Concern with definition goes back to ancient Greece (1)

1. Concern with definition goes back to ancient Greece (1) Socrates: (470–399 B.C.) “Now one should do, Agathon, as you did, first describing who Eros himself is and what sort of character he has, and then going on to what he does.”1 Method: 1. categorize: Is Eros a god, a mortal or a daimon?2. characterize: Is Eros good? Bad? Beautiful?3. describe behavior: Is Eros helpful to men? 1. Plato, Symposium, edited by C.J. Rowe, Aris & Phillips Classical Texts, 1998, p.77

2. Concern with definition goes back to ancient Greece (2) Socrates: (470–399 B.C.) “Now one should do, Agathon, as you did, first describing who Eros himself is and what sort of character he has, and then going on to what he does.”1 Method: 1. categorize: Is Eros a god, a mortal or a daimon?2. characterize: Is Eros good? Bad? Beautiful?3. describe behavior: Is Eros helpful to men? Plato learned this method from Socrates who learned it from Diotima. “All of Western philosophy is but a footnote to Plato…”-- Alfred North Whitehead 1. Plato, Symposium, edited by C.J. Rowe, Aris & Phillips Classical Texts, 1998, p.77

3. How to write a definition (1) • If a good one exists refer to it. See dictionaries and ISO standards. Or try google define:

4. How to write a definition (2) • Otherwise choose a suitable method: • Intensional • Extensional • Ostensive • Ad-hoc • Theoretical • Operational • Genus (super class) and difference, the classic method • Key: Determine the intension of the concept and include examples of how the term is used.

5. Intension and Extension • The intension of a concept is its set of distinguishing characteristics • It is essentially a formula for testing if something is an instance of the concept. • The extension of a concept, on the other hand, is determined by its intension, and is the set of all those classes and objects that each have the distinguishing characteristics of the concept.

6. Intension, Extension of Cardinal Subject field:Roman Catholic Church INTENSION: is a high church-official; ranks just below the pope; and is appointed by the pope to membership in the College of Cardinals EXTENSION: all the members of the College of Cardinals

7. Question 2.1: What is the super-class of Cardinal? What is the super-class of Cardinal? • Choose one answer: • College of Cardinals • pope • high church-official INTENSION: is a high church-official; ranks just below the pope; and is appointed by the pope to membership in the College of Cardinals

8. Answer 2.1: High Church-official - 3 Subject field:Roman Catholic Church INTENSION: is a high church-official; ranks just below the pope; and is appointed by the pope to membership in the College of Cardinals

9. Exercise 2.1 • 1. Pick out the intension of Purchase Order from the definition given below: • Purchase order (subject field: SAP MM-PUR) • A request or instruction from a purchasing organization to a vendor (external supplier) or a plant to deliver a quantity of material or to perform services at a certain point in time. • 2. What is the super-class (genus) of purchase order?

10. Answer to exercise 2.1 and new question 2.2 • Distinguishing characteristics: • A purchase order is a request or instruction • It is given by a purchasing organization • It is given to a vendor (external supplier) or a plant • It specifies either the delivery of a quantity of material at a certain point in time or the performance of services at a certain point in time • Super-class: • Request or instruction • How would you draw a subtype graph relating purchase order to its super-class?

11. Request Instruction Request or Instruction Purchase Order Purchase Order Answer to exercise 2.2 • Super-class: • Request or instruction

12. How to write a definition, extensional • If a good one exists refer to it. See dictionaries and ISO standards. • Otherwise choose a suitable method: • Intensional • Extensional • Ostensive • Ad-hoc • Theoretical • Operational • Genus (super class) and difference, the classic method A vertebrate is a mammal, reptile, amphibian, fish or bird.

13. screw: this screw: this kind of device How to write a definition: ostensive screw – In shipbuilding: “A revolving device that drives a ship throughthe water, consisting of two or more blades”

14. How to write a definition: what was covered so far • If a good one exists refer to it. See dictionaries and ISO standards. • Otherwise choose a suitable method: • Intensional • Extensional • Ostensive • Ad-hoc • Theoretical • Operational • Genus (super class) and difference, the classic method

15. Multiple Viewpoints of the Concept VEHICLE VEHICLE D1 – By medium of transportation WATER VEHICLE LAND VEHICLE AIR VEHICLE VEHICLE D2 – By method of propulsion NON MOTORIZEDVEHICLE MOTORIZED VEHICLE VEHICLE D3 – By principal type of load carried CARGO VEHICLE PASSENGER VEHICLE PASSENGER AND CARGO VEHICLE

16. Question 2.3: multidimensional view of the concept VEHICLE VEHICLE D3 D1 CARGO VEHICLE WATER VEHICLE D2 LAND VEHICLE PASSENGER AND CARGO VEHICLE NON MOTORIZEDVEHICLE MOTORIZED VEHICLE AIR VEHICLE PASSENGER VEHICLE AIRPLANE CAR DIMENSIONS: D1 – By medium of transportation D2 – By method of propulsion D3 – By principal type of load carried Give a definition of car based on this diagram.

17. Answer 2.3 VEHICLE D3 D1 CARGO VEHICLE WATER VEHICLE D2 LAND VEHICLE PASSENGER AND CARGO VEHICLE NON MOTORIZEDVEHICLE MOTORIZED VEHICLE AIR VEHICLE PASSENGER VEHICLE AIRPLANE CAR DIMENSIONS: D1 – By medium of transportation D2 – By method of propulsion D3 – By principal type of load carried a car is a motorized vehicle for transporting passengers by land