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distinguish numerical identity from similarity and evidence, reconstruct competing persistence criteria, and explain the branching problem without assuming a preferred criterion
Paper packet. Every task here also exists on screen, where it is checked automatically; answers written on paper are not assessed by Nydus. When you are back at a device, enter your answers there.
You will distinguish numerical identity from similarity and evidence, reconstruct competing persistence criteria, and explain the branching problem without assuming a preferred criterion. Your answers reconstruct the supplied arguments; they do not report or score your own beliefs.
If apparent memory alone guaranteed identity with the event's subject, the report would establish persistence.
The memory-based identity inference requires that strong sufficiency claim.
Apparent memories can be misleading or copied in the thought experiment.
A person accurately reports an apparent memory of an earlier event.
Recall the difference between a claim and its reason, between truth and validity, and between a possibility and an actual observation. This lesson uses those distinctions to reconstruct competing explanations. Assessment concerns accurate reconstruction of the supplied positions, not agreement with a philosophical belief.
| Term | What it means |
|---|---|
| Numerical identity | Being one and the same entity, rather than two similar entities. |
| Qualitative similarity | Resemblance in properties, which does not by itself establish numerical identity. |
| Psychological continuity | An appropriately connected pattern of memories, intentions, character, and other psychological relations over time. |
| Bodily continuity | Persistence connected with the continued life or organization of a body, as specified by a theory. |
| Branching | A hypothetical case in which a proposed continuity relation connects one earlier person to two distinct later candidates. |
| Persistence criterion | A proposed condition for an entity at one time to be the same entity at another. |
The question whether a later person is numerically identical to an earlier person asks whether they are one and the same individual across time. It differs from asking whether they resemble each other, share a personality, have the same social role, or are treated as the same account holder. A person can change many characteristics while remaining the same individual; two individuals can resemble each other closely without becoming one person.
Consider an invented case in which a musician changes profession, appearance, and preferences over twenty years. Those differences challenge a simple sameness-of-properties test. They do not by themselves establish that the earlier musician has ceased to exist. Conversely, two actors can imitate the musician's manner and biography without each being that musician. Similarity alone is too weak to settle numerical identity.
A persistence theory proposes what must connect the earlier and later stages. A separate evidential question asks how an observer could find out whether that connection holds. A photograph may be evidence of identity without being what makes the person persist. Losing the photograph need not destroy the person. Keep the criterion and the method of recognizing it separate when reconstructing an argument.
Another question concerns what matters practically in anticipation, responsibility, or care. A theorist might argue that some psychological relation matters even when numerical identity is unsettled. That is a substantive proposal, not permission to replace the original identity question without notice. State whether the passage is offering a persistence criterion, evidence for identity, or an account of practical concern.
Another way: An argument with a disputed bridge
Read the supplied position as a route from premises to conclusion. Keep the critic's reply beside the premise it challenges. An objection can accept much of a case while disputing one bridge; a successful objection to one argument need not prove the opposite theory.
A bodily approach connects persistence with the continuing body or living organism, although versions differ over exactly which continuity matters. A psychological approach emphasizes appropriately connected memories, intentions, beliefs, character, and other mental relations. These are families of proposals, not two slogans that settle every case as soon as a body or memory is mentioned.
Imagine an ordinary day in which a person wakes, remembers yesterday's plans, and continues them in the same living body. Both approaches can classify the case as persistence. Agreement on an easy example does not show their criteria are equivalent. To expose a difference, a thought experiment must describe a situation in which the relevant bodily and psychological relations come apart, then ask what each criterion implies.
A hypothetical transfer case might stipulate that a later person has the earlier subject's connected memories and intentions while a different bodily continuation remains elsewhere. The psychological proposal and bodily proposal may then identify different candidates, depending on their precise formulations. The exercise does not establish that such a transfer is technologically possible. It explores the implications of the stipulated criteria and their descriptions.
Do not caricature a bodily account as requiring every molecule to remain unchanged. Living bodies undergo change. Nor should a psychological account be reduced automatically to matching one autobiographical report. A theory can require causal and structural continuity rather than mere resemblance. A fair criticism must target the actual condition proposed rather than an easier substitute.
Memory is a natural place to begin because people use remembered experiences to connect their present lives with earlier events. But a simple criterion saying that a later person is the earlier person exactly when the later person remembers the earlier experience faces several questions. Are the memories genuine? Must every experience be remembered? Can identity survive a period with no direct recollection?
Consider three times. At the middle time, a person remembers a childhood event. At the latest time, the person remembers the middle period but no longer directly remembers the childhood event. Direct memory may connect the first pair and the second pair without connecting the earliest and latest stages directly. Numerical identity is transitive, so a criterion built only from direct recollection needs revision or defense in this pattern.
Psychological continuity can use overlapping chains rather than requiring one direct memory link across every interval. That proposal addresses the shape of the connection, but it also raises questions about which links count and how they are appropriately caused. A copied diary or a convincing false recollection is not automatically a genuine memory of having lived an event. Matching content alone does not settle the required relation.
There is also a circularity concern if genuine memory is defined as remembering one's own earlier experience and then used to define who the person is. A theory may seek a less question-begging description of the psychological relation. In an assessment, identify the concern precisely: the critic is asking whether the proposed criterion already assumes the identity it is meant to explain, not denying that ordinary memories are useful evidence.
Suppose a thought experiment stipulates one earlier person A and two later candidates B and C. B and C are distinct individuals, but each has the same proposed psychological-continuity relation to A. If the criterion says that relation alone is sufficient for identity, it yields A identical to B and A identical to C. By symmetry and transitivity of identity, B and C would then be identical, contrary to the stipulation that they are distinct.
This is a structural problem for an unrestricted sufficiency claim. The argument does not need to decide which candidate is more appealing. It shows that a relation capable of branching cannot straightforwardly function as numerical identity without further qualifications. A defender might add a nonbranching condition, revise the criterion, or distinguish identity from another relation important to survival.
Each reply has a cost that can be examined. A nonbranching condition makes the verdict about A and B depend partly on whether another candidate exists. A revised bodily condition shifts what the theory regards as decisive. A proposal focused on survival or practical concern changes the question being answered. These are possible theoretical responses, not automatically refutations or solutions.
To analyze a branching case, first list the stipulated relations. Then apply the proposed criterion to each candidate separately. Finally compare the resulting identity claims with the logical properties of identity. This order exposes the contradiction without assuming a view about souls, brains, or what future technology can do. The hypothetical's value is the pressure it places on the criterion's form.
A reliable record can help establish that a present person is connected to a past action. But an identification procedure and a metaphysical criterion need not be the same. A password may establish control of an account under a service's rules. It does not by itself prove numerical identity with the account's original user. Several people might know the password, or a legitimate user might forget it.
Likewise, a person's current resemblance to a past description can be strong or weak evidence depending on the circumstances. The philosophical point is not that ordinary identification is impossible. It is that the warrant should be stated at the level it supports. Evidence of continuity, institutional treatment, and the nature of persistence are different claims that may interact without collapsing into one another.
Questions of responsibility add further issues. Even if an individual persists, conditions such as knowledge, control, coercion, and changes in capacity may matter to an ethical judgment. Identity alone does not automatically settle every question of blame or obligation. Conversely, a theory about what practical concern should track must explain why its chosen relation matters rather than treating concern as a definition of numerical identity.
When a case mixes these questions, separate them in the response. State what the proposed criterion says about persistence, what the supplied evidence establishes, and which extra ethical or institutional premises would be needed for a recommendation. This keeps a philosophical exercise from silently becoming an unsupported legal or clinical judgment.
A counterexample to one memory criterion does not refute every psychological theory. A difficulty for one bodily criterion does not establish substance dualism. The conclusion should match the particular condition tested. If the objection depends on a possible branching case, identify that possibility claim as a premise rather than presenting the imagined setup as an observed event.
A useful final comparison states a shared easy case, a case where the criteria diverge, and the premise each defender would challenge in the objection. This creates a reviewable account of the debate. The learner need not choose a personal theory of the self to show that a proposed identity relation branches, that a memory argument is circular as formulated, or that evidence has been mistaken for a constitutive condition.
A story describes an explorer whose psychological records are copied into two later candidates, B and C. The narrative stipulates that both possess the same connected plans and apparent memories, while B and C are distinct individuals with separate future experiences. A narrator proposes that either copy's psychological continuity is sufficient to make that copy numerically identical to the original explorer A.
Apply the stated criterion without choosing a favorite. It yields A=B and A=C. Numerical identity's symmetry and transitivity then yield B=C, conflicting with the story's explicit distinctness premise. The problem concerns the unrestricted sufficiency criterion, not whether one copy seems more emotionally convincing.
A defender could add a nonbranching requirement, deny that the stipulated relation is genuine continuity, or argue that the story concerns a form of survival that need not be identity. Each response targets a different premise or changes the proposed conclusion. The exercise should record the difference rather than treating every response as an assertion that one particular copy is the original.
Finally, the story does not establish that actual psychological copying is possible or settle how a real institution should assign property or obligations. Those questions require further scientific and normative premises. What the bounded argument does establish is that the initial criterion, the duplicated relation, and the distinctness stipulation cannot all produce the proposed numerical-identity conclusions consistently. A good answer shows that dependency explicitly.
A close match in appearance or reported memories is not automatically numerical identity. A record can be evidence of persistence without constituting it. An objection to one proposed criterion should not be inflated into a verdict against every account of personal identity.
Locate the result being argued for.
The identity conclusion depends on the psychological sufficiency criterion.
This is the proposed conclusion. Its conditional wording preserves any assumptions the argument has not independently established.
Record the starting claim offered in support.
A later person is psychologically continuous with an earlier person in the supplied case.
This premise supplies the case or observation that the proposed bridge will use; it is not yet the whole conclusion.
Make the linking premise explicit.
If that continuity is sufficient for numerical identity, they are one person over time.
This is the proposed inferential connection. Assessing it requires the philosophical distinction named in its own wording.
Reconstruct the offered support before assessing the reply.
Statements 2 and 3 support statement 4.
The connection being proposed is: If that continuity is sufficient for numerical identity, they are one person over time. Mapping it makes the argument reviewable without declaring that premise true.
Locate the objection's immediate target.
The critic asks what happens if two later people share the same continuity. Target: statement 3.
The challenged commitment is: If that continuity is sufficient for numerical identity, they are one person over time. The reply should be evaluated at that point rather than treated as a personal criticism.
Locate the result being argued for.
The biological account attributes persistence under its organism-based premise.
This is the proposed conclusion. Its conditional wording preserves any assumptions the argument has not independently established.
Record the starting claim offered in support.
A later organism is biologically continuous with an earlier organism.
This premise supplies the case or observation that the proposed bridge will use; it is not yet the whole conclusion.
Make the linking premise explicit.
If personal persistence follows that organism's persistence, the person survives under this criterion.
This is the proposed inferential connection. Assessing it requires the philosophical distinction named in its own wording.
Reconstruct the offered support before assessing the reply.
Statements 4 and 3 support statement 2.
The connection being proposed is: If personal persistence follows that organism's persistence, the person survives under this criterion. Mapping it makes the argument reviewable without declaring that premise true.
Locate the objection's immediate target.
The critic asks whether psychological continuity can be lost while the organism remains. Target: statement 3.
The challenged commitment is: If personal persistence follows that organism's persistence, the person survives under this criterion. The reply should be evaluated at that point rather than treated as a personal criticism.
Locate the result being argued for.
The criterion identifies both successors with the earlier person, conflicting with their stipulated distinctness and identity's transitivity.
This is the proposed conclusion. Its conditional wording preserves any assumptions the argument has not independently established.
Record the starting claim offered in support.
A fictional copying case produces two distinct successors equally continuous with one earlier psychology.
This premise supplies the case or observation that the proposed bridge will use; it is not yet the whole conclusion.
Make the linking premise explicit.
Psychological continuity alone is sufficient for numerical identity, including when it branches.
This is the proposed inferential connection. Assessing it requires the philosophical distinction named in its own wording.
Reconstruct the offered support before assessing the reply.
Statements 1 and 3 support statement 4.
The connection being proposed is: Psychological continuity alone is sufficient for numerical identity, including when it branches. Mapping it makes the argument reviewable without declaring that premise true.
Locate the objection's immediate target.
The defender revises the criterion so continuity is not by itself sufficient in branching cases. Target: statement 3.
The challenged commitment is: Psychological continuity alone is sufficient for numerical identity, including when it branches. The reply should be evaluated at that point rather than treated as a personal criticism.
State what the objection can leave in place.
A fictional copying case produces two distinct successors equally continuous with one earlier psychology.
The critic may grant this other premise while disputing the targeted one. Rejecting one bridge does not automatically reject every observation or prove the opposite metaphysical theory.
Reconstruct the offered support before assessing the reply.
Statements 1 and 3 support statement 4.
The connection being proposed is: Psychological continuity alone is sufficient for numerical identity, including when it branches. Mapping it makes the argument reviewable without declaring that premise true.
Locate the objection's immediate target.
The defender revises the criterion so continuity is not by itself sufficient in branching cases. Target: statement 3.
The challenged commitment is: Psychological continuity alone is sufficient for numerical identity, including when it branches. The reply should be evaluated at that point rather than treated as a personal criticism.
State what the objection can leave in place.
Read the supplied argument and its critic. Mark only the two premises of the offered argument and choose its conclusion. The objection is important for evaluation, but it is not a premise of the original argument.
Underline the premises and circle the conclusion in the passage above.
The following is a supplied argument and objection, not a set of agreed philosophical facts. (1) If apparent memory alone guaranteed identity with the event's subject, the report would establish persistence. (2) The memory-based identity inference requires that strong sufficiency claim. (3) Apparent memories can be misleading or copied in the thought experiment. (4) A person accurately reports an apparent memory of an earlier event. Reconstruct it: enter both premise sentence numbers in ascending order, the conclusion number, and the premise number directly targeted by the objection. Evaluate the supplied reply's target, not your personal agreement with the view.
Find the offered starting point and bridge.
Premises: p, q.
List their printed sentence numbers in ascending order, keeping the objection separate from the offered support.
Find the result the argument asks its reader to accept.
Conclusion: c.
The conclusion is supported by the two offered premises, rather than offered as a reason for either of them.
Match the objection to its immediate target.
Target: t.
Ask which premise the reply disputes; disagreement with the overall result does not identify that premise by itself.
Complete the argument-role table using these fixed symbols: P = premise, C = conclusion, O = objection. Enter only P, C or O for each supplied statement. These symbols record its job, not whether it is true.
| Argument role | |
|---|---|
| The conclusion requires equating similarity with sameness. | |
| If qualitative resemblance were numerical identity, the resemblance would establish that they are one person. | |
| A future individual resembles an earlier individual in many traits. | |
| Two distinct individuals can share many qualities. |
(1) The theorist distinguishes survival-related concern from strict numerical sameness. (2) A theory values psychological continuity even in a branching case. (3) The practical dismissal depends on identifying prudential concern with identity. (4) If what matters for concern must always be numerical identity, branching continuity cannot matter. Construct the supplied reasoning. Draw supports from each premise to the conclusion, and challenges from the objection to its immediate target premise. This map records the proposed reasoning without asserting that its premises are settled.
This task has no paper form; do it on a device.
The following is a supplied argument and objection, not a set of agreed philosophical facts. (1) An identity proposal relies on direct memory links between each pair of stages. (2) If identity is transitive, gaps in direct memory cannot automatically break every indirect identity chain. (3) The proposal needs to address connected versus continuous psychology. (4) The revised account uses overlapping psychological links rather than direct recall of every stage. Reconstruct it: enter both premise sentence numbers in ascending order, the conclusion number, and the premise number directly targeted by the objection. Evaluate the supplied reply's target, not your personal agreement with the view.
Analysis of personal identity through change: first premise p; second premise q; conclusion c; objection target t.
The following is a supplied argument and objection, not a set of agreed philosophical facts. (1) An archive simulation copies a fictional person's memories into two separate successor characters. (2) The reviewer distinguishes the copies' shared contents from their distinct subjects. (3) The simulation exposes a tension between resemblance and numerical identity. (4) If both copies being alike made them numerically one, their distinct locations would not matter. Reconstruct it: enter both premise sentence numbers in ascending order, the conclusion number, and the premise number directly targeted by the objection. Evaluate the supplied reply's target, not your personal agreement with the view.
Analysis of personal identity through change: first premise p; second premise q; conclusion c; objection target t.
Lesson test: one question per skill, one attempt each, no hints. Your answers are checked when you submit.
The following is a supplied argument and objection, not a set of agreed philosophical facts. (1) Those psychological links suffice for numerical identity even when two distinct successors have them. (2) The defender denies that the stipulated links suffice for identity in a branching case. (3) The case stipulates two numerically distinct successors with equally strong psychological links to one earlier person. (4) The unqualified criterion identifies both successors with one earlier person and therefore conflicts with their distinctness. Reconstruct it: enter both premise sentence numbers in ascending order, the conclusion number, and the premise number directly targeted by the objection. Evaluate the supplied reply's target, not your personal agreement with the view.
Analysis of personal identity through change: first premise p; second premise q; conclusion c; objection target t.
Without rereading, distinguish numerical identity from similarity and evidence, reconstruct competing persistence criteria, and explain the branching problem without assuming a preferred criterion. State a premise the objection can accept and the different premise it directly challenges.
16. Complete the objection analysis, step 3
A fictional copying case produces two distinct successors equally continuous with one earlier psychology.
The critic may grant this other premise while disputing the targeted one. Rejecting one bridge does not automatically reject every observation or prove the opposite metaphysical theory.