Discovery Seminar 175555/UE 141 M – Fall 2008 Solving Crimes using Referent Tracking On ‘definitions’ September 17, 2008 Werner CEUSTERS Center of Excellence in Bioinformatics and Life Sciences Ontology Research Group University at Buffalo, NY, USA

What is a definition ? I asked Google: “define: definition” a concise explanation of the meaning of a word or phrase or symbol (wordnet.princeton.edu/perl/webwn) a statement of the meaning of a word or phrase. (en.wikipedia.org/wiki/Definition) "Definition" is the first single from Black Star's eponymously titled 1999 album (see 1999 in music). It is produced by Hi-Tek, who samples "The P Is Free" by Boogie Down Productions for the track's beat. ...(en.wikipedia.org/wiki/Definition) Definition was a Canadian television game show, which aired on CTV from 1974 to 1989, and filmed at its flagship studio of CFTO-TV in Scarborough, Ontario (en.wikipedia.org/wiki/Definition (TV series) Statement that expresses the essential nature of a data element and permits its differentiation from all other data elements. (144.53.252.30/AUSSTATS/abs@.nsf/Latestproducts/4527.0Appendix12006) A formal, specific, and exact specification. (www.chemie.de/lexikon/e/Kilogram) A dictionary-style statement that describes the concept designated by a term. (www.translationbureau.gc.ca/index.php) A step in the marketing research process that involves a clear statement of the topic to be studied. (www.prenhall.com/rm_student/html/glossary/i_gloss.html) Which are relevant in our context ?

What does it mean ‘to define something’ ? ‘dog’ Dog-ness

What does it mean ‘to define something’ ? Dog-ness Under what circumstances am I allowed in my community to use the word ‘dog’ to denote some thing in reality ? ‘dog’

What does it mean ‘to define something’ ? What are the essential characteristics that distinguish dogs from other things ? Dog-ness ‘dog’

What does it mean ‘to define something’ ? Dog-ness How to determine whether the thing of which this picture is taken is a dog ? ‘dog’

Examples for each type of definition Appropriate usage of a word ‘girl’ – ‘chick’ Essential characteristics distinguishing types from other types ‘death’ – ‘alive’ Essential characteristics for something to be of a type for a human: head separated from rest of the body 2 1 3

How can we know what dogs ‘really’ are ? ‘Dog-ness’ Dog-ness generic specific ‘dog’ Human understanding and communication First-order reality

In what way do the corner-denotations interact ? Scientific discovery ‘Dog-ness’ Dog-ness generic specific Case study Convention Convention ‘dog’ Convention Human understanding and communication First-order reality

The right sort of science

What is a good definition ? Is ‘a good definition gives an if-and-only-if condition for when an object satisfies a definition’ a good definition ? No ! What if your teacher gives you an if-and-only-if condition for an object to be a dog? Is your teacher then a good definition ?

One type of good definitions: Aristotelian definitions Better a good definition is a definition which gives an if-and-only-if condition for when an object satisfies that definition One type of good definitions: Aristotelian definitions An X is a Y which … A killing is an act which … An act is a process which … … ?????

The structure of reality mammal dog horse cat hound