Explosion of unserviceable ammunition and other military items The explosion of the Castle Bravo nuclear bomb.
An explosion is a rapid expansion in volume of a given amount of matter associated with an extreme outward release of energy, usually with the generation of high temperatures and release of high-pressure gases.
Explosions may also be generated by a slower expansion that would
normally not be forceful, but is not allowed to expand, so that when
whatever is containing the expansion is broken by the pressure that
builds as the matter inside tries to expand, the matter expands
forcefully. An example of this is a volcanic eruption created by the expansion of magma in a magma chamber as it rises to the surface. Supersonic explosions created by high explosives are known as detonations and travel through shock waves. Subsonic explosions are created by low explosives through a slower combustion process known as deflagration.
Causes
For
an explosion to occur, there must be a rapid, forceful expansion of
matter. There are numerous ways this can happen, both naturally and
artificially, such as volcanic eruptions, or two objects striking each other at very high speeds, as in an impact event. Explosive volcanic eruptions occur when magma rises from below, it has dissolved gas in it. The reduction of pressure
as the magma rises causes the gas to bubble out of solution, resulting
in a rapid increase in volume, however the size of the magma chamber
remains the same. This results in pressure buildup that eventually leads
to an explosive eruption. Explosions can also occur outside of Earth in
the universe in events such as supernovae, or, more commonly, stellar flares. Humans are also able to create explosions through the use of explosives, or through nuclear fission or fusion, as in a nuclear weapon. Explosions frequently occur during bushfires in eucalyptus forests where the volatile oils in the tree tops suddenly combust.
Among the largest known explosions in the universe are supernovae, which occur after the end of life of some types of stars. Solar flares
are an example of common, much less energetic, explosions on the Sun,
and presumably on most other stars as well. The energy source for solar
flare activity comes from the tangling of magnetic field lines resulting
from the rotation of the Sun's conductive plasma. Another type of large
astronomical explosion occurs when a meteoroid or an asteroid impacts
the surface of another object, or explodes in its atmosphere,
such as a planet. This occurs because the two objects are moving at
very high speed relative to each other (a minimum of 11.2 kilometres per
second (7.0 mi/s) for an Earth impacting body). For example, the Tunguska event of 1908 is believed to have resulted from a meteor air burst.
Black hole mergers, likely involving binary black hole systems, are capable of radiating many solar masses of energy into the universe in a fraction of a second, in the form of a gravitational wave.
This is capable of transmitting ordinary energy and destructive forces
to nearby objects, but in the vastness of space, nearby objects are
rare. The gravitational wave observed on 21 May 2019, known as GW190521,
produced a merger signal of about 100 ms duration, during which time is
it estimated to have radiated away nine solar masses in the form of
gravitational energy.
Chemical
The most common artificial explosives are chemical explosives, usually involving a rapid and violent oxidation
reaction that produces large amounts of hot gas. Gunpowder was the
first explosive to be invented and put to use. Other notable early
developments in chemical explosive technology were Frederick Augustus Abel's development of nitrocellulose in 1865 and Alfred Nobel's invention of dynamite
in 1866. Chemical explosions (both intentional and accidental) are
often initiated by an electric spark or flame in the presence of oxygen.
Accidental explosions may occur in fuel tanks, rocket engines, etc.
A high current electrical fault can create an "electrical explosion" by forming a high-energy electrical arc which rapidly vaporizes metal and insulation material. This arc flash hazard is a danger to people working on energized switchgear. Excessive magnetic pressure within an ultra-strong electromagnet can cause a magnetic explosion.
Mechanical and vapor
Strictly a physical process, as opposed to chemical or nuclear, e.g.,
the bursting of a sealed or partially sealed container under internal
pressure is often referred to as an explosion. Examples include an
overheated boiler or a simple tin can of beans tossed into a fire.
Boiling liquid expanding vapor explosions
are one type of mechanical explosion that can occur when a vessel
containing a pressurized liquid is ruptured, causing a rapid increase in
volume as the liquid evaporates. Note that the contents of the
container may cause a subsequent chemical explosion, the effects of
which can be dramatically more serious, such as a propane
tank in the midst of a fire. In such a case, to the effects of the
mechanical explosion when the tank fails are added the effects from the
explosion resulting from the released (initially liquid and then almost
instantaneously gaseous) propane in the presence of an ignition source.
For this reason, emergency workers often differentiate between the two
events.
In addition to stellar nuclear explosions, a nuclear weapon is a type of explosive weapon that derives its destructive force from nuclear fission
or from a combination of fission and fusion. As a result, even a
nuclear weapon with a small yield is significantly more powerful than
the largest conventional explosives available, with a single weapon
capable of completely destroying an entire city.
Properties
Force
A breaching charge exploding against a test door during trainingThe effects of a large explosion.
Explosive force is released in a direction perpendicular to the
surface of the explosive. If a grenade is in mid air during the
explosion, the direction of the blast will be 360°. In contrast, in a shaped charge
the explosive forces are focused to produce a greater local explosion;
shaped charges are often used by military to breach doors or walls.
Velocity
The
speed of the reaction is what distinguishes an explosive reaction from
an ordinary combustion reaction. Unless the reaction occurs very
rapidly, the thermally expanding gases will be moderately dissipated in
the medium, with no large differential in pressure and no explosion. As a
wood fire burns in a fireplace, for example, there certainly is the
evolution of heat and the formation of gases, but neither is liberated
rapidly enough to build up a sudden substantial pressure differential
and then cause an explosion. This can be likened to the difference
between the energy discharge of a battery, which is slow, and that of a flash capacitor like that in a camera flash, which releases its energy all at once.
Evolution of heat
The generation of heat in large quantities accompanies most explosive chemical reactions. The exceptions are called entropic explosives and include organic peroxides such as acetone peroxide. It is the rapid liberation of heat that causes the gaseous products of most explosive reactions to expand and generate high pressures.
This rapid generation of high pressures of the released gas constitutes
the explosion. The liberation of heat with insufficient rapidity will
not cause an explosion. For example, although a unit mass of coal yields
five times as much heat as a unit mass of nitroglycerin, the coal cannot be used as an explosive (except in the form of coal dust) because the rate at which it yields this heat is quite slow. In fact, a substance that burns less rapidly (i.e. slow combustion) may actually evolve more total heat than an explosive that detonates rapidly (i.e. fast combustion). In the former, slow combustion converts more of the internal energy (i.e.chemical potential) of the burning substance into heat released to the surroundings, while in the latter, fast combustion (i.e.detonation) instead converts more internal energy into work on the surroundings (i.e. less internal energy converted into heat); c.f.heat and work (thermodynamics) are equivalent forms of energy. See Heat of Combustion for a more thorough treatment of this topic.
When a chemical compound is formed from its constituents, heat
may either be absorbed or released. The quantity of heat absorbed or
given off during transformation is called the heat of formation.
Heats of formations for solids and gases found in explosive reactions
have been determined for a temperature of 25 °C and atmospheric
pressure, and are normally given in units of kilojoules per
gram-molecule. A positive value indicates that heat is absorbed during
the formation of the compound from its elements; such a reaction is
called an endothermic reaction. In explosive technology only materials
that are exothermic—that
have a net liberation of heat and have a negative heat of formation—are
of interest. Reaction heat is measured under conditions either of
constant pressure or constant volume. It is this heat of reaction that
may be properly expressed as the "heat of explosion."
Initiation of reaction
A
chemical explosive is a compound or mixture which, upon the application
of heat or shock, decomposes or rearranges with extreme rapidity,
yielding much gas and heat. Many substances not ordinarily classed as
explosives may do one, or even two, of these things.
A reaction must be capable of being initiated by the application of shock, heat, or a catalyst
(in the case of some explosive chemical reactions) to a small portion
of the mass of the explosive material. A material in which the first
three factors exist cannot be accepted as an explosive unless the
reaction can be made to occur when needed.
Fragmentation
Fragmentation
is the accumulation and projection of particles as the result of a high
explosives detonation. Fragments could originate from: parts of a
structure (such as glass, bits of structural material, or roofing material), revealed strata and/or various surface-level geologic features (such as loose rocks, soil, or sand),
the casing surrounding the explosive, and/or any other loose
miscellaneous items not vaporized by the shock wave from the explosion.
High velocity, low angle fragments can travel hundreds of metres with
enough energy to initiate other surrounding high explosive items, injure
or kill personnel, and/or damage vehicles or structures.
The Future History is a series of stories created by Robert A. Heinlein.
It describes a projected future of the human race from the middle of
the 20th century through the early 23rd century. The term Future History was coined by John W. Campbell Jr. in the February 1941 issue of Astounding Science Fiction. Campbell published an early draft of Heinlein's chart of the series in the May 1941 issue.
Heinlein wrote most of the Future History stories early in his career, between 1939 and 1941 and between 1945 and 1950. Most of the Future History stories written prior to 1967 are collected in The Past Through Tomorrow, which also contains the final version of the chart. That collection does not include Universe and Common Sense; they were published separately as Orphans of the Sky.
For the most part, The Past Through Tomorrow defines a core group of stories that are clearly within the Future History series. However, Heinlein scholars generally agree that some stories not included in the anthology belong to the Future History series, and that some that are included are only weakly linked to it.
James Gifford adds Time Enough for Love, which was published after The Past Through Tomorrow, and also "Let There Be Light", which was not included in The Past Through Tomorrow,
possibly because the collection editor disliked it or because Heinlein
himself considered it to be inferior. However, he considers Time Enough for Love to be a borderline case. He considers The Number of the Beast, The Cat Who Walks Through Walls, and To Sail Beyond the Sunset to be too weakly linked to the Future History to be included.
Bill Patterson includes To Sail Beyond the Sunset, on the theory that the discrepancies between it and the rest of the Future History are explained by assigning it to the same "bundle of related timelines" in the "World as Myth" multiverse. However, he lists a number of stories that he believes were never really intended to be part of Future History, even though they were included in The Past Through Tomorrow: "Life-Line"
(which was written before Heinlein published the Future History chart;
however, Lazarus Long does reference the protagonist of "Life-Line" and
his device in Time Enough for Love), "The Menace from Earth", "—We Also Walk Dogs", and the stories originally published in the Saturday Evening Post ("Space Jockey", "It's Great to Be Back!", "The Green Hills of Earth", and "The Black Pits of Luna"). He agrees with Gifford that "Let There Be Light" should be included. The story "—And He Built a Crooked House—" was included only in the pre-war chart and never since.
The Heinlein juveniles do not hew closely to the Future History outline. Gifford states that "Although the twelve juvenile novels are not completely inconsistent with the Future History,
neither do they form a thorough match with that series for adult
readers. It is not often recognized that they are a reasonably
consistent 'Future History' of their own... At least one major story
specified in the Future History chart, the revolution on Venus, ended up being told in the framework of the juveniles as Between Planets." The novel Variable Star, written by Spider Robinson from Heinlein's detailed outline, incorporates some elements of both the Future History
(such as references to Nehemiah Scudder) and the universe of the
Heinlein juveniles (for example, torch ships and faster-than-light
telepathic communication between twins). The adult short story "The Long Watch", included in Future History story collections, connects to Space Cadet through the character of (John) Ezra Dahlquist, the central character of the first, memorialized in the second.
Patterson cites "World as Myth" as a way of accounting for the
deviation of real history from Heinlein's imagined future as well as
inconsistencies between stories, writing, "Heinlein in the World as Myth
books redefined the Future History as a timeline (or bundle of related
timelines) ... which allows the 'Future History' to be a hard-edged term
and yet nevertheless contain inconsistencies (i.e., any inconsistency
belongs to a closely-related timeline)."
The chart published in the collection Revolt in 2100
includes several unwritten stories, which Heinlein describes in a
postscript. "Fire Down Below", about a revolution in Antarctica, would
have been set in the early 21st century. Three more unwritten stories
fill in the history from just before "Logic of Empire" in the early 21st century through the beginning of "If This Goes On—".
"The Sound of His Wings" covers Nehemiah Scudder's early life as a
television evangelist through his rise to power as the First Prophet.
"Eclipse" describes independence movements on Mars and Venus. "The Stone
Pillow" details the rise of the resistance movement from the early days
of the theocracy through the beginning of "If This Goes On—".
These stories were key points in the Future History, so Heinlein gave a rough description of Nehemiah Scudder which made his reign easy to visualize—a combination of John Calvin, Girolamo Savonarola, Joseph Franklin Rutherford, and Huey Long.
His rise to power began when one of his flock, the widow of a wealthy
man who would have disapproved of Scudder, died and left him enough
money to establish a television station. He then teamed up with an ex-Senator and hired a major advertising agency. He was soon famous even off-world—many bonded laborers on Venus saw him as a messianic figure. He had muscle as well—a re-creation of the Ku Klux Klan
in everything but name. "Blood at the polls and blood in the streets,
but Scudder won the election. The next election was never held." Though
this period was integral to the human diaspora that would follow several
hundred years later, Heinlein stated that he was never able to write
them because they featured Scudder prominently; he "dislike(d) him too
much".
Nehemiah Scudder already appears in Heinlein's earliest novel For Us, the Living: A Comedy of Customs
(written 1938–1939, though first published in 2003). Scudder's early
career as depicted in that book is virtually identical with the
above—but with the crucial difference that in the earlier version
Scudder is stopped at the last moment by the counter-mobilization of Libertarians, and despite mass voter intimidation carries only Tennessee and Alabama.
In fact, the Libertarian regime seen in full bloom in that book's 2086
came into being in direct reaction to Scudder's attempt to impose
puritanical mores on the entire American society.
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,
having no independent existence. 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.
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.
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 the mind, 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.
Methodological solipsism is an agnostic variant of solipsism. 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.
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. Often methodological solipsism is not held as a belief system, but rather used as a thought experiment to assist skepticism (e.g.René Descartes' Cartesian skepticism).
Main points
Mere denial of material existence, in itself, does not necessarily constitute solipsism.
Philosophers generally try to build knowledge on more than an
inference or analogy. Well-known frameworks such as Descartes'
epistemological enterprise brought to popularity the idea that all certain knowledge may go no further than "I think; therefore I exist." However, Descartes' view does not provide any details about the nature of the "I" that has been proven to exist.
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:
One's most certain knowledge is the content of one's own mind—mythoughts, experiences, affects, etc.
There is no conceptual or logically necessary link between mental
and physical—between, for example, the occurrence of certain conscious
experience or mental states and the "possession" and behavioral
dispositions of a "body" of a particular kind.
The experience of a given person is necessarily private to that person.
To expand on the second point, the conceptual problem is that the previous point assumes mind or consciousness
(which are attributes) can exist independent of some entity having this
attribute (a capability in this case), i.e., that an attribute of an
existent can exist apart from the existent itself. If one admits to the
existence of an independent entity (e.g., the brain) having that
attribute, the door is open to an independent reality. (See Brain in a vat)
Some philosophers 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, hence
it is best to act assuming that the world is independent of our minds.
(See Falsifiability and testability below)
History
Origins of solipsist thought are found in Greece and later Enlightenment thinkers such as Thomas Hobbes and Descartes.
Even if something exists, nothing can be known about it.
Even if something could be known about it, knowledge about it cannot be communicated to others.
Much of the point of the sophists was to show that objective knowledge was a literal impossibility.
René 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 their own mental states; i.e., by abstraction from inner experience.
And this view, or some variant of it, has been influential in
philosophy since René Descartes elevated the search for incontrovertible
certainty to the status of the primary goal of epistemology, whilst also elevating epistemology to "first philosophy".
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.
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
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 they collectively cannot sense what 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, 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.
For materialists, ideas have no primary reality as essences
separate from our physical existence. From a materialist perspective,
ideas are 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.
Modern idealists 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. 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).
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's 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). 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.
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 their 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.
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.
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 other seemingly conscious beings may actually lack true consciousness, instead they only display traits of consciousness to the observer, who may be the only conscious being there is.
Falsifiability and testability
Solipsism is not a falsifiable hypothesis as described by Karl Popper: there does not seem to be an imaginable disproof.
According to Popper: a hypothesis that cannot be falsified is not
scientific, and a solipsist can observe "the success of sciences" (see
also no miracles argument).
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 (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 that this
argument is circular and incoherent. It assumes at the beginning a
"construct of a single consciousness" meaning something false, and then
tries to manipulate the external world that it just assumed was false.
Of course this is an impossible task, but it does not disprove
solipsism. It is simply poor reasoning when considering pure idealized
logic and that is why David Deutsch states that when also other scientific methods are used (not only logic) solipsism is "indefensible", also when using the simplest explanations:
"If, according to the simplest explanation, an entity is complex and autonomous, then that entity is real."
The method of the typical scientist is naturalist: 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 Deutsch uses this fact to counter-argue:
"outer parts" of solipsist, behave independently so they are
independent for "narrowly" defined (conscious) self.
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 naturalist can claim that,
while their world view is more complex, it is more satisfying as an explanation.
Some developmental psychologists believe that infants are solipsistic, and that eventually children infer that others have experiences much like theirs and reject solipsism.
Hinduism
The earliest reference to solipsism is found in the ideas in Hindu philosophy in the Brihadaranyaka Upanishad, dated to early 1st millennium BC. 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. After the development of distinct schools of Indian philosophy, Advaita Vedanta and Samkhya schools are thought to have originated concepts similar to solipsism.
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 theological definition 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.
It is mentioned in Yoga Vasistha that “…..according to them (we
can safely assume that them are present Solipsists) this world is mental
in nature. There is no reality other than the ideas of one’s own mind.
This view is incorrect, because the world cannot be the content of an
individual’s mind. If it were so, an individual would have created and
destroyed the world according to his whims. This theory is called atma
khyati – the pervasion of the little self (intellect). Yoga Vasistha - Nirvana Prakarana - Uttarardha (Volume - 6) Page 107 by Swami Jyotirmayananda
Samkhya and Yoga
Samkhya philosophy, which is sometimes seen as the basis of Yogic thought,
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. 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 interpretations 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".
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 the illusion of 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]".
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 (Prajñakaragupta, 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).
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 the
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"; there are many lines in similar ideal.
Criticism
Solipsism
as radical subjective idealism has often been criticized by well-known
philosophers ("solipsism can only succeed in a madhouse" — A. Schopenhauer, "solipsism is madness" — M. Gardner.)
Bertrand Russell wrote that it was "psychologically impossible" to believe, "I once received a letter from an eminent logician, Mrs. Christine Ladd-Franklin,
saying that she was a solipsist, and was surprised that there were no
others. Coming from a logician and a solipsist, her surprise surprised
me".
He also argues that the logic of solipsism compels you to believe in
'solipsism of the moment' where only the presently existing moment can
be said to exist.
John Stuart Mill
wrote that one can know of others' minds because "First, they have
bodies like me, which I know in my own case, to be the antecedent
condition of feelings; and because, secondly, they exhibit the acts, and
outward signs, which in my own case I know by experience to be caused
by feelings".
The Dream of Human Life, by unknown artist, based on Michelangelo’s drawing The Dream, c. 1533
The dream argument is the postulation that the act of dreaming provides preliminary evidence that the senses we trust to distinguish reality from illusion
should not be fully trusted, and therefore, any state that is dependent
on our senses should at the very least be carefully examined and
rigorously tested to determine whether it is in fact reality.
Synopsis
While dreaming, one does not normally realize one is dreaming. On more rare occasions, the dream may be contained inside another dream with the very act of realizing that one is dreaming, itself, being only a dream that one is not aware of having. This has led philosophers to wonder whether it is possible for one ever to be certain,
at any given point in time, that one is not in fact dreaming, or
whether indeed it could be possible for one to remain in a perpetual
dream state and never experience the reality of wakefulness at all.
He who dreams of drinking wine may weep when morning
comes; he who dreams of weeping may in the morning go off to hunt. While
he is dreaming he does not know it is a dream, and in his dream he may
even try to interpret a dream. Only after he wakes does he know it was a
dream. And someday there will be a great awakening when we know that
this is all a great dream. Yet the stupid believe they are awake, busily
and brightly assuming they understand things, calling this man ruler,
that one herdsman—how dense! Confucius and you are both dreaming! And
when I say you are dreaming, I am dreaming, too. Words like these will
be labeled the Supreme Swindle. Yet, after ten thousand generations, a
great sage may appear who will know their meaning, and it will still be
as though he appeared with astonishing speed.
The Yogachara philosopher Vasubandhu (4th to 5th century C.E.) referenced the argument in his "Twenty verses on appearance only."
Dreaming provides a springboard for those who question whether our
own reality may be an illusion. The ability of the mind to be tricked
into believing a mentally generated world is the "real world" means at
least one variety of simulated reality is a common, even nightly event.
Those who argue that the world is not simulated must concede that
the mind—at least the sleeping mind—is not itself an entirely reliable
mechanism for attempting to differentiate reality from illusion.
Whatever I have accepted until now
as most true has come to me through my senses. But occasionally I have
found that they have deceived me, and it is unwise to trust completely
those who have deceived us even once.
— René Descartes
Critical discussion
In the past, philosophers John Locke and Thomas Hobbes
have separately attempted to refute Descartes's account of the dream
argument. Locke claimed that you cannot experience pain in dreams.
Various scientific studies conducted within the last few decades
provided evidence against Locke's claim by concluding that pain in
dreams can occur, but on very rare occasions.
Philosopher Ben Springett has said that Locke might respond to this by
stating that the agonizing pain of stepping into a fire is
non-comparable to stepping into a fire in a dream. Hobbes claimed that
dreams are susceptible to absurdity while the waking life is not.
Many contemporary philosophers have attempted to refute dream skepticism in detail (see, e.g., Stone (1984)). Ernest Sosa
(2007) devoted a chapter of a monograph to the topic, in which he
presented a new theory of dreaming and argued that his theory raises a
new argument for skepticism, which he attempted to refute. In A Virtue Epistemology: Apt Belief and Reflective Knowledge, he states: "in dreaming we do not really believe; we only make-believe."
Jonathan Ichikawa (2008) and Nathan Ballantyne & Ian Evans (2010)
have offered critiques of Sosa's proposed solution. Ichikawa argued that
as we cannot tell whether our beliefs in waking life are truly beliefs
and not imaginings, like in a dream, we are still not able to tell
whether we are awake or dreaming.
The dream hypothesis is also used to develop other philosophical concepts, such as Valberg's personal horizon: what this world would be internal to if this were all a dream.
Dream Skepticism
Norman Malcolm
in his monograph "Dreaming" (published in 1959) elaborated on
Wittgenstein's question as to whether it really mattered if people who
tell dreams "really had these images while they slept, or whether it
merely seems so to them on waking". He argues that the sentence "I am
asleep" is a senseless form of words; that dreams cannot exist
independently of the waking impression; and that skepticism based on
dreaming "comes from confusing the historical and dream telling
senses...[of]...the past tense" (page 120). In the chapter: "Do I Know I
Am Awake ?" he argues that we do not have to say: "I know that I am
awake" simply because it would be absurd to deny that one is awake.
Philosopher Daniel Dennett expanded on this idea with his cassette type hypothesis of dreaming.
He conjectured that dreams are not real conscious experiences, and are
instead pseudo-memories that emerge upon awakening from sleep. This
pseudo-memories do not correspond to any real dream experiences, and are
instead strictly fabrications of experiences that never occurred.
Philosopher Jennifer Windt has counter-argued against dream skepticism, drawing on the psychology of lucid dreaming, and has advanced a conceptual framework of dreaming as real imaginative experiences.
"Extraordinary claims require extraordinary evidence" (sometimes shortened to ECREE), also known as the Sagan standard, is an aphorism popularized by science communicator Carl Sagan. He used the phrase in his 1979 book Broca's Brain and the 1980 television program Cosmos. It has been described as fundamental to the scientific method and is regarded as encapsulating the basic principles of scientific skepticism.
The concept is similar to Occam's razor in that both heuristics
prefer simpler explanations of a phenomenon to more complicated ones.
In application, there is some ambiguity regarding when evidence is
deemed sufficiently "extraordinary". It is often invoked to challenge
data and scientific findings, or to criticize pseudoscientific claims.
Some critics have argued that the standard can suppress innovation and
affirm confirmation biases.
Philosopher David Hume characterized the principle in his 1748 essay "Of Miracles". Similar statements were made by figures such as Thomas Jefferson in 1808, Pierre-Simon Laplace in 1814, and Théodore Flournoy
in 1899. The formulation "Extraordinary claims require extraordinary
proof" was used a year prior to Sagan, by scientific skeptic Marcello Truzzi.
Critics state that it is impossible to objectively
define the term "extraordinary" and that measures of "extraordinary
evidence" are completely reliant on subjective evaluation. Ambiguity in
what constitutes "extraordinary" has led to misuse of the aphorism, and it is frequently invoked to discredit research dealing with scientific anomalies or any claim that falls outside the mainstream.
Application
An interesting debate has gone on within the [Federal Communications Commission] between those who think that all doctrines that smell of pseudoscience should be combated and those who believe that each issue should be judged on its own merits, but that the burden of proof
should fall squarely on those who make the proposals. I find myself
very much in the latter camp. I believe that the extraordinary should
certainly be pursued. But extraordinary claims require extraordinary
evidence.
The concept is related to Occam's razor as, according to such a heuristic,
simpler explanations are preferred to more complicated ones. Only in
situations where extraordinary evidence exists would an extraordinary
claim be the simplest explanation. It appears in hypothesis testing where the hypothesis that there is no evidence for the proposed phenomenon, what is known as the "null hypothesis", is preferred. The formal argument involves assigning a stronger Bayesian prior to the acceptance of the null hypothesis as opposed to its rejection.
Origin and precursors
Philosopher David Hume may have been the first to fully describe the principles of the Sagan standard.
Sagan popularized the aphorism in his 1979 book Broca's Brain, and in his 1980 television show Cosmos in reference to claims about extraterrestrials visiting Earth. Sagan had first stated the eponymous standard in a 1977 interview with The Washington Post. However, scientific skeptic Marcello Truzzi used the formulation "Extraordinary claims require extraordinary proof" in an article published by Parapsychology Review in 1975, as well as in a Zetetic Scholar article in 1978. Two 1978 articles quoted physicist Philip Abelson—then the editor of the journal Science—using the same phrasing as Truzzi.
In his 1748 essay "Of Miracles", philosopher David Hume
wrote that if "the fact ... partakes of the extraordinary and the
marvellous ... the evidence ... received a diminution, greater or less,
in proportion as the fact is more or less unusual".
Deming concluded that this was the first complete elucidation of the
standard. Unlike Sagan, Hume defined the nature of "extraordinary": he
wrote that it was a large magnitude of evidence.
Science communicator Carl Sagan
did not describe any concrete or quantitative parameters as to what
constitutes "extraordinary evidence", which raises the issue of whether
the standard can be applied objectively. Academic David Deming
notes that it would be "impossible to base all rational thought and
scientific methodology on an aphorism whose meaning is entirely
subjective". He instead argues that "extraordinary evidence" should be
regarded as a sufficient amount of evidence rather than evidence deemed
of extraordinary quality.
Tressoldi noted that the threshold of evidence is typically decided
through consensus. This problem is less apparent in clinical medicine
and psychology where statistical results can establish the strength of evidence.
Deming also noted that the standard can "suppress innovation and maintain orthodoxy". Others, like Etzel Cardeña, have noted that many scientific discoveries that spurred paradigm shifts
were initially deemed "extraordinary" and likely would not have been so
widely accepted if extraordinary evidence were required. Uniform rejection of extraordinary claims could affirm confirmation biases in subfields. Additionally, there are concerns that, when inconsistently applied, the standard exacerbates racial and gender biases. Psychologist Richard Shiffrin
has argued that the standard should not be used to bar research from
publication but to ascertain what is the best explanation for a
phenomenon. Conversely, mathematical psychologist Eric-Jan Wagenmakers stated that extraordinary claims are often false and their publication "pollutes the literature".
To qualify the publication of such claims, psychologist Suyog
Chandramouli has suggested the inclusion of peer reviewers' opinions on
their plausibility or an attached curation of post-publication peer
evaluations.
Cognitive scientist and AI researcher Ben Goertzel believes that the phrase is utilized as a "rhetorical meme" without critical thought. Philosopher Theodore Schick argued that "extraordinary claims do not require extraordinary evidence" if they provide the most adequate explanation. Moreover, theists and Christian apologists like William Lane Craig have argued that it is unfair to apply the standard to religious miracles
as other improbable claims are often accepted based on limited
testimonial evidence, such as an individual claiming that they won the
lottery.
