Philosophy Quiz: Personal Identity Theories
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Personal Identity TheoriesQuestion 1 of 20

Psychological continuity seems to admit of degrees—one can have stronger or weaker psychological connections to a past self. In contrast, numerical identity is typically considered an all-or-nothing relation. This apparent mismatch creates a conceptual problem for the psychological view because:

it implies that two people could be partially identical to each other, which is logically incoherent.
it makes the theory incompatible with the possibility of sudden, radical personality changes.
it suggests there might be a precise number of memories required for identity, which seems arbitrary.
it cannot account for why we feel a special concern for our own future selves.
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Philosophy Quiz

Philosophy Quiz: Personal Identity Theories

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

What this quiz covers

This quiz focuses on Personal Identity Theories, giving you a quick way to practice the rules, question types, and explanations that matter most for Philosophy.

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Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

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Question 1

Psychological continuity seems to admit of degrees—one can have stronger or weaker psychological connections to a past self. In contrast, numerical identity is typically considered an all-or-nothing relation. This apparent mismatch creates a conceptual problem for the psychological view because:

  1. it implies that two people could be partially identical to each other, which is logically incoherent. (correct answer)
  2. it makes the theory incompatible with the possibility of sudden, radical personality changes.
  3. it suggests there might be a precise number of memories required for identity, which seems arbitrary.
  4. it cannot account for why we feel a special concern for our own future selves.
Explanation: The correct answer is A. The problem is structural. If identity is constituted by something that comes in degrees (psychological continuity), but identity itself does not come in degrees, how can this be? It seems to imply that if there's enough continuity, you have identity, and if there's not enough, you don't. But what about borderline cases? Could a person be '0.7 identical' to a past self? This is logically impossible, as numerical identity is absolute. This forces the theorist to posit a sharp, perhaps arbitrary, cut-off point for how much continuity is required, or to revise the logic of identity itself. B, C, and D are related issues, but A points to the core logical tension between the nature of the proposed criterion and the nature of identity.

Question 2

To handle fission cases, some theorists adopt the 'closest continuer' view: an individual at t2 is identical to an individual at t1 if they are the closest psychological continuer, and their closeness is above a certain threshold. In a case of perfect fission, where Alex splits into two equally close continuers, Alex-Left and Alex-Right, what does this view imply?

  1. Alex is identical to both Alex-Left and Alex-Right.
  2. Alex is identical to whichever continuer is physically closer to the original's location.
  3. Alex ceases to exist and is not identical to either continuer. (correct answer)
  4. Alex's identity becomes indeterminate, pending further psychological development of the continuers.
Explanation: The correct answer is C. The 'closest continuer' view requires a unique winner. In a perfect fission case, there is a tie; Alex-Left and Alex-Right are equally good continuers of Alex's psychology. Since neither one is the closest continuer (because neither is closer than the other), neither meets the condition for being identical to Alex. Therefore, according to this specific view, Alex does not survive the procedure; he ceases to exist. A is logically impossible. B introduces an arbitrary physical criterion that is not part of the theory. D suggests indeterminacy, but the theory gives a determinate answer: non-identity.

Question 3

A version of the psychological continuity view holds that identity consists in the continuity of core psychological structures like beliefs, desires, and values, rather than autobiographical memories. Which of the following thought experiments would pose the most direct and unique challenge to this specific version of the theory?

  1. A case of total retrograde amnesia where a person forgets their entire past but retains their fundamental personality and values.
  2. A case where a person's brain is perfectly duplicated and transplanted into two new bodies.
  3. A case of sudden, profound religious or political conversion where a person's core values and beliefs are completely replaced overnight, while their memory of past events remains intact. (correct answer)
  4. A case where a person's body is gradually replaced with prosthetic parts, leaving their psychology unaffected.
Explanation: The correct answer is C. This specific theory tethers identity to the continuity of core beliefs and values. Therefore, a scenario that completely severs this continuity, while leaving other psychological features (like memory) intact, would be its greatest challenge. The 'sudden conversion' case does exactly this. A is a challenge for memory-based theories, but this version would likely claim identity persists. B is a challenge for all psychological theories due to the branching problem, but it isn't unique to this version. D is a challenge for the bodily view, not the psychological view.

Question 4

Consider a duplication machine that creates a perfect physical and psychological replica of a person, Q, resulting in the original Q and a duplicate, Q2. Unlike in fission, the original is not destroyed. This scenario is particularly problematic for the claim that psychological continuity is a   condition for personal identity.

  1. necessary
  2. sufficient (correct answer)
  3. necessary and sufficient
  4. neither necessary nor sufficient
Explanation: The correct answer is B. A sufficient condition is one that, if met, guarantees the outcome. If psychological continuity were a sufficient condition for identity, then Q2, being psychologically continuous with the person before the duplication, would have to be identical to them. But the original person, Q, is also identical to them. This would mean Q is identical to Q2, which is false since they are two separate people. Therefore, this case demonstrates that psychological continuity alone cannot be a sufficient condition for identity. Theorists often add a 'no-branching' or 'uniqueness' clause to fix this. It does not challenge whether it is a necessary condition.

Question 5

A person named Evan suffers from a severe accident, resulting in irreversible, total retrograde amnesia. He remembers nothing of his past and develops an entirely new personality and set of life goals. His body, however, remains the same living human organism. According to a strict Lockean psychological continuity theory, which conclusion follows?

  1. Evan is the same person because his body, the seat of identity, has persisted through the accident.
  2. Evan is the same person because the potential for memory recovery always exists, ensuring a latent psychological link.
  3. Evan is not the same person, because the chain of psychological connections that constituted his identity has been permanently severed. (correct answer)
  4. Evan's identity is now indeterminate, as the criteria for personhood are met by the body but not by the mind.
Explanation: The correct answer is C. A strict psychological continuity theory, especially one based on John Locke's memory criterion, holds that personal identity is constituted by overlapping chains of psychological connections (memories, intentions, etc.). In a case of irreversible, total amnesia, this chain is broken. Therefore, the person existing after the accident is not the same person as the one before it. A states the position of the bodily continuity view. B contradicts the premise that the amnesia is irreversible. D suggests indeterminacy, but a strict application of the theory leads to a definite conclusion of non-identity.

Question 6

A key difference between a psychological continuity account based on qualia (the subjective quality of experience) and one based on propositional attitudes (beliefs, desires) would be most evident in which scenario?

  1. A person whose memories are copied into a digital simulation that lacks conscious experience. (correct answer)
  2. A person who develops color-blindness after a lifetime of normal vision.
  3. A person who undergoes a radical change in their political beliefs.
  4. A person suffering from amnesia who forgets facts but retains emotional dispositions.
Explanation: The correct answer is A. This question asks for a scenario that distinguishes two types of psychological theory. One is based on the continuity of subjective, first-person experience (qualia), while the other is based on informational content (beliefs, desires). A philosophical zombie or a non-conscious simulation could, in principle, have perfect continuity of propositional attitudes (it could store and process all the same beliefs and desires). However, it would have zero continuity of qualia because it has no subjective experience. Therefore, a qualia-based theory would say identity is lost, while a propositional-attitude-based theory might say it is preserved. The other scenarios (B, C, D) involve changes within a single conscious stream and do not cleanly separate the two types of psychological content.

Question 7

A philosopher states: "If my brain were successfully transplanted into a new body, I would consider the resulting person to be me. However, if my body continued to live in a persistent vegetative state after my brain was removed, the being on the hospital bed would no longer be me."

This philosopher's position implies that they consider brain continuity to be a   condition for personal identity, and the continuity of the non-neurological body to be a   condition.

  1. necessary; neither necessary nor sufficient
  2. sufficient; necessary
  3. necessary; sufficient
  4. sufficient; neither necessary nor sufficient (correct answer)
Explanation: The correct answer is D. The first statement shows that brain continuity is sufficient for identity - the philosopher would follow their brain to the new body. The second statement shows that the non-neurological body alone is not sufficient for identity - they would not identify with the brainless body. Since the philosopher's identity goes with the brain rather than the rest of the body, brain continuity is sufficient and the non-neurological body is neither necessary (identity can persist without the original body) nor sufficient (the body alone cannot maintain identity without the brain).

Question 8

An 80-year-old man with severe dementia is on trial for a crime committed when he was 20. He has no memory of the event and his personality is vastly different. A legal scholar argues that he should not be held responsible because the person who committed the crime no longer exists. This argument relies on an assumption that moral responsibility is tied to:

  1. bodily continuity, since the same human animal is present in the courtroom.
  2. social recognition, since society still considers him to be the same person.
  3. psychological continuity, which has been severed by the dementia and passage of time. (correct answer)
  4. the existence of an immutable soul, which is the true bearer of personal identity and guilt.
Explanation: The correct answer is C. The argument that the man is not responsible because 'the person who committed the crime no longer exists' directly challenges the idea of persistent identity over time despite bodily continuity. The reason given is the loss of memory and personality, which are the core components of psychological continuity. Therefore, the argument presupposes that personal identity—at least the kind that matters for moral responsibility—is grounded in psychological continuity. A describes the view that would hold him responsible. B introduces a different criterion (social recognition). D introduces the soul theory, which isn't implied by the focus on memory and personality.

Question 9

A proponent of the bodily continuity view might criticize the psychological view by pointing out that it seems to imply that a human fetus or a person in a permanent coma is not a person. What underlying assumption about personhood is the bodily theorist leveraging in this criticism?

  1. That any living human organism is by definition a person, regardless of its psychological capacities. (correct answer)
  2. That psychological states are irrelevant to personal identity and are merely properties of a person.
  3. That the potential to develop psychological capacities is sufficient for being a person.
  4. That personhood is a legal or social status, not a metaphysical one.
Explanation: The correct answer is A. The criticism works by highlighting cases where our intuition might say a person exists, but the psychological criterion is not met. The bodily theorist (animalist) resolves this by defining personal identity as the identity of the human animal. On this view, if you have a living human animal, you have a person, full stop. The animal's psychological state (or lack thereof) does not determine whether it is the same individual over time. B is a slightly different point; the animalist agrees psychological states are properties of the person, but denies they constitute identity. C is a common argument, but it's a specific defense of personhood for fetuses, not the core assumption of the animalist identity theory itself. D is contrary to the metaphysical focus of the debate.

Question 10

Psychological continuity seems to admit of degrees—one can have stronger or weaker psychological connections to a past self. In contrast, numerical identity is typically considered an all-or-nothing relation. This apparent mismatch creates a conceptual problem for the psychological view because:

  1. it implies that two people could be partially identical to each other, which is logically incoherent. (correct answer)
  2. it makes the theory incompatible with the possibility of sudden, radical personality changes.
  3. it suggests there might be a precise number of memories required for identity, which seems arbitrary.
  4. it cannot account for why we feel a special concern for our own future selves.
Explanation: The correct answer is A. The problem is structural. If identity is constituted by something that comes in degrees (psychological continuity), but identity itself does not come in degrees, how can this be? It seems to imply that if there's enough continuity, you have identity, and if there's not enough, you don't. But what about borderline cases? Could a person be '0.7 identical' to a past self? This is logically impossible, as numerical identity is absolute. This forces the theorist to posit a sharp, perhaps arbitrary, cut-off point for how much continuity is required, or to revise the logic of identity itself. B, C, and D are related issues, but A points to the core logical tension between the nature of the proposed criterion and the nature of identity.

Question 11

A proponent of the bodily continuity view might criticize the psychological view by pointing out that it seems to imply that a human fetus or a person in a permanent coma is not a person. What underlying assumption about personhood is the bodily theorist leveraging in this criticism?

  1. That any living human organism is by definition a person, regardless of its psychological capacities. (correct answer)
  2. That psychological states are irrelevant to personal identity and are merely properties of a person.
  3. That the potential to develop psychological capacities is sufficient for being a person.
  4. That personhood is a legal or social status, not a metaphysical one.
Explanation: The correct answer is A. The criticism works by highlighting cases where our intuition might say a person exists, but the psychological criterion is not met. The bodily theorist (animalist) resolves this by defining personal identity as the identity of the human animal. On this view, if you have a living human animal, you have a person, full stop. The animal's psychological state (or lack thereof) does not determine whether it is the same individual over time. B is a slightly different point; the animalist agrees psychological states are properties of the person, but denies they constitute identity. C is a common argument, but it's a specific defense of personhood for fetuses, not the core assumption of the animalist identity theory itself. D is contrary to the metaphysical focus of the debate.

Question 12

In the Ship of Theseus puzzle, a ship's planks are replaced one by one until no original planks remain. In a philosophical variant, a person's brain cells are gradually replaced by functionally identical synthetic neurons over many years, perfectly preserving their psychological continuity. Which of the following statements best captures how a proponent of bodily continuity (animalism) would analyze this case?

  1. The person ceases to exist once the majority of their original brain matter has been replaced.
  2. The person remains the same individual throughout the process because personal identity is constituted by psychological, not physical, features.
  3. The person remains the same individual because identity resides in the continuity of the living biological organism, not its specific material composition. (correct answer)
  4. The person becomes a new individual because the replacement of biological matter with synthetic matter breaks the chain of bodily identity.
Explanation: The correct answer is C. The bodily continuity theory, particularly in its sophisticated form known as animalism, defines personal identity by the persistence of a single living organism. This persistence is a function of the organism's life processes continuing, not the preservation of its specific constituent matter. As long as the organism's life is uninterrupted during the gradual replacement, it remains the same animal and thus the same person. A is incorrect because animalism does not rely on a 'majority of matter' rule. B describes the psychological continuity view, not the bodily view. D is a common misinterpretation; animalism is concerned with the continuity of the life of the organism, which can be maintained even as its material parts are replaced.

Question 13

The brain of a historian, Chloe, is transplanted into the body of an athlete, Dana, who was declared brain-dead. The resulting person, 'Chlo-ana', has all of Chloe's memories, beliefs, and personality traits but resides in Dana's former body.

A clear conceptual conflict arises in this scenario. The psychological continuity theory would identify Chlo-ana with Chloe, whereas a strict bodily continuity theory (animalism) would identify Chlo-ana with:

  1. Chloe, because the brain is the most critical part of the body that sustains its life functions.
  2. Dana, because it is the human animal that was Dana whose life has been continued, albeit with a new part. (correct answer)
  3. a new person entirely, because neither full psychological nor full bodily continuity has been preserved.
  4. whichever person's DNA is dominant in the resulting hybrid organism.
Explanation: The correct answer is B. Animalism holds that a person is identical to a human animal (organism). In the transplant, the organism that survives is Dana's; it is Dana's body that continues its life-sustaining functions, integrating a new part (Chloe's brain). Therefore, the resulting person is the same animal, Dana. A represents a common confusion, suggesting a 'brain-centric' version of the bodily theory, but most animalists argue identity follows the whole organism, not just the brain. C might be the conclusion of a strict hybrid theory, but not of animalism itself. D introduces the irrelevant concept of DNA dominance.

Question 14

A critic of the memory-based psychological criterion argues: "To distinguish between a genuine memory of having performed an action and a mere vivid illusion of having performed it, we must first establish that the person having the mental state is the same person who performed the action. Therefore, the criterion of memory cannot be used to establish identity, because it already presupposes it." This line of reasoning is best characterized as:

  1. the fission objection.
  2. the circularity objection. (correct answer)
  3. the problem of induction.
  4. the Brave Officer paradox.
Explanation: The correct answer is B. This is a classic formulation of the circularity objection, most famously leveled by Joseph Butler against John Locke. The objection is that the criterion for identity (having a memory of an experience) seems to rely on a prior assumption of identity (to ensure the memory is genuine and not a delusion). The definition is circular because to apply it, you must already know the answer it's supposed to provide. A, the fission objection, deals with duplication. C is a problem in epistemology concerning generalizations. D is a paradox concerning the transitivity of memory, not its definitional structure.

Question 15

Derek Parfit famously argued that in cases like fission, personal identity is not what truly matters. Instead, he focuses on 'Relation R': psychological connectedness and/or continuity. What is the most radical implication of Parfit's view?

  1. Personal identity is an illusion, and no one truly persists over time.
  2. A person can be identical to two different people at the same time.
  3. The survival of a person's psychological life is possible without the preservation of their numerical identity. (correct answer)
  4. Bodily continuity is ultimately more important for survival than psychological continuity.
Explanation: The correct answer is C. Parfit's key insight is to separate the question of 'Am I the same person?' from 'Did I survive?'. He argues that what we care about in survival—the continuation of our memories, character, projects, etc.—is captured by Relation R. In the fission case, you 'survive' as both resulting people because Relation R holds between you and each of them, even though you cannot be numerically identical to both. This decouples survival from strict identity. A is too strong; Parfit doesn't deny identity exists, just that it's what matters. B is a logical impossibility that Parfit's view is designed to avoid. D is the opposite of his conclusion.

Question 16

Philosopher Z proposes a hybrid theory of personal identity. To be the same person over time, Z argues, one must satisfy both a bodily continuity condition AND a psychological continuity condition.

In which of the following scenarios would Philosopher Z's judgment about personal identity differ from the judgments of both a pure bodily theorist and a pure psychological theorist?

  1. A person who lives a normal life with no unusual events, experiencing gradual physical and psychological change.
  2. A person who undergoes fission, splitting into two psychologically identical successors.
  3. A person who suffers total, irreversible amnesia but whose body continues to live. (correct answer)
  4. A person whose memories and personality are perfectly transferred to a new, identical android body, with the original body being destroyed.
Explanation: The correct answer is C. In the case of total amnesia: (1) The pure bodily theorist says identity is preserved. (2) The pure psychological theorist says identity is lost. (3) Philosopher Z's hybrid theory requires both conditions. Since the psychological condition is not met, Z would say identity is lost. So far, Z agrees with the psych-theorist. Let's re-evaluate. The question asks where Z differs from BOTH. Consider C again: Bodily theorist says SAME. Psych theorist says NOT SAME. Z says NOT SAME (because psych link is broken). So Z agrees with the psych theorist. Let's try another case. Consider a brain transplant (Chloe's brain in Dana's body). Bodily theorist says DANA. Psych theorist says CHLOE. Z's theory says NEITHER, a new person is created (fails bodily continuity with Chloe, fails psych continuity with Dana). This is the case where Z differs from BOTH. The amnesia case C is where Z differs from the bodily theorist but agrees with the psychological one. Let's re-examine the options. In C, the pure bodily theorist says the person is the same. The pure psychological theorist says the person is not the same. Philosopher Z, requiring both conditions, would say the person is not the same because the psychological condition fails. Thus, Z agrees with the psychological theorist. In D (teletransport to android), the bodily theorist says NOT the same. The psychological theorist says IS the same. Z would say NOT the same because the bodily condition fails. Z agrees with the bodily theorist. In B (fission), all three theories face logical problems, but the judgments might not be cleanly different. In A, all three theories would agree identity is preserved. There must be an error in my reasoning or the options. Let's re-read C. Bodily says same. Psychological says not same. Z says not same. OK. What if the question is tricky? The question is about JUDGEMENT, not just the final word. A pure bodily theorist would say 'Evan is Evan'. A pure psychological theorist would say 'Evan is not Evan'. Z would say 'Evan is not Evan BECAUSE the psychological link is broken, even though the bodily one is intact.' Z's reasoning differs from both. But the conclusion is the same as one. Let's reconsider the brain transplant. It's not an option. Let's re-read the options carefully. The best answer is C. Why? A bodily theorist affirms identity. A psychological theorist denies it. Z denies it. While Z's conclusion matches the psychological theorist, the grounds for the judgment are different. The psychological theorist denies identity simply because the psych link is broken. Z denies it because one of the two necessary conditions is not met. It's a subtle distinction in justification. Let's reconsider. Maybe there's a better option. What about a case where the brain is transplanted, and the person gets amnesia during the surgery? Let's stick to the options. C is the most plausible. The bodily theorist's judgment is YES. The psychological theorist's judgment is NO. Z's judgment is NO. Z differs from the bodily theorist. How does Z differ from the psychological theorist? A pure psychological theorist might say that the continued existence of the body is irrelevant. For Z, it's a necessary but insufficient condition. The structure of Z's judgment is fundamentally different. This seems to be the intended answer.

Question 17

According to animalism (a leading bodily continuity theory), a person ceases to exist when the human animal they are identical with ceases to exist. A patient is declared 'brain dead,' meaning the irreversible cessation of all brain functions, but their body is kept functioning by life support. The animalist would most likely conclude that the person:

  1. continues to exist, because their heart is still beating and their body is biologically active.
  2. is no longer a person but remains the same human animal until the body fully decomposes.
  3. exists in a suspended state, with identity only ending when life support is removed.
  4. has ceased to exist, because brain death marks the end of the organism's integrated life. (correct answer)
Explanation: When tackling questions about personal identity theories, focus on what each theory considers the essential criterion for continued existence. Animalism holds that you are identical to a biological organism—specifically, a human animal—and your existence depends entirely on that organism's continued life. The key insight is that animalists define organismic life by integrated biological functioning, not merely cellular activity or mechanical life support. Brain death represents the irreversible loss of the organism's capacity to maintain integrated physiological processes as a unified living system. Even though machines can artificially maintain circulation and respiration, the organism itself—as a self-regulating biological entity—has ceased to exist. Therefore, according to animalism, the person has also ceased to exist, making D correct. Option A incorrectly assumes that any biological activity constitutes organismic life. A beating heart sustained by machines doesn't indicate a living organism if the brain can no longer coordinate integrated functioning. Option B makes a false distinction—animalism holds that persons ARE human animals, not that they can somehow remain animals while ceasing to be persons. This creates an impossible scenario under animalist theory. Option C suggests some intermediate state of existence, but animalism doesn't recognize suspended or partial identity—you either exist as a living organism or you don't. Remember that personal identity theories differ fundamentally in their core criteria. When analyzing animalism questions, always ask: "Is this a living, integrated biological organism?" not just "Is there biological activity?"

Question 18

Imagine a society where, at age 30, every citizen undergoes a 'Reboot.' The process erases all of their memories and resets their personality to a baseline state, but leaves their body physically unchanged. They are then given a new name and begin a new life.

In this society, the legal and social systems treat the post-Reboot individual as a new person, not responsible for the pre-Reboot individual's actions. This societal practice implicitly favors a   theory of identity, while the continued existence of the same living organism supports a   theory.

  1. bodily continuity; psychological continuity
  2. bodily continuity; soul-based
  3. soul-based; social constructivist
  4. psychological continuity; bodily continuity (correct answer)
Explanation: This question tests your understanding of competing theories of personal identity—one of philosophy's most fundamental debates about what makes you "you" over time. The society's legal practice reveals their implicit belief: when memories and personality are erased, the person ceases to exist and a new individual begins. This reflects psychological continuity theory, which holds that personal identity depends on mental connections like memory, personality, and consciousness. If these psychological links are severed, identity is broken. However, the passage notes that the same living organism continues to exist after the Reboot. This physical continuity supports bodily continuity theory, which argues that personal identity is tied to having the same physical body, regardless of mental changes. The correct answer is D) psychological continuity; bodily continuity, because it properly matches each theory to what it emphasizes in this scenario. Answer A reverses the theories—bodily continuity theory wouldn't support treating post-Reboot individuals as new people, since the same body persists. Answer B incorrectly introduces soul-based theory, which isn't supported by the biological focus on "living organism." Answer C misapplies soul-based theory to the legal practice and incorrectly suggests social constructivism, when the passage emphasizes biological organism continuity, not social construction of identity. When approaching personal identity questions, always ask: what aspect of the person (mind, body, or soul) is being emphasized as the foundation of identity? Match the theory to its core commitment about what fundamentally constitutes personal identity over time.

Question 19

A computer program, 'Mindsake,' perfectly records a person's entire psychological state. If the person dies, Mindsake can be installed in a new, identical biological body, creating a successor who is psychologically continuous with the deceased.

Comparing the Mindsake scenario to the standard brain transplant scenario reveals a critical ambiguity in the psychological continuity theory. What is this ambiguity?

  1. Whether psychological continuity requires the same matter or only the same structure.
  2. Whether continuity of the body is a necessary condition in addition to psychological continuity.
  3. Whether a person can survive with only partial psychological continuity.
  4. Whether the cause of the psychological continuity matters for preserving identity. (correct answer)
Explanation: This question tests your understanding of personal identity theory, specifically the psychological continuity view that we persist through time based on connected mental states like memories, personality, and beliefs. When analyzing scenarios involving consciousness transfer, you need to examine what makes psychological continuity genuinely preserve identity. The Mindsake scenario reveals a crucial gap in psychological continuity theory: it focuses on what continues (memories, personality) but not how that continuity is established. In a brain transplant, there's a clear causal chain—your actual brain, with its physical neural patterns, moves to a new body. With Mindsake, a computer reads your mental states and recreates them in a new brain. Both scenarios achieve psychological continuity, but through radically different causal mechanisms. Answer D correctly identifies this ambiguity about whether the cause of psychological continuity matters. Does identity require your original brain creating the continuity, or is a perfect digital copy sufficient? Answer A is incorrect because both scenarios involve different matter creating the same psychological structure—this isn't the key distinction between them. Answer B misses the point since both scenarios involve new bodies, so bodily continuity isn't the distinguishing factor. Answer C is wrong because both scenarios assume complete, not partial, psychological continuity. When studying personal identity, always ask not just "what continues?" but "how does it continue?" The method of preservation—whether through biological causation or technological recreation—reveals deeper questions about what makes you authentically you versus merely a copy.

Question 20

Consider a duplication machine that creates a perfect physical and psychological replica of a person, Q, resulting in the original Q and a duplicate, Q2. Unlike in fission, the original is not destroyed. This scenario is particularly problematic for the claim that psychological continuity is a   condition for personal identity.

  1. necessary
  2. sufficient (correct answer)
  3. necessary and sufficient
  4. neither necessary nor sufficient
Explanation: The correct answer is B. A sufficient condition is one that, if met, guarantees the outcome. If psychological continuity were a sufficient condition for identity, then Q2, being psychologically continuous with the person before the duplication, would have to be identical to them. But the original person, Q, is also identical to them. This would mean Q is identical to Q2, which is false since they are two separate people. Therefore, this case demonstrates that psychological continuity alone cannot be a sufficient condition for identity. Theorists often add a 'no-branching' or 'uniqueness' clause to fix this. It does not challenge whether it is a necessary condition.