Saturday, August 6, 2011

The Great Chain of Being as Conceptual Structure

This is a bit of mildly technical cognitive science from the archives. It's relevant to a current run of posts about ontology.
Lakoff & Turner (1989) have used a cognitive account of the Great Chain of Being in the analysis of proverbs. I’d like to elaborate on the commonsense structure they call The Nature of Things and suggest an extension.

The Assignment Relation

Consider the table below (adapted from Bloom and Hays, 1978), which moves up the Great Chain. The object in the left-most column is considered to consist of an ASSIGNMENT between the object immediately above it and the object to its right. The general idea is that ontological structure is a pattern of assignment relations.

1) substance
2) thing form
3) living being (plant) vegetative soul
4) animal sensitive soul
5) natural person rational soul
6) social person role

The left-hand column is recognizably the Great Chain and, at this level of argument, rows 1, 2, and perhaps 6 are relatively unproblematic. But what about those souls in lines 3, 4, and 5?

[In the annoying manner of math texts, I leave it as an exercise for the reader to determine whether or not, and if so, just how, juristic persons (corporations) are to be incorporated into this ontology, perhaps as types of social person. I note that this particular issue is under dispute in American politics.]

The first thing to be said is that they are there in Plato and Aristotle and continue in the Western intellectual tradition into the seventeenth century. The second thing to be said is that they are obviously essences, the conceptual purpose of which is to account for the behavior of the beings possessing them. If a plant grows, then, by [the metaphor mapping] EVENTS ARE ACTIONS, it is the vegetative soul that is causing the growing. Things do not have souls and so cannot grow; plants do have them and so can. Similarly, if a dog is sniffing the air and following a scent, it is the sensitive soul which is the source of agency. And so it is for the natural person, speech, and the rational soul.


Essences

I think, in fact, that we need more than EVENTS ARE ACTIONS to account for these inner agents. I believe we need the notion of an essence. Lakoff and Turner have some comments on that (p. 148). I’m rather fond of a notion that the essence of a thing is to the thing as the mathematical construction of a geometric figure is to a drawing of that figure. For one thing, rather than (implicitly) treating the concept as a universal (though, for all I know it may be, though I doubt it) this conception situates the concept of essence in a cultural context (ancient Greece) where folks were struggling to formulate the concept of an essence and to then, systematically, set out to explicate the essences behind everything.

In this construction, the mathematical construction is considered to be the essence of the physical drawing. Given some such notion, if you substitute, say a bed for the drawing of a triangle, you can then go looking for something what stands in relation to the bed as the geometric construction does to the triangle. Whatever it might be, we’ll call it the bed’s essence and so we’re off looking for essences for everything. So that’s part of the story I’m proposing.

Case Roles

The other part of the story has to do with case roles and is part of the explication of how EVENTS ARE ACTIONS yields these various souls. In ordinary circumstances, what roles are generally available to objects of a given type? Thus there is a set of actions, such as speaking and arguing, where only humans can take the agent role. There is another set of actions, such as look or run, where only animals (or humans) can take the agent role. Another set events, such as grow and die, requires living beings (or animals (or humans)).

It is also worth explicitly pointing out that the logic of assignment structure means that humans are animated by all three souls. And that takes us into the territory Lakoff (1996) looked at in his essay on the self.

Inheritance

Beyond this, I note that this ontological structure is explicitly a structure of inheritance, but it is “orthogonal” to the inheritance in the ISA paradigms of AI knowledge representation. In that sort of inheritance, dogs inherit all the properties and capacities of animals (for a dog is an animal) and have, in addition, the unique properties and capacities of dogs, rather than cats or gerbils. In like fashion, collies inherit all the properties and capacities of dogs, and lassie all the etc. of collies. The assignment relation functions at the root of such ISA paradigms. The animal node inherits the properties and capacities of plants (life & growth) via assignment just as the plant node inherits the properties and capacities of things via assignment. It is this inheritance via assignment that gives The Nature of Things its conceptual punch.

Now, I would imagine proverbs exist in cultures which don’t have an explicitly formulated Great Chain simply because they don’t have terms for plant and animal (Berlin, 1992). They can handle the required cross-domain mappings in the absence of well established assignment relations. It makes one wonder whether the repeated use of proverbs in a culture eventually leads to the explicit formulation of a Great Chain.

Other Ontologies: Mechanical Objects

The assignment relation, however, can underlie ontological structures other than the standard Great Chain. A number of years ago I was thinking about knowledge representation in the domain of computer integrated manufacturing. Note that, in doing this work I was not particularly concerned about modeling how people really think about a certain set of objects. I was mainly interested in understanding what kind of knowledge a computer system needed in a manufacturing environment in order to drill, grind, weld, assemble, etc. mechanical devices. So the example is deliberately artificial—but then, is not all language artificial when the rules committee originally decided to do it this or that way? In any event, I constructed a chain that went something like this (Benzon 1985):

1) material
2) object surface and shape
3) assembly connectivity
4) mechanism articulation
5) engine power

First some comments about this particular ontology. I found it useful to differentiate between surface & shape (2) because there are operations one performs on a surface (painting, plating, cleaning, etc.) more or less independent of its shape. An assembly consists of a number of (primitive objects or other assemblies) plus a connectivity structure, X is connected to Y is connected to Z and Q, etc. I consider this connectivity structure to be distinct from, though often congruent with, the standard part-whole notions.

For example, consider a chair. If you are just going to use a chair, either for sitting or fending off lions, you certainly need to attend to its parts, but not in any great detail. You need not even notice nails and screws much less enumerate them and understand their exact locations. But if you are going to construct a chair, then you need a complete and exact enumeration of parts and you need to impose some ordering on those parts such that you can assemble them into the chair. This requirement means that a connectivity structure must be more than an exhaustive parts list. A connectivity structure is, in effect, a projection of an assembly plan onto the parts set (as a soul in the Great Chain is the projection of actions onto an abstract actor).

An assembly with moving parts brings another considerations into play. For one thing, the parts cannot interfere with one another. In the case of simple mechanisms, such as wheel barrows and pulleys, this is a rather simple consideration. But it is more complex when you are considering such things as clocks. Beyond this there is the causal relations between the parts: What do all these relative motions accomplish? Projected onto the assembled device, this is an articulation structure.

As for an engine, something needs to be said, but I don’t know quite what. In any event, the general principle should be, if not clear, at least emerging.

More generally, note that every object in this ontology “maps on to” the lower end (thing, form, and substance) of the standard Great Chain. Further, if we were to sketch out on ontology for physics and one for chemistry, those ontologies would map onto one locus in the GC, substance. However, it’s probably best to talk of such mapping with tongue firmly in cheek.

For example, while salt and sodium chloride are almost the same thing physically, conceptually they are quite different (Benzon 1991). Salt is defined directly in terms of color, texture, and, of course, taste. Sodium chloride is defined in terms of abstract objects such as electrons, protons, neutrons, electromagnetic force, etc. and the kinds of abstract actions those objects can perform. Finally, note that a physical “chunk” of salt can easily be pure salt, while that same physical “chunk” is unlikely to be pure sodium chloride, though it might be %99.99 pure. These sort of consideration lead me to doubt the wisdom of asserting that some ontology maps onto another is this or that way. Ontologies are different; that’s why we call them ontologies.

Back to the general discourse, note that there are cultures without mechanisms and, among those with mechanisms, there are cultures without engines or without knowledge of sodium chloride. In general, I think that the large-scale evolution of culture involves the creation of new ontologies, that is, new sets of assignment relations over new conceptual objects (cf. Benzon and Hays 1990). Perhaps the Kuhnian paradigm will turn out to be a coherent set of assignment relations over some set of objects.

References

Benzon, W. L. Ontology in Knowledge Representation for CIM. Center for Manufacturing Productivity and Technology Transfer, Rensselaer Polytechnic Institute. Report No. CIMNW85TR034, January 1985. Cf. Ontology in Knowledge Representation.

Benzon, W. L. Ontology of Common Sense. Handbook of Metaphysics and Ontology. Philosophia Verlag, 1991.

Benzon, W. L. and David G. Hays. The Evolution of Cognition. Journal of Social and Biological Structures 13, 297-320, 1990.

Berlin, B. Ethnobiological Classification. Princeton U. Pr. 1992.

Bloom, D. and D. G. Hays. Designation in English. In Anaphora in Discourse, edited by John V. Hinds. Edmonton, Alta.; Champaign, Ill.: Linguistic Research, 1978, pp. 1-68.

Lakoff, G. and Mark Turner. More than Cool Reason. Chicago: University of Chicago Press, 1989.

Lakoff, G. Sorry, I’m Not Myself Today: The Metaphor System for Conceptualizing the Self. In Spaces, Worlds, and Grammar, Gilles Fauconnier and Eve Sweetser, eds. Chicago: University of Chicago Press, 1996, pp. 91-123.

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