Personal Identity: A review of John Perry's work


Part of the Philosophy Papers series




The issue being dealt with in John Perry’s book, 'A Dialogue on Personal Identity and Immortality' is that of personal identity and the survival of the individual after death. This issue tries to understand how an individual can remain the same person despite all the changes they go through and if their survival is tied to their body. The answer to this question can have significant consequences. An example is in matters of justice where punishing an individual for their previous actions could be undermined if it is shown that they weren’t the same person. The part of the text I will be specifically looking at begins at the paragraph on page 12, starting with, “Let me appeal…” and ends with the paragraph on page 13 ending in “…kind of whole.”


The argument being put forward by the character Sam Miller is that an individual’s identity is something dependent on its entire existence. He makes this argument using three key points. First, identity cannot be found in the body, as it is constantly changing. Second, we are unable to grasp the whole identity of an individual. Finally, we can only judge an individual’s identity from its parts into a certain kind of whole.


Miller begins his argument by telling a story about a visitor and himself seeing the Blue River at one point of the day and then driving to another spot and pointing out another part of the same river. He describes the differences between these two parts of the river to emphasise that physically these different parts are very distinct from one another. He uses this story to illustrate that while the material aspects between the two parts of the river have changed, such as the colour, shape and level of pollution, it still remains the same river. This analogy is also meant to apply to an individual’s identity. While the physical aspects of an individual change over time, we don’t, therefore, say that this individual is a different person. Thus, their identity must be found in some other aspect of the individual.


Miller then continues his argument by emphasising that he only saw parts of the river and not the river as a whole. Thus, in reality, he wasn’t viewing the river’s identity, but just the two parts. Miller goes on by saying that this is not unique to rivers but applies to all objects. We only observe parts of an object in its existence through time, but never its whole existence. In this case, Miller never saw the whole river, and even if he did, the river’s changes through its existence would make Miller miss certain parts. This argument can also extend to the identity of individuals, specifically, their consciousness. We never observe the entirety of another individual’s conscious existence and, therefore, never observe their whole identity.

Miller finishes his argument by saying that the river he saw earlier and the river he saw later could only be the same river if there was a connection between the two parts. This connection is vital because it is what helps us to judge an object’s identity. Since we can’t view the whole object’s existence in time and space but only its parts, we then have to judge the connection between all of the parts we observe. It is only with this observation that we can judge an object’s identity as a whole. This can also be applied to the identity of an individual. As we only observe parts of an individual’s consciousness through time (and space), we have to judge a connection between these parts as encapsulating the individual’s whole identity. This connection Miller argues is the consciousness of the individual.

I find the author’s argument through the character Miller to be very interesting, but there are still some parts I have to disagree with. By appealing to an object’s existence in space and time as the source of its identity and continuance, it only produces further problems. My main objection is that breaking up an object into temporal parts doesn’t account for how these parts are broken up. If these temporal parts exist for a few moments, then they need an explanation for their own continuance. If they have no duration but are immediately going from one part to the next, then there is another problem. The sum of parts that have no duration can’t add up to something with duration. An infinite sum of zeros only adds up to zero. So, where did the author go wrong in his argument? I agree that identity can’t be based on the changing body. Something unchangeable about an object can’t be based on the parts that change. However, the second point about being unable to grasp the whole identity of an individual is where I think he has gone wrong. When we see the Blue River, we can know that it is a river and distinguish it from other rivers. We do not have to comprehend its entire existence through space and time just to identify it as being a unique river.

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