise several times,
but told the infinite regress story with "rocks all the way down" in
his 1882 essay, "Rationality, Activity and Faith":
Like the old woman in the story who
described the world as resting on a rock, and then explained that rock
to be supported by another rock, and finally when pushed with questions
said it was "rocks all the way down," he who believes this to be a
radically moral universe must hold the moral order to rest either on an
absolute and ultimate should or on a series of shoulds "all the way down."[10]
The linguist John R. Ross also associates James with the phrase:
The following anecdote is told of
William James. [...] After a lecture on cosmology and the structure of
the solar system, James was accosted by a little old lady.
"Your
theory that the sun is the centre of the solar system, and the earth is a
ball which rotates around it has a very convincing ring to it, Mr.
James, but it's wrong. I've got a better theory," said the little old
lady.
"And what is that, madam?" inquired James politely.
"That we live on a crust of earth which is on the back of a giant turtle."
Not
wishing to demolish this absurd little theory by bringing to bear the
masses of scientific evidence he had at his command, James decided to
gently dissuade his opponent by making her see some of the inadequacies
of her position.
"If your theory is correct, madam," he asked, "what does this turtle stand on?"
"You're
a very clever man, Mr. James, and that's a very good question," replied
the little old lady, "but I have an answer to it. And it's this: The
first turtle stands on the back of a second, far larger, turtle, who
stands directly under him."
"But what does this second turtle stand on?" persisted James patiently.
To this, the little old lady crowed triumphantly,
"It's no use, Mr. James — it's turtles all the way down."
— J. R. Ross, Constraints on Variables in Syntax 1967[11]
In epistemology and other disciplines
The metaphor
is used as an example of the problem of infinite regress in
epistemology to show that there is a necessary foundation to knowledge,
as written by Johann Gottlieb Fichte in 1794:[12][page needed]
"If there is not to be any (system
of human knowledge dependent upon an absolute first principle) two cases
are only possible. Either there is no immediate certainty at all, and
then our knowledge forms many series or one infinite series, wherein
each theorem is derived from a higher one, and this again from a higher
one, et., etc. We build our houses on the earth, the earth rests on an
elephant, the elephant on a tortoise, the tortoise again--who knows on
what?-- and so on ad infinitum. True, if our knowledge is thus
constituted, we can not alter it; but neither have we, then, any firm
knowledge. We may have gone back to a certain link of our series, and
have found every thing firm up to this link; but who can guarantee us
that, if we go further back, we may not find it ungrounded, and shall
thus have to abandon it? Our certainty is only assumed, and we can
never be sure of it for a single following day."
How, therefore, shall we satisfy
ourselves concerning the cause of that Being whom you suppose the Author
of Nature, or, according to your system of Anthropomorphism, the ideal
world, into which you trace the material? Have we not the same reason to
trace that ideal world into another ideal world, or new intelligent
principle? But if we stop, and go no further; why go so far? why not
stop at the material world? How can we satisfy ourselves without going
on in infinitum? And, after all, what satisfaction is there in that
infinite progression? Let us remember the story of the Indian
philosopher and his elephant. It was never more applicable than to the
present subject. If the material world rests upon a similar ideal world,
this ideal world must rest upon some other; and so on, without end. It
were better, therefore, never to look beyond the present material world.
By supposing it to contain the principle of its order within itself, we
really assert it to be God; and the sooner we arrive at that Divine
Being, so much the better. When you go one step beyond the mundane
system, you only excite an inquisitive humour which it is impossible
ever to satisfy.
If everything must have a cause,
then God must have a cause. If there can be anything without a cause, it
may just as well be the world as God, so that there cannot be any
validity in that argument. It is exactly of the same nature as the
Hindu's view, that the world rested upon an elephant and the elephant
rested upon a tortoise; and when they said, 'How about the tortoise?'
the Indian said, 'Suppose we change the subject.'
A well-known scientist (some say it was Bertrand Russell)
once gave a public lecture on astronomy. He described how the earth
orbits around the sun and how the sun, in turn, orbits around the center
of a vast collection of stars called our galaxy. At the end of the
lecture, a little old lady at the back of the room got up and said:
"What you have told us is rubbish. The world is really a flat plate
supported on the back of a giant tortoise." The scientist gave a
superior smile before replying, "What is the tortoise standing on?"
"You're very clever, young man, very clever," said the old lady. "But
it's turtles all the way down!"
In our favored version, an Eastern
guru affirms that the earth is supported on the back of a tiger. When
asked what supports the tiger, he says it stands upon an elephant; and
when asked what supports the elephant he says it is a giant turtle. When
asked, finally, what supports the giant turtle, he is briefly taken
aback, but quickly replies "Ah, after that it is turtles all the way
down."
Solipsism (/ˈsɒlɪpsɪzəm/ (listen); from Latin solus, meaning 'alone', and ipse, meaning 'self') is the philosophical idea that only one's own mind is sure to exist. As an epistemological position, solipsism holds that knowledge of anything outside one's own mind is unsure; the external world and other minds cannot be known and might not exist outside the mind. As a metaphysical position, solipsism goes further to the conclusion that the world and other minds do not exist.
Varieties
There are varying degrees of solipsism that parallel the varying degrees of skepticism:
Metaphysical solipsism
Metaphysical solipsism is a variety of solipsism. Based on a philosophy of subjective idealism, metaphysical solipsists maintain that the self is the only existing reality and that all other realities, including the external world and other persons, are representations of that self, and have no independent existence.[citation needed] There are several versions of metaphysical solipsism, such as Caspar Hare's egocentric presentism (or perspectival realism), in which other people are conscious, but their experiences are simply not present.[citation needed]
Epistemological solipsism
Epistemological solipsism is the variety of idealism
according to which only the directly accessible mental contents of the
solipsistic philosopher can be known. The existence of an external world
is regarded as an unresolvable question rather than actually false.[2]
Further, one cannot also be certain as to what extent the external
world exists independently of one's mind. For instance, it may be that a
God-like being controls the sensations received by one's brain, making
it appear as if there is an external world when most of it (excluding
the God-like being and oneself) is false. However, the point remains
that epistemological solipsists consider this an "unresolvable"
question.[2]
Methodological solipsism
Methodological solipsism is an agnostic variant of solipsism.[citation needed] It exists in opposition to the strict epistemological requirements for "knowledge" (e.g. the requirement that knowledge must be certain). It still entertains the points that any induction is fallible.
Methodological solipsism sometimes goes even further to say that even
what we perceive as the brain is actually part of the external world,
for it is only through our senses that we can see or feel the mind. Only
the existence of thoughts is known for certain.
Importantly, methodological solipsists do not intend to conclude
that the stronger forms of solipsism are actually true. They simply
emphasize that justifications of an external world must be founded on
indisputable facts about their own consciousness. The methodological
solipsist believes that subjective impressions (empiricism) or innate knowledge (rationalism) are the sole possible or proper starting point for philosophical construction.[3] Often methodological solipsism is not held as a belief system, but rather used as a thought experiment to assist skepticism (e.g. Descartes' cartesian skepticism).[citation needed]
Main points
Denial of material existence, in itself, does not constitute solipsism.
Philosophers try to build knowledge on more than an inference or analogy. The failure of Descartes' epistemological enterprise brought to popularity the idea that all certain knowledge may go no further than "I think; therefore I exist"[4] without providing any real details about the nature of the "I" that has been proven to exist.[citation needed]
The theory of solipsism also merits close examination because it
relates to three widely held philosophical presuppositions, each itself
fundamental and wide-ranging in importance:[4]
My most certain knowledge is the content of my own mind—mythoughts, experiences, affects, etc.
There is no conceptual or logically necessary link between mental
and physical—between, say, the occurrence of certain conscious
experience or mental states and the 'possession' and behavioral
dispositions of a 'body' of a particular kind (see the brain in a vat).
To expand on this a little further, the conceptual problem here is that the previous assumes mind or consciousness
(which are attributes) can exist independent of some entity having this
capability, i.e., that an attribute of an existant can exist apart from
the existant itself. If one admits to the existence of an independent
entity (e.g., your brain) having that attribute, the door is open.
3. The experience of a given person is necessarily private to that person.
Some people hold that, while it cannot be proven that anything
independent of one's mind exists, the point that solipsism makes is
irrelevant. This is because, whether the world as we perceive it exists
independently or not, we cannot escape this perception (except via
death), hence it is best to act assuming that the world is independent
of our minds.[5]
For example, if one committed a crime, one is likely to be punished,
causing potential distress to oneself even if the world was not
independent of one's mind; therefore, it is in one's best interests and
is most convenient to assume the world exists independently of one's
mind.
There is also the issue of plausibility to consider. If one is
the only mind in existence, then one is maintaining that one's mind
alone created all of which one is apparently aware. This includes the
symphonies of Beethoven, the works of Shakespeare,
all of mathematics and science (which one can access via one's phantom
libraries), etc. Critics of solipsism find this somewhat implausible.
However, since as an example, people are able to construct entire worlds
inside their minds while having dreams when asleep, and people have had
dreams which included things such as music of Beethoven or the works of
Shakespeare or maths or science in them, solipsists do have
counter-arguments to justify their views being plausible.
Even if something exists, nothing can be known about it.
Even if something could be known about it, knowledge about it can't be communicated to others.
Much of the point of the Sophists was to show that "objective"
knowledge was a literal impossibility.
Descartes
The
foundations of solipsism are in turn the foundations of the view that
the individual's understanding of any and all psychological concepts (thinking, willing, perceiving, etc.) is accomplished by making an analogy with his or her own mental states; i.e., by abstraction from inner experience. And this view, or some variant of it, has been influential in philosophy since Descartes elevated the search for incontrovertible certainty to the status of the primary goal of epistemology, whilst also elevating epistemology to "first philosophy".[citation needed]
George Berkeley's arguments against materialism in favour of idealism provide the solipsist with a number of arguments not found in Descartes. While Descartes defends ontological dualism, thus accepting the existence of a material world (res extensa) as well as immaterial minds (res cogitans) and God, Berkeley denies the existence of matter but not minds, of which God is one.[7]
Relation to other ideas
Idealism and materialism
One
of the most fundamental debates in philosophy concerns the "true"
nature of the world—whether it is some ethereal plane of ideas or a
reality of atomic particles and energy. Materialism[8]
posits a real 'world out there,' as well as in and through us, that can
be sensed—seen, heard, tasted, touched and felt, sometimes with
prosthetic technologies corresponding to human sensing organs. (Materialists do not claim that human senses or even their prosthetics
can, even when collected, sense the totality of the 'universe'; simply
that what they collectively cannot sense cannot in any way be known to
us.)
Materialists do not find this a useful way of thinking about the ontology and ontogeny
of ideas, but we might say that from a materialist perspective pushed
to a logical extreme communicable to an idealist (an "Away Team"
perspective), ideas are ultimately reducible to a physically
communicated, organically, socially and environmentally embedded 'brain
state'. While reflexive existence is not considered by materialists to
be experienced on the atomic level, the individual's physical and mental
experiences are ultimately reducible to the unique tripartite
combination of environmentally determined, genetically determined, and
randomly determined interactions of firing neurons and atomic collisions.
As a correlative, the only thing that dreams and hallucinations
prove are that some neurons can reorganize and 'clean house' 'on break'
(often reforming according to emergent, prominent, or uncanny cultural
themes), misfire, and malfunction. But for materialists, ideas have no
primary reality as essences separate from our physical existence. From a
materialist "Home Team" perspective, ideas are also social (rather than
purely biological), and formed and transmitted and modified through the
interactions between social organisms and their social and physical
environments. This materialist perspective informs scientific
methodology, insofar as that methodology assumes that humans have no access to omniscience and that therefore human knowledge is an ongoing, collective enterprise that is best produced via scientific and logical conventions adjusted specifically for material human capacities and limitations.[citation needed]
Modern Idealists,
on the other hand, believe that the mind and its thoughts are the only
true things that exist. This is the reverse of what is sometimes called classical idealism or, somewhat confusingly, Platonic idealism due to the influence of Plato's Theory of Forms (εἶδος eidos or ἰδέα idea) which were not products of our thinking.[9] The material world is ephemeral,
but a perfect triangle or "beauty" is eternal. Religious thinking tends
to be some form of idealism, as God usually becomes the highest ideal
(such as Neoplatonism).[8][10][11] On this scale, solipsism can be classed as idealism.
Thoughts and concepts are all that exist, and furthermore, only the
solipsist's own thoughts and consciousness exist. The so-called
"reality" is nothing more than an idea that the solipsist has (perhaps
unconsciously) created.
Cartesian dualism
There is another option: the belief that both ideals and "reality" exist. Dualists commonly argue that the distinction between the mind (or 'ideas') and matter can be proven by employing Leibniz' principle of the identity of indiscernibles
which states that if two things share exactly the same qualities, then
they must be identical, as in indistinguishable from each other and
therefore one and the same thing. Dualists then attempt to identify
attributes of mind that are lacked by matter (such as privacy or
intentionality) or vice versa (such as having a certain temperature or
electrical charge).[12][13] One notable application of the identity of indiscernibles was by René Descartes in his Meditations on First Philosophy. Descartes concluded that he could not doubt the existence of himself (the famous cogito ergo sum argument), but that he could doubt the (separate) existence of his body. From this, he inferred that the person Descartes must not be identical to the Descartes body
since one possessed a characteristic that the other did not: namely, it
could be known to exist. Solipsism agrees with Descartes in this
aspect, and goes further: only things that can be known to exist for
sure should be considered to exist. The Descartes body could only exist as an idea in the mind of the person Descartes.[14][15]
Descartes and dualism aim to prove the actual existence of reality as
opposed to a phantom existence (as well as the existence of God in
Descartes' case), using the realm of ideas merely as a starting point,
but solipsism usually finds those further arguments unconvincing. The
solipsist instead proposes that his/her own unconscious is the author of
all seemingly "external" events from "reality".
Philosophy of Schopenhauer
The World as Will and Representation is the central work of Arthur Schopenhauer. Schopenhauer saw the human will as our one window to the world behind the representation, the Kantian thing-in-itself.
He believed, therefore, that we could gain knowledge about the
thing-in-itself, something Kant said was impossible, since the rest of
the relationship between representation and thing-in-itself could be
understood by analogy as the relationship between human will and human body.
Idealism
The idealist philosopher George Berkeley
argued that physical objects do not exist independently of the mind
that perceives them. An item truly exists only as long as it is
observed; otherwise, it is not only meaningless but simply nonexistent.
The observer and the observed are one. Berkeley does attempt to show
things can and do exist apart from the human mind and our perception,
but only because there is an all-encompassing Mind in which all "ideas"
are perceived – in other words, God, who observes all. Solipsism agrees
that nothing exists outside of perception, but would argue that Berkeley
falls prey to the egocentric predicament –
he can only make his own observations, and thus cannot be truly sure
that this God or other people exist to observe "reality". The solipsist
would say it is better to disregard the unreliable observations of
alleged other people and rely upon the immediate certainty of one's own
perceptions.[16]
Rationalism
Rationalism is the philosophical position that truth is best discovered by the use of reasoning and logic rather than by the use of the senses (see Plato's theory of Forms). Solipsism is also skeptical of sense-data.
Philosophical zombie
The theory of solipsism crosses over with the theory of the philosophical zombie in that all other seemingly conscious beings actually lack true consciousness, instead they only display traits of consciousness to the observer, who is the only conscious being there is.
One critical test is nevertheless to consider the induction from
experience that the externally observable world does not seem, at first
approach, to be directly manipulable purely by mental energies alone.
One can indirectly manipulate the world through the medium of the
physical body, but it seems impossible to do so through pure thought (e.g. via psychokinesis). It might be argued that if the external world were merely a construct of a single consciousness, i.e.
the self, it could then follow that the external world should be
somehow directly manipulable by that consciousness, and if it is not,
then solipsism is false. An argument against this states the notion that
such manipulation may be possible but barred from the conscious self
via the subconscious self, a 'locked' portion of the mind that is still
nevertheless the same mind. Lucid dreaming
might be considered an example of when these locked portions of the
subconscious become accessible. An argument against this might be
brought up in asking why the subconscious mind would be locked. Also,
the access to the autonomous ('locked') portions of the mind during the
lucid dreaming is obviously much different (for instance: is relatively
more transient) than the access to autonomous regions of the perceived nature.
The method of the typical scientist is materialist: they first
assume that the external world exists and can be known. But the
scientific method, in the sense of a predict-observe-modify loop, does
not require the assumption of an external world. A solipsist may perform
a psychological test on themselves, to discern the nature of the
reality in their mind - however David Deutsch
uses this fact to counter-argue: "outer parts" of solipsist, behave
independently so they are independent for "narrowly" defined (conscious) self.[18]
A solipsist's investigations may not be proper science, however, since
it would not include the co-operative and communitarian aspects of
scientific inquiry that normally serve to diminish bias.
Minimalism
Solipsism is a form of logicalminimalism.
Many people are intuitively unconvinced of the nonexistence of the
external world from the basic arguments of solipsism, but a solid proof
of its existence is not available at present. The central assertion of
solipsism rests on the nonexistence of such a proof, and strong
solipsism (as opposed to weak solipsism) asserts that no such proof can
be made. In this sense, solipsism is logically related to agnosticism in religion: the distinction between believing you do not know, and believing you could not have known.
However, minimality (or parsimony) is not the only logical virtue. A common misapprehension of Occam's Razor has it that the simpler theory is always the best. In fact, the principle is that the simpler of two theories of equal explanatory power
is to be preferred. In other words: additional "entities" can pay their
way with enhanced explanatory power. So the realist can claim that,
while his world view is more complex, it is more satisfying as an explanation.
Solipsism in infants
Some developmental psychologists believe that infants are solipsistic, and that eventually children infer that others have experiences much like theirs and reject solipsism.[19]
Hinduism
The earliest reference to Solipsism in Hindu philosophy is found in the Brihadaranyaka Upanishad, dated to early 1st millennium BCE.[20] The Upanishad
holds the mind to be the only god and all actions in the universe are
thought to be a result of the mind assuming infinite forms.[21] After the development of distinct schools of Indian philosophy, Advaita Vedanta and Samkhya schools are thought to have originated concepts similar to solipsism.[citation needed]
Advaita Vedanta
Advaita is one of the six most known Hindu philosophical systems and literally means "non-duality". Its first great consolidator was Adi Shankaracharya, who continued the work of some of the Upanishadic teachers, and that of his teacher's teacher Gaudapada.
By using various arguments, such as the analysis of the three states of
experience—wakefulness, dream, and deep sleep, he established the
singular reality of Brahman, in which Brahman, the universe and the Atman or the Self, were one and the same.
One who sees everything as nothing but the Self, and the Self in everything one sees, such a seer withdraws from nothing.
For the enlightened, all that exists is nothing but the Self, so how could any suffering or delusion continue for those who know this oneness?
The concept of the Self in the philosophy of Advaita could be interpreted as solipsism. However, the transhuman, theological implications of the Self in Advaita protect it from true solipsism as found in the west. Similarly, the Vedantic text Yogavasistha, escapes charge of solipsism because the real "I" is thought to be nothing but the absolute whole looked at through a particular unique point of interest.[22]
Advaita is also thought to strongly diverge from solipsism in
that, the former is a system of exploration of one's mind in order to
finally understand the nature of the self and attain complete knowledge.
The unity of existence is said to be directly experienced and
understood at the end as a part of complete knowledge. On the other
hand, solipsism posits the non-existence of the external void right at
the beginning, and says that no further inquiry is possible.[citation needed]
Samkhya and Yoga
Samkhya philosophy, which is sometimes seen as the basis of Yogic thought,[23]
adopts a view that matter exists independently of individual minds.
Representation of an object in an individual mind is held to be a mental
approximation of the object in the external world.[24] Therefore, Samkhya chooses representational realism
over epistemological solipsism. Having established this distinction
between the external world and the mind, Samkhya posits the existence of
two metaphysical realities Prakriti (matter) and Purusha (consciousness).
Buddhism
Some misinterpretations of Buddhism assert that external reality is an illusion, and sometimes this position is [mis]understood as metaphysical solipsism. Buddhist philosophy,
though, generally holds that the mind and external phenomena are both
equally transient, and that they arise from each other. The mind cannot
exist without external phenomena, nor can external phenomena exist
without the mind. This relation is known as "dependent arising" (pratityasamutpada).
The Buddha stated, "Within this fathom long body is the world,
the origin of the world, the cessation of the world and the path leading
to the cessation of the world".[25]
Whilst not rejecting the occurrence of external phenomena, the Buddha
focused on the illusion created within the mind of the perceiver by the
process of ascribing permanence to impermanent phenomena, satisfaction
to unsatisfying experiences, and a sense of reality to things that were
effectively insubstantial.
Mahayana
Buddhism also challenges as illusion the idea that one can experience
an 'objective' reality independent of individual perceiving minds.
From the standpoint of Prasangika (a branch of Madhyamaka
thought), external objects do exist, but are devoid of any type of
inherent identity: "Just as objects of mind do not exist [inherently],
mind also does not exist [inherently]".[26]
In other words, even though a chair may physically exist, individuals
can only experience it through the medium of their own mind, each with
their own literal point of view. Therefore, an independent, purely
'objective' reality could never be experienced.
The Yogacara
(sometimes translated as "Mind only") school of Buddhist philosophy
contends that all human experience is constructed by mind. Some later
representatives of one Yogacara subschool (Prajnakaragupta, Ratnakīrti)
propounded a form of idealism that has been interpreted as solipsism. A
view of this sort is contained in the 11th-century treatise of
Ratnakirti, "Refutation of the existence of other minds" (Santanantara dusana), which provides a philosophical refutation of external mind-streams from the Buddhist standpoint of ultimate truth (as distinct from the perspective of everyday reality).[27]
In addition to this, the Bardo Thodol,
Tibet's famous book of the dead, repeatedly states that all of reality
is a figment of one's perception, although this occurs within the
"Bardo" realm (post-mortem). For instance, within the sixth part of
section titled "The Root Verses of the Six Bardos", there appears the
following line: "May I recognize whatever appeareth as being mine own
thought-forms";[28] there are many lines in similar ideal.
A philosophical zombie or p-zombie in the philosophy of mind and perception is a hypothetical being that from the outside is indistinguishable from a normal human being but lacks conscious experience, qualia, or sentience.
For example, if a philosophical zombie was poked with a sharp object it
would not feel any pain sensation, yet could behave exactly as if it
does feel pain (it may say "ouch", recoil from the stimulus, and say
that it is feeling pain).
The notion of a philosophical zombie is used mainly in thought experiments intended to support arguments (often called "zombie arguments") against forms of physicalism such as materialism, behaviorism and functionalism.
Physicalism is the idea that all aspects of human nature can be
explained by physical means: specifically, all aspects of human nature
and perception can be explained from a neurobiological standpoint. Some
philosophers, such as David Chalmers, argue that since a zombie is defined as physiologically indistinguishable from human beings, even its logical possibility would be a sound refutation of physicalism, as it would establish that the existence of conscious experience is a further fact.[2] However, physicalists like Daniel Dennett counter that Chalmers's physiological zombies are logically incoherent and thus impossible.[3][4]
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 behaviorism,
according to which mental states exist solely as behavior: belief,
desire, thought, consciousness, and so on, are simply certain kinds of
behavior or tendencies towards behaviors. A p-zombie that is
behaviorally indistinguishable from a normal human being but lacks
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 even logically possible.
The unifying idea of the zombie is of a human that has no
conscious experience, but one might distinguish various types of zombie
used in different thought experiments as follows:
A behavioral zombie that is behaviorally indistinguishable from a human.
A neurological zombie that has a human brain and is generally physiologically indistinguishable from a human.[5]
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.[6]
According to physicalism, physical 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 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[7] and the kind of physicalism known as type-identity theory. 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 world but
entirely lacking conscious experience. The counterpart of every
conscious being in our world would be a p-zombie. Since such a world is
conceivable, Chalmers claims, it is metaphysically possible, which is
all the argument requires. Chalmers states: "Zombies are probably not
naturally possible: they probably cannot exist in our world, with its
laws of nature."[8] The outline structure of Chalmers' 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.
In fact we can conceive of a world physically indistinguishable from
our world but in which there is no consciousness (a zombie world). From
this (so Chalmers argues) it follows that such a world is
metaphysically possible.
The above is a strong formulation of the zombie argument. There are
other formulations of the zombies-type argument which follow the same
general form. The premises of the general zombies argument are implied
by the premises of all the specific zombie arguments. A general zombies
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 substitute 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 would imply that physical truths
don't metaphysically necessitate phenomenal truths. To formulate the
general form of the zombies argument, take the sentence 'P' to be true
if and only if the conjunct of all microphysical truths of our world
obtain, 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.
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).
Responses
Chalmers' argument is logically valid:
if its premises are true then the conclusion must be true. However,
other philosophers dispute that its premises are true. For example, is
such a world really possible? Chalmers states that "it certainly seems
that a coherent situation is described; I can discern no contradiction
in the description."[10]
This leads to the questions of the relevant notion of "possibility": is
the scenario described in premise 3 possible in the sense that is
suggested in premise 2? Most physicalist responses deny that the premise
of a zombie scenario is possible.
Many physicalist philosophers argued that this scenario
eliminates itself by its description; the basis of 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.
One can hold that zombies are a logical possibility but not a metaphysical possibility.
If logical possibility does not entail metaphysical possibility across
the domain of relevant truths, then the mere logical possibility of
zombies is not sufficient to establish their metaphysical possibility.
The zombie argument claims that one can tell by the power of reason that
such a "zombie scenario" is metaphysically possible. Chalmers states;
"From the conceivability of zombies, proponents of the argument infer
their metaphysical possibility"[8]
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.[11]
Another response is 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".[3][4] He coined the term "zimboes" – p-zombies that have second-order beliefs – to argue that the idea of a p-zombie is incoherent;[12] "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!".[4] Under (reductive) physicalism,
one is inclined to believe either that anyone including oneself might
be a zombie, or that no one can be a zombie – following from the
assertion that one's own conviction about being, or not being a zombie
is (just) a product of the physical world and is therefore no different
from anyone else's. P-zombies in an observed world would be
indistinguishable from the observer, even hypothetically (when the
observer makes no assumptions regarding the validity of their
convictions). Furthermore, when 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"[4] contradicting the original definition of a zombie.
Verificationism[1]
states that, 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. A related argument is
that of "zombie-utterance". If someone were to say they love the smell
of some food, a zombie producing the same reaction would be perceived as
a person having complex thoughts and ideas in their head indicated by
the ability to vocalize it. If zombies were without awareness of their
perceptions the idea of uttering words could not occur to them.
Therefore, if a zombie has the ability to speak, it is not a zombie.
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 was claiming to prove.[13] 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 lack phenomenal consciousness. If
zoombies existed, they would refute dualism because they would show that
consciousness is not nonphysical, i.e., is physical. Paralleling the
argument from Chalmers: It's conceivable that zoombies exist, so it's
possible they exist, so dualism is false. Given the symmetry between the
zombie and zoombie arguments, we can't arbitrate the
physicalism/dualism question a priori.[14]
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."[15]
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. However 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 they're not guaranteed to work when both used at the same
time. Hence Chalmers's argument needn't go through.[16]:448
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 doesn't mean we must accept it.
And indeed, the fact that Chalmers concludes we have epiphenomenal
mental states that don't cause our physical behavior seems one reason to
reject his principle.[16]:449–51
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.[17]
Related thought-experiments
Frank Jackson's Mary's room
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 Mary 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 were to experience 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 views 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 that which Davidson had 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.
