Personal Identity

What are the two main types of identity?

Numerical identity and qualitative identity.

What is numerical identity?

The strict sameness of an object or person over time. If A is numerically identical to B, they are the exact same entity.

What is qualitative identity?

When two things share all the same properties but are not necessarily the same object (e.g., two identical phones are qualitatively but not numerically identical).

What determines the identity of a material object according to John Locke?

A material object remains the same only if its atomic composition does not change.

What determines the identity of a living thing according to John Locke?

A living thing remains the same as long as it continues to participate in the same continuous life process, even if its physical matter changes.

How does Locke define a person?

A person is a “thinking, intelligent being that has reason, reflection, and self-awareness across different times and places.”

According to Locke, what makes a person the same over time?

A person remains the same if they have the same consciousness, meaning they can remember past experiences and recognize themselves as the same person.

How does memory contribute to personal identity?

Memory serves as a bridge between different stages of consciousness, ensuring continuity of personal identity even during unconscious states (e.g., sleep, coma).

What problem does permanent amnesia pose for Locke’s theory?

If identity depends on memory, then a person with amnesia would no longer be the same person.

What problem does false memory pose for Locke’s theory?

If someone has a false memory of an event, are they still the same person they think they are? This questions memory’s reliability in defining identity.

What is perfect identity, according to Reid?

Perfect identity requires continuous, uninterrupted existence without change.

What must the self be, according to Reid?

The self must be indivisible, non-physical, independent of consciousness, and have an unchanging soul.

How does Hume define knowledge?

Knowledge is based on experience (empiricism).

What does Hume argue about personal identity?

Identity is an illusion—we mistake a collection of experiences for a continuous self.

Why do people believe in an unchanging soul, according to Hume?

We invent the idea of a soul to explain continuity, but in reality, the self is just a bundle of experiences that constantly change.

What is the main belief of the Advaita Vedanta tradition regarding identity?

There is no individual self—identity is an illusion, and reality is a unified whole.

How does the main belief of the Advaita Vedanta tradition compare to Hume’s Bundle Theory?

Both reject the idea of a stable, permanent self.

How does Parfit define identity?

Identity is a strict one-to-one relation—A and B are the same only if there are no differences between them.

What is the difference between identity and continuity?

Identity requires exact sameness while continuity means having a strong psychological connection (but not necessarily sameness).

What is the brain fission thought experiment?

Imagine a person’s brain is split into two and transplanted into two different bodies. Which one is the original person?

What conclusion does Parfit draw from the brain fission thought experiment?

Personal identity doesn’t matter—psychological continuity does. If both brain halves continue the person’s thoughts and memories, identity is not a simple yes/no question.