On Philosophy

September 21, 2006

Constitution and Instantiation

Filed under: General Philosophy — Peter @ 12:35 am

People, art, minds, water; all of these things can be considered abstractions that are above and beyond the fundamental physical components of the world. If indeed the physical universe is completely causally closed then each of there kinds must be a natural kind, which for our purposes here simply means that membership in each of these categories is determined by some set of properties and that all of an object’s properties are determined by its fundamental physical constituents / properties, or, in other words, if two objects are exactly physically alike then they have all the same properties*.

Given this, there are two ways some collection of the fundamental physical stuff can relate to one of these more abstract categories, constitution and instantiation. If a collection of fundamental physical stuff has all the properties required to be a member of some abstract category, and it has those properties regardless of the contents of the rest of the world, then it is instantiating that abstraction. For example, two hydrogen atoms bonded to an oxygen atom have all the properties required to be water, and they have them no matter what the rest of the world contains, therefore they are instantiating water. On the other hand, a collection of fundamental physical stuff constitutes some abstract kind if it has all the properties required to be that kind of thing, but only in virtue of some other collection or collections of fundamental physical stuff or its relationship to them. For example, a carved block of stone only constitutes a specific work of art, since it is art only because there are people who appreciate it as such. A more technical way of describing the difference between instantiation and constitution is to say that a collection of fundamental physical stuff, h, instantiates an abstract kind, X, if and only if it is necessary truth that h is an X, and that h constitutes X if and only if the fact that h is an X is a possible (contingent) truth.

Why is this difference important? Well in the case of instantiation is customary to say that if h instantiates X that h is identical (or, properly speaking, dependentical) to X. Now, let us turn to the case of an individual person. Does a person’s body (including their brain) constitute or instantiate that person? We will say that something is a given person if it has some specific set of mental (psychological properties), to reflect the fact that a person’s physical form doesn’t define who they are, but that their mind does. Given that we are materialists, we must conclude that the body instantiates the person (since to the best of our knowledge the mental / psychological features depend only on the fundamental physical stuff that makes up the brain). Thus we conclude that a person is identical (dependentical) with their physical body.

Why have I even bothered to illuminate the difference between constitution and instantiation? Because some philosophers defend both materialism and the idea that the body constitutes the person. They are able to do this consistently by denying that all properties depend solely on the physical contents of the world. In addition they claim that the property of being a specific individual is one of these properties, and thus that the body only constitutes the person, since there are possible words where that body (in exactly the same physical state) is not that individual. However, if we accept that the physical world is completely causally closed, an assumption that is necessary if one wants to call oneself a materialist, then the histories of worlds that are physically identical are also identical. This in turn means those properties that don’t depend exclusively on the physical contents of the world are epiphenomenal.** Thus accepting that the property of being an certain individual is one of these properties is to say that the property of being a specific person is effectively meaningless, since it has no impact on the course of events. I consider this to be absurd, and thus reject the possibility that there are such epiphenomenal properties, and thus conclude that claiming that the body only constitutes a person and that materialism is an accurate description of the world is incoherent.

* Some would object to this on the grounds that “historical” properties exist, such as the property of being made in China, which cannot be deduced from the physical properties of the object. What this objection misses is that an object’s history is equally as physical as its mass, it is simply not revealed by observations made at a single point in time. We could even describe the object with an extended temporal dimension (what the historical property is really a property of) as being made of the objects that existed in each instant of time. Under this view the objects at each instant would constitute the object + extended temporal dimension, which explains why none of the object-instants necessarily have the historical property in question, even though their collection does (for example, the property of being moved from New York to California cannot be had by any object-instant).

** We conclude they are epiphenomenal because there are worlds that are physically the same but differ in some of these properties. And since these worlds have the same histories we can conclude that the property is not the cause of any physical property, and hence that it is epiphenomenal.



  1. Verbs, not nouns!

    Let’s say there’s me and there’s something with all the same physical properties as me. How do we tell the difference? We can’t say, Oh, well you’re the one with the same atoms as when you were born, because my atoms have all come and gone by now. Instead we have to say, you’re the one who is part of a continuous process, whereas your teleporter clone or whatever, is not part of this same continuous process.

    Verbs, not nouns!

    Trying to find nouns in a world of verbs is the great mistake of Western metaphysics.

    Comment by Carl — September 21, 2006 @ 1:00 am

  2. (I should clarify that I do agree that atoms are real; I just think they’re only rarely useful for defining the identity of something used by humans. Instead, we must use our subjective and collective telos to assign appropriate labels.)

    Comment by Carl — September 21, 2006 @ 1:37 am

  3. No, there would be no difference, you would be identical, since if you were exactly the same you would have the same spacial position, ect. Then apply Leibniz’s law.

    Comment by Peter — September 21, 2006 @ 2:11 am

  4. My position is part of my identity?

    Then my rebuttal is Einstein’s Theory of Relativity: There is no Newtonian Absolute Space.

    The point I’m getting at is that I know I’m me and not something else that shares a lot of properties with me, because my current existence was caused by my past existence in a direct, organic way, whereas my teleporter copy was not caused by the existence of my biological processes, but by something else.

    Comment by Carl — September 21, 2006 @ 2:52 am

  5. um, you can still specify position under relativity with percision, you just need to include a frame of reference.

    Comment by Peter — September 21, 2006 @ 3:36 am

  6. Also this post has nothing whatsoever to do with identity over time, which seems to be your concern in your comments.

    Comment by Peter — September 21, 2006 @ 4:41 am

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