"Voodoo Doll Louvre" by Jastrow licensed under CC BY 2.5 cropped by Nick Byrd

Personal Identity: Taking Vantage Points More Seriously

Suppose the following about persons.

    1. Persons have sensory experiences from certain vantage points
    2. Persons’ have psychological states
    3. Sensory experience and psychological states can vary as a function of vantage point

How does this effect personal identity? To put it briefly, it would mean that for one person to be identical with another, then (given Leibniz Law, strictly enforced) the persons would have to be identical according, at least, to the following variables:

    1. Sensory experience and psychological state(s)
    2. Vantage point(s)


Persons as Information Gatherers. The impetus of this view of personhood is the idea that persons are, among other things, information-gathering beings. Consciously or not, they ‘gather’ information—and sometimes the information is stored. Here’s the kicker: gathered information—whether it is being attended to or not, whether presently in the field of consciousness or stored from a past field of consciousness—is a necessary property of personal identity.

Information Varies Depending Upon Vantage Points. From this claim about persons I add another: persons, necessarily, collect information from a single location in time and space—henceforth, this location will be called a spatiotemporal vantage point. Persons cannot collect information from multiple locations in time or in space; they also cannot collect information from ‘outside’ of space or ‘outside’ of time—whatever that would mean.

Having described spatiotemporal vantage points, I add another claim: information gathered from a spatiotemporal vantage point is unique to that point. Thus, information from two non-identical spatiotemporal vantage points is non-identical. When I gather info from spatiotemporal point A and you gather info from non-identical spatiotemporal point B—even if we are gathering info about the same event—our info is not identical.

Camcorder Analog. A useful analog for the idea of personhood hitherto outlined is a digital camcorder. It gathers visual and auditory information and stores is on some sort of memory device. The information that is gathered is unique to the spatiotemporal vantage point from which it was gathered. If two camcorders gathered footage of the same event, but from different times and/or spaces, then the footage would not match — this could easily be verified by watching the footage.


There are a couple benefits to this claim about personal identity:

    1. Avoids location problems. Problems follow is either (i) location is not a property or (ii) location is a property. My commitment to vantage points allows the benefits of a location-like property by smuggling in the concept vantage point (which involves location). Indexing vantage points allows us to pick out one person from another based on something like location, but less problematic than location simpliciter. So two persons are different if they occupy different locations, but one person does not become a new person every time they occupy a new location because their locations share something in common: a chain of connected vantage points. Also, this view makes co-location impossible. If two identical persons occupy the same vantage point, then there is only one person at said location.
    2. It’s intuitive. The main hesitation with many theories of personal identity is that they seem counter-intuitive — sometimes so much that comprehensive revisions to language and social practice would be required were the theory to be true. My commitments concerning personal identity allow persons to be picked out in ways that are not uncommon for philosophers and non-philosophers alike. Think about duplication. My students often tell me that duplication results in two new people because, after all, once the two persons begin living separate lives (and occupying different vantage points), then their identities deviate from one another.

There might also be concerns:

    1. It’s counterintuitive. If I had not chosen to do X (or not had the vantage point Y, or not had the psychology Z), then I would be another person! This means that whenever I actualize one of a few possible options, I shape my person in a sort of irreversible way. This might offend some people’s intuitions. I find it rather palatable. Indeed, I think this dovetails nicely with philosophical and empirical work on character formation, habit, implicit association, etc. But more importantly, a counter-intuitive result is not devastating. My goal is not to satisfy everyone’s intuitions — I’m not sure that’s a realistic goal. Rather, my goal is to make sense of many common judgments and provide explanatory power. This view allows for that.
    2. [Your suggestion here]


If what has been outlined is true of personal identity, then a few implications follow:

  1. Personal duplication is impossible: once two persons—whether the product of duplication or not—are gathering information that is exclusively available from each non-identical spatiotemporal vantage point, then the persons are non-identical. This conclusion relies on Leibniz’s law being enforced such that when person 1 gathers information X and person 2 gathers information Y, the two persons’ non-identical information deems them non-identical. This means that personal duplication thought experiments will have much less to offer the domain of personal identity.
  2. Neither the somatic or the psychological view of personal identity are independently sufficient. Brains (or psyche’s) cannot sufficiently account for identity since the brain relies on the body to gather information and the content of gathered information is a direct consequence of the spatiotemporal location of the body that gathered it. So, both the body (its ‘stuff’ and its spatiotemporal location) and the brain (or the psychological content) are necessary elements of personal identity. In this way a person is, among other things, both a physical thing at which one can point—”That guy over there!”—as well as an informational thing that can be ‘picked out’—”The guy with ‘such-and-such’ mental content who occupied such-and-such vantage points.”
  3. Neither internalism nor externalism about personal identity are right. If both internal states and environmental features like sensory input and vantage point are part of personal identity, then personal identity is not entirely an internal or entirely an external phenomena. It is both. This strikes me as a happy conclusion since many debates strictly internalist and strictly externalist views seem to be distinguishable with counterexamples. So, it seems that a principled middle view is probably best. The present views allows one to hold a principled middle view.

Image credit: “Voodoo Doll Louvre” by Jastrow licensed under CC BY 2.5 cropped by Nick Byrd

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Nick Byrd

Nick is a cognitive scientist at Florida State University studying reasoning, wellbeing, and willpower. Check out his blog at byrdnick.com/blog

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So is a zygote a person?


Janice: if a zygote is a person, then so is a bumblebee or an ant. These are at least as likely to have a psychology as a zygote.


I am not of the opinion that zygotes could be persons. And I do not think they have rights to a woman’s body.

Mark Pharoah

As a general point… I think you need to clarify what you mean in your use of the term ‘psychology’. “Persons have psychology” is too broad or vague to mean very much. What is the psychology that they have?

Mark Pharoah
Point 1 – “Folk psychology” definitely helps me get a better idea of where you are coming from. Point 2 about personal identity – To identify a triangle we might say that it has 3 sides: ex1. Consequently, two triangles might be identified as triangles by observing that they have 3 sides. But we can only say of the two triangles, that they are similar. i.e. they are not identical. ex2. Two triangles that occupy the same spatio-temporal place, can be said to be identical. They have 3 sides; and those 3 sides are of the same length; and those… Read more »