This document discusses various philosophical concepts related to defining terms, including vagueness, ambiguity, intensional vs extensional definitions, and principles for creating good definitions. It notes that most words are either equivocal or analogical, and that definitions should specify the essential nature or "genus and specific difference" of the thing being defined while avoiding arguments or negative/circular constructions. Precise use of language is important to avoid confusion and enable clear communication.

1. Vagueness and Ambiguity
Univocal, Equivocal, and Analogical
Intensional and Extensional Definitions
Principles for Definitions
Objects and Essential Natures
Common Sense Logic
Chapter 1.4—1.6

2. Some objects are discrete; others exist on a
continuum.
Chairs vs. Clouds
Question: when is a word vague? Answer: when the
range of things on a continuum to which it refers is
not precisely defined.
Huh? That’s somewhat “vague”
What is Vagueness?

3. How precise must a definition be?
Old growth forests vs. New growth forests
Reality consists of discrete objects and continuums
How do we distinguish between rich people and poor
people?
Possible implication: are all divisions, along a
continuum, arbitrary?
Reality is (Partially) Vague

4. Ambiguity=when there are two or more unrelated
kinds of things to which a word refers
For example, “Key” has several possible meanings
“Please count the number of keys in the room”
Some words can be both vague and ambiguous
For example, “Bank” is vague because, when referring to
the sides of a river, it’s not obvious where it begins and
ends; it can be ambiguous because it can refer to several
objects
What is Ambiguity?

5. Equivocation
All factories are plants
All plants are made of organic material
Therefore, all factories are made out of organic material
Analogy
“Spinach is a healthy food; Fred’s complexion is looking
healthy”
“Bad” and “Good” Ambiguity

6. There are few words that are completely unambiguous
(i.e. univocal)
Most words are either equivocal or analogical
Analogical words help us better understand reality
Newton: the solar system is like a giant clock
Is it contradictory to say of two things that they are both
different and not different?
Maybe yes, maybe no
The Necessity of Analogy

7. Intension=all the characteristics, traits, and properties
of the word which makes it what it is
For example, “television”
An electronic instrument capable of receiving
electromagnetic radiation and turning it into pictures and
sounds
The intension is the concept
What is Intension?

8. Extension=all the things to which the word refers
For example, “television”
All past, present, and future television sets
The extension is the thing
What is Extension?

9. The intension of a word increases as the list of
characteristics included in the meaning of the word
increases
For example, “Irish Setter” is more specific than “dog,”
and “dog” is more specific than “animal”
As the intension of a word increases, the extension
typically decreases
The number of things referred to by “Irish Setter” is
fewer than is referred to by “dog”
A Principle for Intension

10. However, sometimes increasing the intension has no effect
on the extension
“Female President of the United States” vs. “Republican
Female President of the United States”
The second has a greater intension; yet the extension is
identical, since there is neither a female President of the
United States, nor a Republican female President of the United
States
Note: this is philosophically significant. The meaning of
words can never be reduced to their reference (i.e.
extension)
An Exception to the Rule

11. 1) Genus and specific difference
Genus=the next larger or more general category to which a
term belongs (e.g. Irish Setter, dog, animal, living thing)
Specific difference=that which distinguishes the word being
defined from other members of the genus (e.g. having
long, reddish hair, slender bodies, big chest, and long ears are
differences that distinguish Irish Setters from other dogs)
Species=the word being defined (e.g. Irish Setter)
Intensional Definitions

12. 2) Operational
Provides a test or procedure for determining what
something is
For example, cookbooks often define “done” like this: “A cake
is done if a toothpick placed into the middle comes out without
dough sticking”
Intensional Definitions

13. 3) Precising
Sets quantifiable limits to the range on a continuum to
which a word is to be applied
The lines being drawn are somewhat arbitrary, but must
still be reasonable
For example, we know when someone is intoxicated, but it’s
difficult to identify the line of demarcation
Intensional Definitions

14. 4) Stipulative
A specific meaning is assigned to a word in order to make a
distinction or clarify a discussion
Words must be “public” in order to be useful for
communication
Sometimes semi-private words are allowed (e.g. “fish”)
Necessary to avoid wholly verbal disputes
For example, the use of the word “freedom” in political
debates
Intensional Definitions

15. Three ways of specifying the extension of a word
1) Demonstrative definitions
For example, pointing to a television set in the room, to define
“television”
2) Enumerative definitions
For example, “baseball player” defined as Babe Ruth, Joe
Dimaggio, Mickey Mantle, etc.
3) Definition by subclass
For example, defining “insects” by listing ants, spiders, and
flies.
Extensional Definitions

16. 1) Avoid definitions that are too broad
“An automobile is a vehicle with wheels”
2) Avoid definitions that are too narrow
“An automobile is a vehicle designed to transport up to
four people with comfort and convenience”
Principles for Definitions

17. Why precise definitions matter
Because if there is confusion regarding what is being
discussed, miscommunication is inevitable
Some examples: 1) In what sense is Jesus Christ divine? 2)
What does it mean to know something? 3) What is
evolution?
An entire branch of contemporary philosophy (i.e. the
“analytic” tradition) is concerned with the precise use
of language and the meaning of terms.
For example, “the present King of France is bald”
Why Precision Matters

18. 3) If possible, avoid circular and negative definitions
Circular: “An A paper is a paper which the instructor says
deserves an A”; “God is a divine being”
Negative: “An organic substance is a substance which is
not organic”
4) Definitions shouldn’t be needlessly figurative/obscure
“Architecture is frozen music”; “A bunny is a mammalian of
the family Leporidae of the order Lagomorpha that are
furless and blind”
More Principles…

19. 5) Definitions shouldn’t be argumentative
“Democrats are pointy-headed liberals who always have
their hands in other people’s pockets”
“Abortion is the intentional murdering of an innocent
human person”
Most of us will agree that this is what abortion entails, but
it’s argumentative (and question begging) to include this
entailment in the definition.
Avoid Argumentative Definitions

20. Keep in mind the different purposes of definitions and
arguments
Arguments: to reveal what is true, good, or beautiful
Definitions: to serve as preliminaries to arguments by
specifying what something is
Once we know what something is, then we can
rationally discuss whether it’s true, good, or beautiful
The Role of Good Definitions

21. 6) Must specify the essential nature of the thing
being defined
Problem: do things even have an essential nature?
For example: 1) what is a human being? 2) what is morality?
3) what is beauty? 4) what is the soul?
Necessary and sufficient conditions
Heraclitus: “All is flux”
The Metaphysics of Definitions

22. We’ll be looking more closely at the metaphysics of
Aristotelian realism, emphasizing the distinction
between substances and attributes, the importance
of contingency and necessity, and the difference
between real and nominal definitions.
We’ll also highlight how a proper understanding of
these issues is essential for refuting positivism and
relativism.
Looking Forward to Next Week…