The Ship of Theseus is a paradox also known as Theseus' paradox. It raises the question of whether an object, which has had all its component parts replaced, remains fundamentally the same. Look up paradox in Wiktionary, the free dictionary. ... In philosophy, identity is whatever makes an entity definable and recognizable, in terms of possessing a set of qualities or characteristics that distinguish it from entities of a different type. ...

Variations of the paradox

Greek legend

According to Greek legend as reported by Plutarch, For other uses, see Legend (disambiguation). ... Mestrius Plutarchus (Greek: Πλούταρχος; 46 - 127), better known in English as Plutarch, was a Greek historian, biographer, essayist, and Middle Platonist. ...

Plutarch thus questions whether the ship would remain the same if it were entirely replaced, piece by piece. As a corollary, one can question what happens if the replaced parts were used to build a second ship. Which, if either, is the original Ship of Theseus? Theseus (Greek ) was a legendary king of Athens, son of Aethra, and fathered by Aegeus and Poseidon, with whom Aethra lay in one night (By some accounts, this was presented as a rape). ... This article is about the capital of Greece. ... For other uses, see Crete (disambiguation). ... Demetrius Phalereus ( - died approximately 280 BC) was an Athenian orator and one of the first Peripatetics. ... A philosopher is a person who thinks deeply regarding people, society, the world, and/or the universe. ...

Heraclitus's river

The Greek philosopher Heraclitus is notable for his unusual view of identity. Arius Didymus quoted^[1] him as saying: Heraclitus of Ephesus (Ancient Greek - Herákleitos ho Ephésios (Herakleitos the Ephesian)) (about 535 - 475 BC), known as The Obscure (Ancient Greek - ho Skoteinós), was a pre-Socratic Greek philosopher, a native of Ephesus on the coast of Asia Minor. ...

Plutarch also informs us of Heraclitus' claim about stepping twice into the same river, citing that it cannot be done because "it scatters and again comes together, and approaches and recedes"^[2]. Mestrius Plutarchus (Greek: Πλούταρχος; 46 - 127), better known in English as Plutarch, was a Greek historian, biographer, essayist, and Middle Platonist. ...

Locke's socks

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John Locke proposed a scenario regarding a favorite sock that develops a hole. He pondered whether the sock would still be the same after a patch was applied to the hole. If yes, then, would it still be the same sock after a second patch was applied? Indeed, would it still be the same sock many years later, even after all of the material of the original sock has been replaced with patches? Image File history File links Question_book-3. ... For other persons named John Locke, see John Locke (disambiguation). ... For other uses, see Sock (disambiguation). ...

Grandfather's old axe

"Grandfather's old axe" is a colloquial expression of unknown origin describing something of which little original remains: "it's had three new heads and four new handles but it's still the same old axe." The phrase has also been used in banter as in: "This is George Washington's original axe...", while holding up an apparently new axe. This example is used explicitly to explain significant points of the plot in The Fifth Elephant by Terry Pratchett. A similar example was also seen in Only Fools and Horses, where Trigger (a central character) won an award for using the same broom to sweep the streets for twenty years, even though he’d replaced the head 17 times and the handle 14 times. A colloquialism is an informal expression, that is, an expression not used in formal speech or writing. ... The Fifth Elephant is the 24th Discworld novel by Terry Pratchett. ... Terence David John Pratchett, OBE (born 28 April 1948) is a British fantasy and science fiction author, best known for his Discworld series. ... Only Fools and Horses is a British television sitcom, created and written by John Sullivan, and made and broadcast by the BBC. Seven series were originally broadcast in the UK between 1981 and 1991, with sporadic Christmas specials until 2003. ...

Other examples

One can think of many examples of objects which might fall prey to Theseus's paradox: buildings and automobiles for example can undergo complete replacement whilst still maintaining some aspect of their identity. Businesses, colleges and universities often change addresses and residences, thus completely "replacing" their old material structure for a new one, yet keeping the same purpose and often the same people that keep the organization functioning as it was. If two businesses merge, their identities merge (or one is consumed by the other). Similarly, the human body constantly creates new cells as old cells die. Average age of cells in an adult body may be less than 10 years. ^[3] Buildings are combinatorial structures on which groups act; the theory of buildings was introduced by Jacques Tits and expounded in Kenneth S. Browns excellent monograph Buildings. ... Car redirects here. ... The phrase mergers and acquisitions (abbreviated M&A) refers to the aspect of corporate strategy, corporate finance and management dealing with the buying, selling and combining of different companies that can aid, finance, or help a growing company in a given industry grow rapidly without having to create another business... Physical Features of the Human Body The human body is the entire physical structure of a human organism. ... Cells in culture, stained for keratin The cell is the structural and functional unit of all living organisms. ...

If we relate identity to actions and phenomena, identity becomes even harder to grasp. Depending upon one's chosen perspective of what identifies or continues a hurricane, if a hurricane Evan collapses at a particular location and then one forms again at or near the same location, a person may be totally consistent to either choose to call the latter mentioned hurricane the same as the former (as in "Evan" was reinvigorated), or choose to call the latter a new hurricane "Frank" or "Georgia".

One could also see the bands Napalm Death, Zao and The Little River Band as contemporary examples of Theseus's paradox. Both band's current line-ups contains none of the founding members, yet they continue to use the same name. Napalm Death is a grindcore/death metal band formed in the village of Meriden near Birmingham, England in 1982 by Nicholas Bullen and Miles Ratledge. ... For other uses of the term zao, see Zao (disambiguation). ... Little River Band is an Australian rock music band. ...

A somewhat, more layman's example is in most Herbie films. In these films, when any part of the protagonist (a "living" car named Herbie) is replaced, no one thinks anything of it, however; if one were to replace all of Herbie's parts at once, which part would contain his "soul", and if a certain car part DID contain his soul, would it be transferred if the part were attached to ANOTHER car?

Proposed resolutions

Aristotle's causes

According to the philosophical system of Aristotle and his followers, there are four causes or reasons that describe a thing; these causes can be analyzed to get to a solution to the paradox. The formal cause or form is the design of a thing, while the material cause is the matter that the thing is made of. The "what-it-is" of a thing, according to Aristotle, is its formal cause; so the Ship of Theseus is the same ship, because the formal cause, or design, does not change, even though the matter used to construct it may vary with time. In the same manner, for Heraclitus's paradox, a river has the same formal cause, although the material cause (the particular water in it) changes with time, and likewise for the person who steps in the river. For other uses, see Aristotle (disambiguation). ... Formal cause is a concept used by Aristotle, and originates from the idea of the form by Plato and Socrates. ... The Material Cause, that out of which the statue is made, is the marble or bronze. ...

Another of Aristotle's causes is the end or final cause, which is the intended purpose of a thing. The Ship of Theseus would have the same end, that is, transporting Theseus, even though its material cause would change with time. The efficient cause is how and by whom a thing is made, for example, how artisans fabricate and assemble something; in the case of the Ship of Theseus, the workers who built the ship in the first place could have used the same tools and techniques to replace the planks in the ship. Final cause is one of Aristotles four forms of causation (the others being material, formal, and efficient). ... The efficient cause is a philosophical concept proposed by Aristotle. ...

sion===Definitions of "the same"=== One common argument found in the philosophical literature is that in the case of Heraclitus's river we are tripped up by two different definitions of "the same". In one sense things can be qualitatively the same, by having the same properties. In another sense they might be numerically the same by being "one". As an example, consider two bowling balls that look identical. They would be qualitatively, but not numerically, the same. If one of the balls was then painted a different color, it would be numerically, but not qualitatively, the same as its previous self.

By this argument, Heraclitus's river is qualitatively, but not numerically, different by the time one attempts to make the second step into it. For Theseus's ship, the same is true.

The main problem with this proposed solution to problems of identity is that if we construe our definition of properties broadly enough, qualitative identity collapses into numerical identity. For example, if one of the qualities of a bowling ball is its spatial or temporal location, then no two bowling balls that exist in different places or points in time could ever be qualitatively identical. Likewise, in the case of a river, since it has different properties at every point in time—such as variance in the peaks and troughs of the waves in particular spatial locations, changes in the amount of water in the river caused by evaporation—it can never be qualitatively identical at different points in time. Since nothing can be qualitatively different without also being numerically different, the river must be numerically different at different points in time.

(A problem: "Since nothing can be qualitatively different without also being numerically different, the river must be numerically different at different points in time." - this contradicts the example in the first paragraph of the painted bowling ball)

(Actually, "nothing can be qualitatively different without also being numerically different" is a false claim. Not all qualities must be different for a thing to be, overall, qualitatively different. For instance, numerical value might be a quality factor that remains the same, while other qualities change.)

(I remind both of you of the existance of the discussion page)

Four dimensionalism

One solution to this paradox may come from the concept of four-dimensionalism. David Lewis and others have proposed that these problems can be solved by considering all things as 4-dimensional objects. An object is a spatially extended three-dimensional thing that also extends across the 4th dimension of time. This 4-dimensional object is made up of 3-dimensional time-slices. These are spatially extended things that exist only at individual points in time. An object is made up of a series of causally related time-slices. All time-slices are numerically identical to themselves. And the whole aggregate of time-slices, namely the 4-dimensional object, is also numerically identical with itself. But the individual time-slices can have qualities that differ from each other. In the philosophy of time, four dimensionalism is the view that reality is a four-dimensional continuum composed of time and space (spacetime). ...

The problem with the river is solved by saying that at each point in time, the river has different properties. Thus the various 3-dimensional time-slices of the river have different properties from each other. But the entire aggregate of river time-slices, namely the whole river as it exists across time, is identical with itself. So you can never step into the same river time-slice twice, but you can step into the same (4-dimensional) river twice.^[4]

A seeming difficulty with this is that in special relativity there is not a unique "correct" way to make these slices -- it is not meaningful to speak of a "point in time" extended in space. However, this does not prove to be a problem: any way of slicing will do (including no 'slicing' at all), provided that the boundary of the object changes in a fashion which can be agreed upon by observers in all reference frames. Special relativity still ensures that "you can never step into the same river time-slice twice", because even with the ability to shift around which way spacetime is sliced, you are still moving in a timelike fashion, which will not multiply intersect a time-slice, which is spacelike. For a less technical and generally accessible introduction to the topic, see Introduction to special relativity. ... In the context of special relativity, space-like separated points (or events) in spacetime have a spacetime interval less than 0 (see sign convention). ...

Metaphysics of quality

Robert M. Pirsig's metaphysics of quality, presented in Lila: An Inquiry into Morals, defines a hierarchy of patterns and uses it to offer another solution to the paradox: the ship is simultaneously a set of lower-order patterns (the parts) which change, and a single higher-order pattern (the ship as a whole) which remains constant. Robert Maynard Pirsig (born September 6, 1928, Minneapolis, Minnesota) is an American philosopher, mainly known as the author of the book Zen and the Art of Motorcycle Maintenance: An Inquiry into Values (1974), which has sold millions of copies around the world. ... The metaphysics of quality (MOQ) is a theory of reality introduced in Pirsigs philosophical novel Zen and the Art of Motorcycle Maintenance (1974) and expanded in Lila: An Inquiry into Morals (1991). ... Lila: An Inquiry into Morals (1991) is the second book by Robert M. Pirsig, who is best known for his cult favorite, Zen and the Art of Motorcycle Maintenance. ... The metaphysics of quality (MOQ) is a theory of reality introduced in Pirsigs philosophical novel Zen and the Art of Motorcycle Maintenance (1974) and expanded in Lila: An Inquiry into Morals (1991). ...

Madhyamika Buddhism

Within the Madhyamika school of Mahayana Buddhism, Candrakirti identifies the self as: Madhyamaka is a Buddhist philosophical tradition that asserts that all phenomena are empty of self-nature or essence (Sanskrit: Svabhāva), that they have no intrinsic, independent reality apart from the causes and conditions from which they arise. ... Relief image of the bodhisattva Kuan Yin from Mt. ... A statue of the Sakyamuni Buddha in Tawang Gompa, India. ... CandrakÄ«rti (born approx. ... Atman is a Sanskrit word, normally translated as soul or self (also ego). ...

an essence of things that does not depend on others; it is an intrinsic nature. The non-existence of that is selflessness.

-- Bodhisattvayogacaryācatuḥśatakaṭikā 256.1.7

Indeed the concept of Buddhist Emptiness is the strong assertion that all phenomena are empty of any essence - demonstrating that anti-essentialism lies at the very root of Buddhist praxis. Therefore, within this school it is the innate belief in essence that is considered to be the affliction which serves as the base of all suffering. However, the school also rejects the tenets of Idealism and Materialism; instead, the ideas of truth or existence, along with any assertions that depend upon them are limited to their function within the contexts and conventions that assert them, akin to Relativism or Pragmatism. For Madhyamakas, replacement paradoxes such as Ship of Theseus are answered by stating that the Ship of Thesesus remains so (within the conventions that assert it) until it ceases to function as the Ship of Theseus. In Buddhist philosophy, anatta (Pāli) or anātman (Sanskrit) refers to non-self or absence of separate self[1]. One scholar describes it as ...meaning non-selfhood, the absence of limiting self-identity in people and things. ... Śūnyatā, शून्यता (Sanskrit), Suññatā (Pāli), stong pa nyid (Tibetan), Kuu, 空 (Japanese) qoɣusun (Mongolian), generally translated into English as Emptiness or Voidness, is a concept of central importance in the teaching of the Buddha, as a direct realization of Sunyata is required to achieve liberation from the cycle of... For other uses, see Essence (disambiguation). ... This section may require cleanup to meet Wikipedias quality standards. ... In philosophy, materialism is that form of physicalism which holds that the only thing that can truly be said to exist is matter; that fundamentally, all things are composed of material and all phenomena are the result of material interactions; that matter is the only substance. ... For the physics theory with a similar name, see Theory of Relativity. ... Pragmatism is a philosophic school that originated in the late nineteenth century with Charles Sanders Peirce, who first stated the pragmatic maxim. ...

Cultural differences

This concept may differ among different cultures. As an anedocal evidence it seems that in the east this is not a paradox. Quoting Douglas Adams from the book Last Chance to See: Douglas Noël Adams (11 March 1952 – 11 May 2001) was an English author, comic radio dramatist, and musician. ... The front cover of the first US hardcover edition of Last Chance to See. ...

I remembered once, in Japan, having been to see the Gold Pavilion Temple in Kyoto and being mildly surprised at quite how well it had weathered the passage of time since it was first built in the fourteenth century. I was told it hadn't weathered well at all, and had in fact been burnt to the ground twice in this century. "So it isn't the original building?" I had asked my Japanese guide.

"But yes, of course it is," he insisted, rather surprised at my question.

"But it's burnt down?"

"Yes."

"Twice."

"Many times."

"And rebuilt."

"Of course. It is an important and historic building."

"With completely new materials."

"But of course. It was burnt down."

"So how can it be the same building?"

"It is always the same building."

I had to admit to myself that this was in fact a perfectly rational point of view, it merely started from an unexpected premise. The idea of the building, the intention of it, its design, are all immutable and are the essence of the building. The intention of the original builders is what survives. The wood of which the design is constructed decays and is replaced when necessary. To be overly concerned with the original materials, which are merely sentimental souvenirs of the past, is to fail to see the living building itself."

Kinkaku-ji from across the Kyōko-chi (Mirror Pond) Kinkaku-ji Golden Pavilion Temple) is the informal name of Rokuon-ji (鹿苑寺, Deer Garden Temple) in Kyoto, Japan. ... Location of Kyoto, on the main island of Japan Kyoto (Japanese: 京都市; Kyōto-shi) is a city in Japan that has a population of 1. ...

In popular culture

The Ship of Theseus paradox is addressed in Terry Pratchett's Discworld novel The Fifth Elephant. Here it is about an axe which periodically gets a new handle or a new blade. The characters in this book reason that, while it might not be the same axe physically, it will always remain the same axe emotionally. The Discworld series also pays homage to Heraclitus' statement by claiming that the (notoriously polluted and slow-moving to the point of being solid) River Ankh in the city of Ankh-Morpork is the only river that it is possible to cross twice. Terence David John Pratchett, OBE (born 28 April 1948) is a British fantasy and science fiction author, best known for his Discworld series. ... This article is about the novels. ... The Fifth Elephant is the 24th Discworld novel by Terry Pratchett. ...

There is a reference to the paradox in the BBC comedy Only Fools and Horses. The character Trigger, who is a road sweeper, wins an award for having used the same broom for many years and thus saving money. When he is asked about it, he reveals naively that both the handle and head of the broom have been replaced several times. Trigger is a dim-witted character who makes foolish remarks, and the joke here is that he believes the broom to be the same one as he has always had. For other uses, see BBC (disambiguation). ... Only Fools and Horses is a British television sitcom, created and written by John Sullivan, and made and broadcast by the BBC. Seven series were originally broadcast in the UK between 1981 and 1991, with sporadic Christmas specials until 2003. ... Colin Ball (DOB: 22nd April 1948), better known as Trigger (because he looks like a horse), is a character in the popular BBC sitcom Only Fools and Horses. ... A street sweeping machine in Cambridge, Massachusetts, USA. A Street sweeper is a person or machine that cleans streets, usually in an urban area. ...

In the 1986 book Foundation and Earth by Isaac Asimov, the ancient robot R. Daneel Olivaw says that over the thousands of years of his existence, every part of him has been replaced several times, including his brain, which he has carefully redesigned six times, replacing it each time with a newly constructed brain having the positronic pathways containing his current memories and skills, along with free space for him to learn more and continue operating for longer. Foundation and Earth Foundation and Earth (1986) is a science fiction novel by Isaac Asimov, the fifth novel of the Foundation Series and chronologically the last in the series. ... Isaac Asimov (January 2?, 1920?[1] – April 6, 1992), IPA: , originally Исаак Озимов but now transcribed into Russian as Айзек Азимов) was a Russian-born American Jewish author and professor of biochemistry, a highly successful and exceptionally prolific writer best known for his works of science fiction and for his popular science books. ... R. Daneel Olivaw is a fictional robot created by Isaac Asimov. ... The human brain In animals, the brain (enkephalos) (Greek for in the skull), is the control center of the central nervous system, responsible for behavior. ...

In So Long, and Thanks for All the Fish by Douglas Adams, Marvin the android claims he has undergone the same renovation, with the exception of the diodes down his left side (ironically, throughout the books he constantly complains of pain from just those diodes). So Long, and Thanks for All the Fish (1984, ISBN 0-345-39183-7) is the fourth book of the Hitchhikers Guide to the Galaxy series written by Douglas Adams. ... Douglas Noël Adams (11 March 1952 – 11 May 2001) was an English author, comic radio dramatist, and musician. ... Closeup of the image below, showing the square shaped semiconductor crystal various semiconductor diodes, below a bridge rectifier Structure of a vacuum tube diode In electronics, a diode is a two-terminal component, almost always one that has electrical properties which vary depending on the direction of flow of charge...

In the 1872 story Dr. Ox's Experiment by Jules Verne there is a reference to Jeannot's knife (the French equivalent of "Grandfather's old axe") apropos the van Tricasse's family. In this family, since 1340, each time one of the spouses died the other remarried with someone younger, who took the family name. is a short novel by the French writer and pioneer of Science-Fiction, Jules Verne, published in 1872. ... This article is about the French author. ...

The Heraclitus's river paradox is featured in Francis Ford Coppola's Apocalypse Now Redux in the newly added French plantation scene in a dialogue between Captain Willard and French colonist Roxanne: Francis Ford Coppola (born April 7, 1939) is a five-time Academy Award winning American film director, producer, and screenwriter. ... Apocalypse Now Redux is an extended, definitive version of Apocalypse Now. ...

Roxanne: "Do you know why you can never step into the same river twice?"

Willard: "Yeah, 'cause it's always moving."

It is also featured in Disney's Pocahontas, during the song "Just Around the Riverbend", in which Pocahontas sings "What I love most about rivers is you can't step in the same river twice; The water's always changing, always flowing" Disney may refer to: The Walt Disney Company and its divisions, including Walt Disney Pictures. ... Pocahontas is the thirty-third animated feature in the Disney animated features canon. ...

A variation of the paradox exists in the manga and anime, Ghost in the Shell. This article is about the comics published in East Asian countries. ... “Animé” redirects here. ... Motoko Kusanagi from the manga Ghost in the Shell. ...

Depending on the underlying technology, teleportation suffers from the same paradox. Teleportation is the movement of objects or elementary particles from one place to another, more or less instantaneously, without traveling through space. ...

See also

• Identity and change
• Mereological essentialism
• Philosophical zombie
• Sorites paradox
• Shunyata
• Standing wave

The relationship between identity and change in the philosophical field of metaphysics seems, at first glance, deceptively simple, and belies the complexity of the issues involved. ... Mereological essentialism is the view that objects have their parts essentially. ... In philosophy, a philosophical zombie or p-zombie is a hypothetical person that, despite a strong likeness to normal human beings, lacks conscious experience or (in other words) has no qualia at all. ... The Sorites paradox (σωρός (sōros) being Greek for heap and σωρίτης (sōritēs) the adjective) is a paradox that arises from vague predicates. ... Śūnyatā, शून्यता (Sanskrit), Suññatā (Pāli), stong pa nyid (Tibetan), Kuu, 空 (Japanese) qoɣusun (Mongolian), generally translated into English as Emptiness or Voidness, is a concept of central importance in the teaching of the Buddha, as a direct realization of Sunyata is required to achieve liberation from the cycle of... Vibration and standing waves in a string, The fundamental and the first 6 overtones A standing wave, also known as a stationary wave, is a wave that remains in a constant position. ...

References