Chapter 2. Classification
Summary
· Classifying is about creating a set of file folders in your mind and then putting the referents in the proper file.
· Concepts are ideas that represent classes of things we have grouped together and that function as mental file folders.
· The referents are the things we put in these folders. They are the individual subjects seen.
· Concepts can have a relationship where one is broader (genus) and another is narrower (species).
· Another classification for concepts are that they are abstract and the referents are concrete.
· The two rules of classification:
1. A single principle or set of principles should be used consistently so that the categories (species) are mutually exclusive (each species must exclude all the members of every other species) and jointly exhaustive (the species taken together (jointly) must cover (exhaust) all the objects in the genus).
2. The principles used should be essential.
· Organizing Concepts: To organize concepts into a classification diagram:
1. Find the highest-level (most abstract) genus.
2. Identify concepts that are species of that genus; they should have the same degree of abstractness.
3. Identify the principle of division that applies to the concepts in step (2); put the principle in brackets.
4. For each concept in step (2), identify any other concepts that are its species, and identify the principle of division (the single principle by which the concept has been divided into species).
5. Repeat step (4) for as many levels as necessary.
· Classifying is about creating a set of file folders in your mind and then putting the referents in the proper file.
· Concepts are ideas that represent classes of things we have grouped together and that function as mental file folders.
· The referents are the things we put in these folders. They are the individual subjects seen.
· Concepts can have a relationship where one is broader (genus) and another is narrower (species).
· Another classification for concepts are that they are abstract and the referents are concrete.
· The two rules of classification:
1. A single principle or set of principles should be used consistently so that the categories (species) are mutually exclusive (each species must exclude all the members of every other species) and jointly exhaustive (the species taken together (jointly) must cover (exhaust) all the objects in the genus).
2. The principles used should be essential.
· Organizing Concepts: To organize concepts into a classification diagram:
1. Find the highest-level (most abstract) genus.
2. Identify concepts that are species of that genus; they should have the same degree of abstractness.
3. Identify the principle of division that applies to the concepts in step (2); put the principle in brackets.
4. For each concept in step (2), identify any other concepts that are its species, and identify the principle of division (the single principle by which the concept has been divided into species).
5. Repeat step (4) for as many levels as necessary.
Chapter 3. Definitions
Summary
· Definitions tell us what is in the mental file folders (concepts).
· The Main Functions of Definitions
1. State the criteria for membership in the class of referents (group of things that have the same essential attributes).
2. Indicate the relationship between a concept and other concepts (a concept is what we are trying to define).
3. Condense the knowledge we have about the referents of a concept.
· Rules for Definitions (A definition should:)
1. Include a genus and a differentia.
2. Not be too broad or too narrow.
3. State the essential attributes of the concept’s referents.
4. Not be circular.
5. Not use negative terms unnecessarily.
6. Not use vague, obscure, or metaphorical language.
· Constructing Definitions (To construct a definition for a concept C:)
1. Find the genus of the concept – the broader concept that includes C and other, related concepts from which one needs to distinguish C.
2. Choose a differentia that distinguishes C from other concepts in the same genus. If there is more than one distinguishing attribute, choose the most essential one.
3. Check to make sure that the resulting definition is not circular, unnecessarily negative, or unclear.
· Definitions tell us what is in the mental file folders (concepts).
· The Main Functions of Definitions
1. State the criteria for membership in the class of referents (group of things that have the same essential attributes).
2. Indicate the relationship between a concept and other concepts (a concept is what we are trying to define).
3. Condense the knowledge we have about the referents of a concept.
· Rules for Definitions (A definition should:)
1. Include a genus and a differentia.
2. Not be too broad or too narrow.
3. State the essential attributes of the concept’s referents.
4. Not be circular.
5. Not use negative terms unnecessarily.
6. Not use vague, obscure, or metaphorical language.
· Constructing Definitions (To construct a definition for a concept C:)
1. Find the genus of the concept – the broader concept that includes C and other, related concepts from which one needs to distinguish C.
2. Choose a differentia that distinguishes C from other concepts in the same genus. If there is more than one distinguishing attribute, choose the most essential one.
3. Check to make sure that the resulting definition is not circular, unnecessarily negative, or unclear.
Chapter 4. Propositions
Summary
· A proposition is something we can assert in the form of a statement. A proposition is also said in the form of a declarative sentence (they declare that something is a fact). It also needs to have a subject and a predicate.
· Words in Propositions (To determine whether two sentences assert the same proposition:)
1. Use techniques of classification and definition to identify the concepts the words express.
2. Ignore differences in connotation.
3. Find a literal interpretation of all metaphors.
· Propositions and Grammar
1. Two different grammatical structures can be equivalent, just as two words can be synonymous.
2. A single sentence can assert more than a single proposition.
3. A sentence does not always assert every proposition that is expresses.
· A proposition is something we can assert in the form of a statement. A proposition is also said in the form of a declarative sentence (they declare that something is a fact). It also needs to have a subject and a predicate.
· Words in Propositions (To determine whether two sentences assert the same proposition:)
1. Use techniques of classification and definition to identify the concepts the words express.
2. Ignore differences in connotation.
3. Find a literal interpretation of all metaphors.
· Propositions and Grammar
1. Two different grammatical structures can be equivalent, just as two words can be synonymous.
2. A single sentence can assert more than a single proposition.
3. A sentence does not always assert every proposition that is expresses.