Concepts as Action-Oriented as 'Search'

Muhammad Aurangzeb AhmadDepartment of Computer Science and Engineering

University of Minnesota

mahmad@cs.umn.eduhttp://www.tc.umn.edu/~ahma0089/

Outline

● Background Information● Clark-Prinz Contra Fodor● Concepts, Actions and Search Engines● Networks and Search Engines● Concepts: Networks of Networks● Putting it all together● Criticism● Conclusion

Background

Major Issues (SEP)

Ontology of Concepts Structure of Concepts Empiricism and Nativism about Concepts Relation between Concepts and Natural Language Concepts and Conceptual Analysis

Major Theories / Paradigms about Concepts Classical Theory:

Concepts have a definitional structure Conceptual Atomism

No semantic structure

Major Theories about Structure

Prototype Theory Concepts have a probabilistic structure and have to

satisfy a sufficient number of conditions. Theory Theory

Concepts are like scientific theories and are defined in terms of one another.

Exemplar Theory Concepts are represented as examples of categories

Proxytype Theory Concepts are copies of perceptual representations in

long term memory and can be activated in working memory

Clark-Prinz Contra Fodor

Fodor To possess a concepts is "about being able to think

about the things or states of affairs in question." Clark & Prinz

Concepts are (mostly) for acting. “We have representations in order to act, and the way

we act, on the basis of our representations, may have some impact on what they mean.” (Prinz, Clark 2004)

The Frame Problem

● Given a massive reservoir of data how does one find “the right stuff (information, data) to consider (update, or use in reasoning) at the right time.” (Andy Clark 2002)

● Given that one's knowledge base is potentially immense how does one determine which features of the world to attend to.

● Even the features of relevance will bring up another problem.

Search Engines

The Problem Faced by Search Engines Massive repository of data and a query. The set of

documents that are superficially relevant to the query are literally in tens of millions.

Solution: Syntactical approaches work for small databases but

not for global search in large databases. Divide the large database into smaller units but this

assumes that one already knows what the boundaries of the sub-domains are.

Search Engines: Google et al.

Information about information is still information. Instead of looking at the content look at the links

between the pages. Search based on links instead of purely on the

content is immensely more powerful Example:

Do a dumb syntactical search – k pages Expand the links and get the linked pages Compute the rank of the pages The ones with the higher rank are more relevant

Example: Simplified PageRank

Assume a Uniform Distribution of Pages Pages: a, b, c, d Assume uniform distribution initially

PR(a) = PR(b) + PR(c) + PR(d) After reassignment

PR(a) = PR(b)/2 + PR(c)/1 + PR(d)/3 Generalization

PR(u) = ΣPR(v)/N, v in B

b c d

a

bc

d

a

Clark's Approach

The Human Cognitive System is doing something similar when its solving the frame problem.

Use Second Order Information Objections

Isn't this circular? Encoding Distributed vs. Central Verification

Beyond AC: More on Concepts and Search

In the case of the webpages there is content but we choose to (mostly) ignore it.

What does content constitute when one is discussing human cognition?

Why stop at second order information? When you have a set of returned features you look at

not just the returned features and their rankings but the 'links' between the features

The result you get can be thought of as one mechanism about how agents like us would possess concepts

Concepts and Search

Before

After

Similarities with other theories

Theory-Theory: Concepts are defined by their role in a larger 'theory' of

things. Prototype Theory:

Concepts have a probabilistic structure and have to satisfy a sufficient number of conditions.

Instead of Conditions now you have graph similarity. Exemplar Theory:

Exemplars are just the representations (graphs) which are most likely to be returned by the query about the category.

Issues: Representation & Prop. Attitudes

Why are certain objects considered to be more representative of a category as compared to others?

How can we have certain propositional attitudes without having relevant mental representations? Example: Drunk pink elephants don't fly in space

shuttles.

Miscellaneous Issues

Problem of Communication If the concepts that people have do not always

correspond with one another then:• How can people possible communicate with one another?• Does it even make sense to say that they have the same concept?

Concept Pragmatism• What matters that people are able to act?• Sufficient similarity between their respective 'concepts

How to deal with Concept Hierarchies? Subcategories are not necessarily subgraphs Think of these as collapsing Nodes

Issues: Problem of Composability

Some concepts are not simply sum of their parts. Example: People associate certain traits with fish

and other traits with pets. However pet fish conjures up an different image such that: Pet Fish ≠ Pet + Fish

When dealing with concepts which appear to be composed of other concepts people use other background knowledge to make sense of the concept.

Issues: Problem of Composability (ii)

Pet Fish

Common Traits

Pet Fish

Criticism

How do we deal with cases that involve: Abstract Knowledge - Numbers Logical Operatives

Conclusion

A complementary theory of concepts Concept Empiricism Structural Pluralism Concept deployment is an online process