Philosophy Quiz: Survival And Identity Over Time

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Survival And Identity Over TimeQuestion 1 of 20

A teleportation device scans a person, destroys them, and creates a molecule-for-molecule perfect replica at a destination. A proponent of the Bodily Criterion of identity argues against this being a method of survival. Their argument hinges on the distinction between two types of identity. Which of the following best articulates their objection?

The replica is only qualitatively identical to the original person but not numerically identical, as there is no spatiotemporal continuity of the body.

The replica is numerically identical but not qualitatively identical, because experiencing destruction and recreation is a significant change in properties.

The process fails to preserve the person's narrative identity, as the story of their life has been unnaturally interrupted and restarted.

The replica lacks the original's soul, which is the true basis of identity, even if the physical body is perfectly duplicated.

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Philosophy Quiz: Survival And Identity Over Time

Practice Survival And Identity Over Time in Philosophy with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.

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Question 1

The replica is only qualitatively identical to the original person but not numerically identical, as there is no spatiotemporal continuity of the body. (correct answer)
The replica is numerically identical but not qualitatively identical, because experiencing destruction and recreation is a significant change in properties.
The process fails to preserve the person's narrative identity, as the story of their life has been unnaturally interrupted and restarted.
The replica lacks the original's soul, which is the true basis of identity, even if the physical body is perfectly duplicated.

Explanation: The correct answer is A. This distinction is crucial in metaphysics. Qualitative identity means 'being exactly alike,' sharing all the same properties. Numerical identity means 'being one and the same object.' The Bodily Criterion requires the persistence of the same body through a continuous path in space and time. The teleportation process breaks this spatiotemporal continuity. Therefore, while the replica is a perfect copy (qualitatively identical), it is a new object, not the same one (numerically identical). (B) incorrectly reverses the terms; the replica is, by definition, qualitatively identical. (C) is an objection from the perspective of narrative identity, not the Bodily Criterion. (D) is an objection from the perspective of a soul-based view, not the Bodily Criterion.

Question 2

A philosopher, Anya, agrees to have her neurons gradually replaced with functionally identical synthetic neurons over ten years. By the end, her brain is entirely synthetic but functions identically to her original brain, preserving all her memories and personality traits. She calls the resulting person "Anya-2".

According to a Parfitian view of what matters in survival, which statement most accurately analyzes Anya's situation?

Anya has survived as Anya-2 because what matters is the continuity of her physical brain, regardless of its material composition.
Anya has not survived, because strict numerical identity requires the persistence of the original organic substance of her brain.
Anya has survived completely, because what matters, psychological continuity (Relation R), has been fully preserved through the functional equivalence of the new parts. (correct answer)
Anya has survived only to a certain degree, because psychological connectedness weakens with any change, even functional replacement.

Explanation: The correct answer is C. Derek Parfit's view, particularly his concept of 'Relation R,' prioritizes psychological continuity and connectedness. In this scenario, the gradual replacement of neurons with functionally identical synthetic ones ensures a seamless, overlapping chain of psychological states. Therefore, psychological continuity is perfectly preserved, meaning what matters for survival has been fully maintained. (A) is incorrect because this describes a version of the Bodily Criterion (or perhaps a Brain Criterion) focused on functional organization, not the Parfitian psychological view. (B) is incorrect because this represents the strict, substance-based view of identity that Parfit argues against. Parfit's point is that survival can occur even if strict numerical identity (in this material sense) does not. (D) is incorrect because while Parfit distinguishes between continuity and connectedness, the gradual nature of the replacement is designed to preserve the strong, overlapping chains that constitute full continuity. There is no reason to believe connectedness has weakened in a way that would diminish survival.

Question 3

In the Ship of Theseus paradox, Ship A is the ship whose planks are replaced one by one, while Ship B is the ship reassembled from the old, discarded planks.

Some philosophers argue that Ship A is the true Ship of Theseus. Which of the following principles provides the strongest support for this conclusion?

The principle of material constitution, which states that an object is identical to the matter that composes it at any given time.
The principle of functional persistence, which holds that identity is maintained as long as the object continues to perform its characteristic function.
The principle of majority, which asserts that an object remains the same as long as more than fifty percent of its original parts are intact.
The principle of spatiotemporal continuity and causal history, which emphasizes the gradual, unbroken path of an object's existence through space and time. (correct answer)

Explanation: The Ship of Theseus paradox tests your understanding of personal identity theory - specifically, what makes an object remain "the same" object over time despite changes. When approaching identity puzzles like this, focus on which philosophical principle best explains our intuitions about continuous existence. The principle of spatiotemporal continuity and causal history (D) provides the strongest support for Ship A being the true Ship of Theseus because it emphasizes the unbroken, gradual transformation process. Ship A maintains an uninterrupted presence in space and time - it never ceases to exist, and each plank replacement follows causally from the previous state. This continuous path of existence, with each change building on the last, preserves identity through gradual transformation. Option A fails because the principle of material constitution would actually support Ship B, since Ship B contains the original matter that once constituted the Ship of Theseus. Option B, functional persistence, doesn't distinguish between the ships - both Ship A and Ship B can perform the same sailing functions, so this principle can't determine which is the "true" ship. Option C, the principle of majority, creates an arbitrary threshold and would suggest the ship loses its identity once 51% of parts are replaced, regardless of continuity. When tackling identity paradoxes, remember that spatiotemporal continuity often trumps material composition in philosophical arguments. The key insight is that gradual change preserving causal connections tends to maintain identity better than reassembly or replacement that breaks the continuous existence chain.

Question 4

Consider a modified teletransporter. It scans you on Earth, creates a perfect replica on Mars, but fails to destroy the original you on Earth. You watch the replica appear on a screen, and then you walk out of the scanner.

Most people, including proponents of psychological continuity, would agree that the person on Earth is the original and the one on Mars is a copy. What does this intuition reveal about what matters in survival?

It shows that psychological continuity is not a sufficient condition for identity, as a 'no branching' or 'non-rival' condition is also intuitively required. (correct answer)
It proves that only the physical body is the basis for identity, as the original body's persistence is the deciding factor.
It suggests that the person on Mars is a 'zombie' who lacks consciousness, even if they are psychologically identical.
It confirms Parfit's view that identity is not what matters, as you have survived on both Earth and Mars.

Explanation: The correct answer is A. This scenario, a variation of fission, highlights a major problem for the simple view that psychological continuity is sufficient for identity. Both the person on Earth and the person on Mars are psychologically continuous with the original person. Yet, our strong intuition is that you are the one on Earth. This suggests that psychological continuity isn't the whole story. An additional condition, such as spatiotemporal continuity or a 'no-rivals' clause (i.e., identity only holds if there isn't more than one candidate), seems necessary to capture our intuitions about identity. (B) is too strong a conclusion. While the scenario supports the importance of the body, it doesn't definitively prove it's the only thing that matters. The key logical point is the challenge to the sufficiency of the psychological criterion. (C) introduces the unrelated problem of consciousness and p-zombies. (D) states Parfit's conclusion, but the question asks what the common intuition in this case reveals. That intuition is that you have not traveled, which is a problem for simple psychological theories and motivates the need for a more complex account like Parfit's or a 'closest continuer' view.

Question 5

A patient, David, suffers a car accident resulting in total retrograde amnesia, erasing all memories of his life before the accident. He subsequently builds a new life with new memories and a different personality.

According to a strict Lockean memory criterion of personal identity, which conclusion follows?

David is the same person he was before the accident, because he has the same living body and brain.
David is a different person from his pre-accident self, as there is no chain of memory connecting the two. (correct answer)
David is the same person, because what matters is the potential for memory retrieval, even if the memories are currently inaccessible.
David's identity is indeterminate until it can be known whether his psychological traits are caused by the same underlying brain states.

Explanation: The correct answer is B. John Locke's criterion for personal identity is the continuity of consciousness, which he primarily links to memory. If person B can remember the experiences of person A, then B and A are the same person. In this case, there is a complete break in the chain of memory. The post-accident David has no conscious link to the pre-accident David. Therefore, according to a strict interpretation of Locke's criterion, he is a new person. (A) applies the Bodily Criterion, not the Lockean one. (C) suggests a modification to the Lockean view to deal with cases of forgetting, but the question specifies a strict Lockean criterion based on actual memory links. (D) shifts the criterion from memory to brain states, which is a different version of a psychological or physical theory.

Question 6

Scientist A's brain is scanned, and its exact neurochemical state is transferred to Scientist B's brain, overwriting B's original state completely. Scientist A's original body is kept alive but is now braindead. The person with B's body now has all of A's memories, personality, and beliefs, and claims to be Scientist A.

Which statement represents the most significant point of disagreement between a proponent of the Bodily Criterion and a proponent of the Psychological Criterion?

Whether the person with B's body is qualitatively identical to Scientist A.
Whether Scientist A's original body is still considered a living human being.
Whether the person with B's body is numerically identical to the original Scientist A. (correct answer)
Whether the process of transferring a brain state is scientifically feasible.

Explanation: The correct answer is C. The core of the debate on personal identity is about the conditions for numerical identity over time. A proponent of the Psychological Criterion would argue that the continuity of memories, personality, etc., is sufficient for identity, so the person with B's body is Scientist A. A proponent of the Bodily Criterion would argue that spatiotemporal continuity of the body (or at least the brain) is necessary, so the person with B's body is not Scientist A, but rather Scientist B with A's memories. Their fundamental disagreement is over which individual is numerically the same as the original Scientist A. (A) is incorrect because both would likely agree that the resulting person is psychologically very similar, or qualitatively identical in that respect. (B) is a side issue; the main philosophical question is about the identity of the person, not the biological status of the braindead body. (D) is irrelevant, as thought experiments in philosophy stipulate the scenario is possible in order to probe our concepts.

Question 7

A person, Kai, is offered a choice. He can undergo a procedure that will result in his death but create two successors. Successor Kai-A will be an exact duplicate and live a life similar to Kai's. Successor Kai-B will also be an exact duplicate initially but will be given an enhancement that guarantees a happier, more successful life.

From a purely Parfitian perspective on rational self-interest, what should Kai do?

Refuse the procedure, as the loss of one-to-one identity means he does not survive, and the well-being of successors is irrelevant.
Be indifferent between his original life and the procedure, as the survival relation holds for both successors equally at the moment of fission.
Choose to create only Kai-B and not Kai-A, as this maximizes the overall quality of future experience connected to him.
Choose the procedure, as it leads to better outcomes for his psychological successors, which is what a rational agent should want for their future selves. (correct answer)

Explanation: When you encounter questions about personal identity and survival, you need to understand Derek Parfit's revolutionary view that psychological continuity matters more than strict numerical identity. For Parfit, what makes survival rational isn't maintaining one continuous body or soul, but preserving the psychological connections that constitute your ongoing mental life. From a Parfitian perspective, Kai should choose the procedure because rational self-interest extends to all his psychological successors. Since both Kai-A and Kai-B will have his memories, personality, and mental patterns, they represent genuine continuations of his psychological life—they are his future selves in the only sense that matters. A rational agent should want the best possible outcomes for these future psychological states, making option D correct. Option A reflects a traditional view of identity that Parfit explicitly rejects—the idea that strict one-to-one survival is necessary for rational self-concern. Option B misunderstands Parfit's position by suggesting mere indifference; Parfit argues we should actively care about our psychological successors' well-being. Option C makes the mistake of thinking Kai must choose between successors, when the scenario allows for both, and Parfit would say both successors have equal claim to being Kai's continuation. Remember that Parfitian questions test whether you can abandon intuitive notions of personal identity in favor of psychological continuity. When you see branching identity scenarios, ask yourself: "What would maximize well-being for all psychological successors?" rather than "How can strict identity be preserved?"

Question 8

A person commits a serious crime but then, before being caught, suffers a brain injury that causes a complete personality change and total amnesia regarding their entire past life. They now live as a peaceful, law-abiding citizen with no psychological connection to the person who committed the crime.

A judge must decide whether to punish this person. Which statement best reflects the dilemma created by the conflict between different theories of identity?

The Bodily Criterion would support punishment because the same human organism committed the crime, while a strict Lockean view would argue against it, as the person who committed the crime no longer exists. (correct answer)
Both the Bodily and Psychological criteria would support punishment, as the underlying brain that caused the crime is still present.
The Narrative Criterion would support punishment, as the person's life story now includes both the crime and the brain injury, and they must take responsibility for the entire narrative.
No theory of identity would support punishment, because justice requires conscious intent, which is absent in the post-injury person.

Explanation: The correct answer is A. This scenario perfectly illustrates the practical conflict between identity criteria. According to the Bodily Criterion, personal identity consists in the persistence of the same living body. Since the body that committed the crime is present in the courtroom, that person should be punished. According to a strict Lockean (memory-based) Psychological Criterion, the person is constituted by psychological continuity. Since that continuity has been completely severed, the person who committed the crime no longer exists, and it would be unjust to punish this new, different person. (B) is incorrect because a strict psychological view would not support punishment. (C) is a possible interpretation of the narrative view, but it's not the most direct conflict presented, and one could also argue from a narrative perspective that the story was irrecoverably broken. (D) confuses a metaphysical question about identity with a legal question about the conditions for culpability (mens rea). While related, the core philosophical dilemma here is about who this person is.

Question 9

Zara's brain is recorded, and two exact physical and psychological duplicates (Zara-A and Zara-B) are created in separate locations while Zara's original body is destroyed. Zara-A is placed in an environment identical to Zara's old life, while Zara-B is placed in a radically different environment and immediately begins forming new, distinct memories.

According to Derek Parfit's theory, what is the most plausible conclusion about what has happened to Zara?

Zara has survived as Zara-A but not as Zara-B, because only Zara-A continues the original life narrative and psychological patterns.
Zara has not survived, because identity is a one-to-one relation, and since she cannot be identical to two different people, she is identical to neither.
Zara has survived, and what matters for her survival exists in both Zara-A and Zara-B, even though their psychological lives will diverge over time. (correct answer)
Zara has survived as the combined entity of Zara-A and Zara-B, meaning she now exists in a distributed, non-localized form.

Explanation: The correct answer is C. This is a classic fission case, which Parfit uses to distinguish survival from strict identity. For Parfit, what matters is Relation R (psychological continuity and/or connectedness). At the moment of fission, Zara stands in Relation R to both Zara-A and Zara-B. Therefore, she has survived through both successors. The fact that their lives will diverge does not change this fact. (A) is incorrect because it arbitrarily privileges one successor over the other. For Parfit, the survival relation holds equally with both at the point of creation. (B) correctly describes why fission is a problem for strict identity, but it misses Parfit's main point, which is that survival can happen without strict identity. He would say this shows identity is not what matters. (D) is an interesting metaphysical speculation but is not Parfit's central claim. Parfit's analysis focuses on the relations between the individuals, not on positing a new kind of distributed entity.

Question 10

Imagine a society that has fully embraced Derek Parfit's conclusion that strict, all-or-nothing personal identity is not what matters, but rather psychological continuity and connectedness (Relation R). In this society, a technology exists that allows people to 'branch' into multiple successors.

Which of the following social practices would be most rationally justified according to this Parfitian framework?

Instituting a strict one-successor-per-person rule to avoid the metaphysical problems of fission and ensure the continuation of a single self.
Treating the pre-fission person's promises and contracts as null and void for all successors, since the original person no longer uniquely exists.
Assigning responsibility for the pre-fission person's crimes to only the successor who is most psychologically connected to the state of mind of the criminal.
Viewing branching as a desirable form of survival, where the pre-fission person has a rational self-interest in the well-being and projects of all their future successors. (correct answer)

Explanation: The correct answer is D. If what matters for survival is Relation R, and branching (fission) allows Relation R to hold between the original person and multiple successors, then branching is a way of multiplying what matters. A person's rational self-interest, which is grounded in Relation R, would naturally extend to all successors. Therefore, wanting them to flourish is the most rational stance. (A) is contrary to the Parfitian view, as it tries to preserve the old framework of one-to-one identity that Parfit argues is not what truly matters. (B) is incorrect because the successors, being psychologically continuous with the original, have good reason to see themselves as bound by prior commitments. (C) is a plausible but problematic solution to responsibility. Since both successors are fully psychologically continuous at the start, they would both seem to inherit the responsibility. Parfit's view makes assigning responsibility complex, but this option oversimplifies it and may not be the most rational approach.

Question 11

Over 50 years, a person named Sam undergoes a radical transformation of beliefs, values, and personality traits. The person he is at 70 ("Sam-70") shares no significant psychological traits or core beliefs with the person he was at 20 ("Sam-20"). A philosopher argues, "Sam-70 is not the same person as Sam-20, any more than a rebuilt ship is the same as the original."

This argument relies on an analogy to the Ship of Theseus paradox. What must be true for this analogy to be effective in challenging Sam's identity over time?

Psychological traits must be viewed as discrete, replaceable parts, and personal identity must depend on the persistence of a majority of these original parts. (correct answer)
There must be a second person who has acquired all of Sam-20's original psychological traits for the paradox to be complete.
Sam must have no memory of being Sam-20, as memory is the only factor that could bridge the psychological gap.
The change in Sam's psychology must be caused by an external force rather than natural development for the analogy to hold.

Explanation: The correct answer is A. The Ship of Theseus paradox works by conceptualizing an object as a collection of parts and then questioning identity when those parts are replaced. For the analogy to apply to Sam, his psychological profile must similarly be treated as a collection of discrete components (beliefs, values, traits). The argument's force comes from the claim that since all (or most) of these 'parts' have been replaced, the original entity no longer exists. (B) refers to the second part of the paradox (reassembling the old planks), which creates a conflict over which ship is the original. While this would strengthen the analogy, it's not necessary for the initial challenge to the identity of the continuously-modified person/ship. (C) is incorrect because the argument can still be made even if Sam-70 remembers being Sam-20. The claim would be that the person he remembers having been is no longer him, due to the radical change in constituent psychological parts. (D) is incorrect because the cause of the change is irrelevant to the logical structure of the analogy, which concerns only the replacement of parts.

Question 12

Proponents of a narrative view of personal identity argue that a person is constituted by the story they tell about their life, integrating past, present, and future. Which of the following scenarios presents the most significant challenge specifically for this narrative conception of the self?

An individual whose brain is transplanted into a new body, but who retains all memories and continues their life story without interruption.
Two individuals who live such similar lives and have such overlapping experiences that their life stories are nearly indistinguishable from an external perspective.
An individual who is a pathological liar, constantly fabricating and retelling a life story that bears no resemblance to the actual events of their past. (correct answer)
An individual who experiences gradual memory loss in old age, leading to a fragmented and incomplete life story.

Explanation: The correct answer is C. The narrative view grounds identity in the self-told story. This raises a crucial question: must the story be true? A pathological liar who constructs a compelling but entirely false narrative about themselves poses a direct challenge. If the narrative constitutes the self, is this person's selfhood constituted by a fiction? This forces the narrative theorist to address the relationship between narrative, truth, and identity in a way other scenarios do not. (A) is not a problem for the narrative view; in fact, the continuity of the story despite the bodily change is something the theory handles well. (B) is a general problem of distinguishing individuals, but not a specific challenge to the internal constitution of the self via narrative. (D) is a problem for any theory of identity that relies on memory or psychology, including Locke's and Parfit's, not one unique to the narrative view.

Question 13

Derek Parfit distinguishes between psychological connectedness (direct psychological links, like memory and intention) and psychological continuity (overlapping chains of connectedness). How does this distinction allow Parfit's theory to overcome Reid's Brave Officer paradox?

It claims that while the general is not psychologically connected to the boy, he is psychologically continuous with him, and continuity is what constitutes identity. (correct answer)
It suggests that connectedness is what matters for survival, not continuity, so the general has not survived from the boy stage.
It demonstrates that both connectedness and continuity are flawed concepts and that a physical criterion is ultimately required to solve the paradox.
It redefines memory so that the general does have a direct connection to the boy through a 'chain of consciousness,' making the paradox irrelevant.

Explanation: The correct answer is A. Reid's paradox shows that direct memory links are not transitive. Parfit's solution is to define a new relation, psychological continuity, which is transitive. Continuity exists when there is a series of overlapping direct connections. In the paradox, the General is connected to the Officer, and the Officer is connected to the Boy. This creates an overlapping chain of connectedness, which means the General is psychologically continuous with the Boy, even if he is not directly connected to him via memory. By making continuity the criterion for identity, transitivity is preserved. (B) is incorrect; Parfit argues continuity is the basis for identity/survival, while connectedness is a matter of degree that grounds our special concern. (C) is incorrect because the distinction is introduced specifically to save the psychological criterion from this objection. (D) is incorrect because the distinction doesn't redefine memory; it builds the new concept of continuity on top of existing connections like memory.

Question 14

A philosopher argues: "If a future person will be psychologically continuous with me, I have a reason to care about that person's well-being. This reason is just as strong whether that continuity is one-to-one or branching. Therefore, what justifies my egoistic concern for my own future is not strict identity, but the psychological relation itself."

Which philosophical position does this argument most directly support?

The Bodily Criterion, where concern for one's future is concern for a particular physical organism's future.
The Soul Criterion, where concern for one's future is rooted in the welfare of an enduring, immaterial substance.
Parfit's Reductionist View, where personal identity is not a deep further fact and what matters is Relation R (psychological continuity/connectedness). (correct answer)
A Narrative View, where concern for one's future is based on the desire for a coherent and fulfilling life story.

Explanation: The correct answer is C. This argument is a concise summary of Derek Parfit's central thesis in Reasons and Persons. He argues that personal identity is not some deep, further fact beyond physical and psychological continuity. He uses fission (branching) cases to argue that what grounds our rational concern for our future is Relation R (psychological continuity and connectedness), and that this relation is what matters, not a strict, one-to-one identity relation. (A) and (B) are incorrect as the argument explicitly bases future concern on psychological relations, not a body or soul. (D) is related, as narrative is a psychological phenomenon, but the specific focus on the one-to-one vs. branching issue is the hallmark of Parfit's analysis.

Question 15

According to Parfit, psychological connectedness (direct links like memory and intention) is a matter of degree and typically lessens over time. A 70-year-old has fewer direct psychological connections to their 20-year-old self than to their 60-year-old self. What is the most significant philosophical implication Parfit draws from this observation?

That personal identity is an illusion and no one truly persists from one moment to the next.
That a person's rational egoistic concern for their own future should also be a matter of degree, potentially weakening for the distant future. (correct answer)
That we have a moral obligation to frequently review our past memories in order to strengthen our psychological connectedness and preserve our identity.
That true personal identity only exists over short time spans where connectedness is high, and we become a new person every few years.

Explanation: The correct answer is B. Parfit argues that what matters in survival and what grounds our special, egoistic concern for our future is psychological connectedness and continuity (Relation R). Since connectedness, a key component of R, comes in degrees and weakens over time, the rational justification for our special concern should also weaken. It may be fully rational to care less about the well-being of your distant-future self than your near-future self, in much the same way you care less about a stranger than a close friend. (A) is an overstatement. Parfit is a reductionist (identity just consists in these other relations), not an eliminativist (identity doesn't exist at all). (C) is a possible practical application, but it's not the central philosophical implication Parfit is known for drawing. (D) is incorrect because Parfit maintains that identity, which relies on continuity (the all-or-nothing ancestral relation of connectedness), does persist over a whole life. The more radical claim is about what matters, which comes in degrees.

Question 16

According to Derek Parfit's theory, what is the most plausible conclusion about what has happened to Zara?

Zara has survived as Zara-A but not as Zara-B, because only Zara-A continues the original life narrative and psychological patterns.
Zara has not survived, because identity is a one-to-one relation, and since she cannot be identical to two different people, she is identical to neither.
Zara has survived, and what matters for her survival exists in both Zara-A and Zara-B, even though their psychological lives will diverge over time. (correct answer)
Zara has survived as the combined entity of Zara-A and Zara-B, meaning she now exists in a distributed, non-localized form.

Question 17

Which of the following social practices would be most rationally justified according to this Parfitian framework?

Instituting a strict one-successor-per-person rule to avoid the metaphysical problems of fission and ensure the continuation of a single self.
Treating the pre-fission person's promises and contracts as null and void for all successors, since the original person no longer uniquely exists.
Assigning responsibility for the pre-fission person's crimes to only the successor who is most psychologically connected to the state of mind of the criminal.
Viewing branching as a desirable form of survival, where the pre-fission person has a rational self-interest in the well-being and projects of all their future successors. (correct answer)

Question 18

An individual whose brain is transplanted into a new body, but who retains all memories and continues their life story without interruption.
Two individuals who live such similar lives and have such overlapping experiences that their life stories are nearly indistinguishable from an external perspective.
An individual who is a pathological liar, constantly fabricating and retelling a life story that bears no resemblance to the actual events of their past. (correct answer)
An individual who experiences gradual memory loss in old age, leading to a fragmented and incomplete life story.

Question 19

It shows that psychological continuity is not a sufficient condition for identity, as a 'no branching' or 'non-rival' condition is also intuitively required. (correct answer)
It proves that only the physical body is the basis for identity, as the original body's persistence is the deciding factor.
It suggests that the person on Mars is a 'zombie' who lacks consciousness, even if they are psychologically identical.
It confirms Parfit's view that identity is not what matters, as you have survived on both Earth and Mars.

Question 20

In the Ship of Theseus paradox, Ship A is the ship whose planks are replaced one by one, while Ship B is the ship reassembled from the old, discarded planks.

Some philosophers argue that Ship A is the true Ship of Theseus. Which of the following principles provides the strongest support for this conclusion?

The principle of material constitution, which states that an object is identical to the matter that composes it at any given time.
The principle of functional persistence, which holds that identity is maintained as long as the object continues to perform its characteristic function.
The principle of majority, which asserts that an object remains the same as long as more than fifty percent of its original parts are intact.
The principle of spatiotemporal continuity and causal history, which emphasizes the gradual, unbroken path of an object's existence through space and time. (correct answer)