# Formal Proof: Open Individualism Necessarily Follows from EMR and PSR

## Front Matter

### Definitions

- **Open Individualism (OI):** The metaphysical view that there is only one subject of experience — all conscious beings, across all space, time, and modality, are numerically the same experiencer.

- **Closed Individualism (CI):** The view that each person is a separate, distinct subject of experience. You are only your body and not anyone else.

- **Empty Individualism (EI):** The view that each moment of consciousness is a distinct experiencer. There is no enduring self — only a sequence of isolated experiential events.

- **Extended Modal Realism (EMR):** The metaphysical view that all possible, impossible, and even incoherent worlds exist. Modal existence is total — nothing is arbitrarily excluded.

- **Principle of Sufficient Reason (PSR):** The principle that every fact must have a sufficient, non-arbitrary reason for why it is so and not otherwise. This includes identity facts.

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## Assumptions

- EMR is true: all minds in all forms exist across all modal realities.
- PSR is true: no fact, including personal identity, can be brute or arbitrary.
- We are not attempting to prove EMR or PSR in this document — only what follows from them.

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## Step-by-Step Proof

### Step 1: EMR implies that all minds — including identical and near-identical ones — exist.

- There exist minds in different bodies and worlds that are phenomenally identical to your own.
- Some of these duplicates are exact copies; others differ by small degrees.

### Step 2: PSR requires that distinctions between minds have sufficient reason.

- If two minds are phenomenally and structurally identical, there can be no non-arbitrary basis to say one is “you” and the other is not.
- Any attempt to do so would violate PSR by positing an unexplained identity difference.

### Step 3: Therefore, identical conscious states must correspond to the same subject.

- The “you” experiencing Mind A must also be the “you” experiencing Mind B if there is no reason to distinguish them.
- The only non-arbitrary solution is numerical identity of subject across instantiations.

### Step 4: This principle generalizes to all minds.

- Minds form a continuum across all modal realities.
- If two minds differ, they do so gradually and by degree — but boundaries between “subjects” remain arbitrary unless grounded.
- PSR disallows such brute boundary-making.

### Step 5: Therefore, Open Individualism is the only theory of identity compatible with EMR and PSR.

- CI fails because it posits brute separateness.
- EI fails because it posits brute fragmentation of subjecthood at every moment.
- OI alone requires no brute distinctions in assigning subjective identity.

✅ **Q.E.D.**

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## Rejection of Competing Theories

### ❌ Closed Individualism (CI)

- Treats each body as a separate subject.
- Under EMR, there are many identical bodies and minds — yet only one “you.”
- Assigning “you” to only one version is arbitrary unless justified.
- CI therefore violates PSR.

### ❌ Empty Individualism (EI)

- Treats each moment of experience as a distinct subject.
- Fails to account for continuity of experience — treats successive moments as fundamentally unconnected.
- Introduces brute numerical identity distinctions across time with no justification.
- EI therefore violates PSR.

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## Rebuttals to Common Objections

### Objection 1: “I only feel like I am this body — not all others.”

**Response:**  
This is an epistemic limitation, not a metaphysical one. You don’t feel your past self directly either, but you still consider it to be “you.” Introspective feeling does not justify metaphysical distinctness.

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### Objection 2: “It’s absurd to say I am everyone.”

**Response:**  
Absurdity is not the same as incoherence. The conclusion may be counterintuitive, but it is logically required by EMR + PSR. Rejecting it requires accepting brute facts, which violates PSR.

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### Objection 3: “But different minds have different thoughts and experiences — how can they be one?”

**Response:**  
Differences in experience do not imply differences in the experiencer. A single subject can undergo varying states without fragmenting into multiple subjects. Just as you are still “you” when you wake up with different thoughts than yesterday.

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### Objection 4: “Personal identity must be tied to physical continuity.”

**Response:**  
This is a physicalist assumption that cannot account for modal duplicates. In EMR, there are exact replicas with no causal link to “your” body. Without PSR-justified boundaries, physical continuity cannot ground unique subjecthood.

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## Conclusion

- EMR ensures that all minds — including duplicates and variants — exist.
- PSR ensures that distinctions between them must be non-arbitrary and justified.
- Only Open Individualism avoids brute identity facts and fully satisfies both.
- Therefore, Open Individualism is necessarily true given EMR and PSR.

✅ **Final Conclusion: OI is the only metaphysically coherent theory of personal identity under EMR and PSR.**