HUM 115 Lesson Five

1
Value and Descriptive Assumptions

• Critical Thinking Lesson 5

2
Introduction

• What is an assumption?
• James Randi Assumptions video.
• An assumption is an unstated belief that supports
  the stated reasoning.

3
Introduction

• Every argument has at least one assumption.
• An assumption is an idea that is taken for
  granted.
• Assumptions are hiddenthey are unstated.

4
Introduction

• Why is it important we locate important
  assumptions within an argument?
• To accept an argument you must also accept any
  assumption(s) the author or speaker is making.
• Because every argument will look convincing at
  first.

5
Introduction

• Why will arguments appear convincing at first?
• Because arguments are designed to convince you
  that the conclusion is true.
• Arguments are designed to convince you that the
  reasoning is good (i.e. the reasons are valid and
  support the conclusion).
• The presenter wants you to accept his/her
  argument.

6
Introduction

• Critical thinkers need to learn to examine the
  conclusion and reasons carefully for any
  important assumptions.
• Assumptions are important invisible links in the
  reasoning structure.
• Until you understand these invisible links, you
  cannot understand the argument.

7
Identifying Assumptions

• Look for assumptions
• That are needed in order for the reasons to
  support the conclusion.
• Are necessary for a reason to be true.
• That affect the quality of the argument.
• Types of assumptions
• Value Assumptions.
• Descriptive Assumptions.

8
Value Assumptions

• Critical Thinking Lesson 5

9
Value Assumptions

• What is a value?

10
Value Assumptions

• Values are unstated ideas that people see as
  worthwhile.
• Values provide standards of conduct by which we
  measure the quality of human behavior.

11
Value Assumptions

• Value assumptions are implicit preferences for
  one value over another in a particular context.
• Value assumptions are prescriptive in nature.
• A value assumption is an unstated idea that
  things should be a certain way.

12
Value Assumptions

• Prescriptive Assumptions
• Ethical in nature.
• Heavily influenced by a persons values.
• Argument impacted by values.

13
Value Assumptions

• Value assumptions
• Is taken for granted about the relative
  desirability of certain competing values.
• Is made when the author/speaker assumes that one
  value trumps other values in a particular context.

14
Value Assumptions

• How do we identify value assumptions?
• Realize that most people hold to the same basic
  value system.
• Realize that people do not view the same values
  equally (in each context).
• Capital Punishment Mercy or Justice.
• Abortion Life or Choice.

15
Value Assumptions

• Example of a value assumption (pg. 58)
• We should not legalize recreational drugs.
  Illegal drugs cause too much street violence and
  other crimes
• What value assumptions are present in that
  paragraph?

16
Value Assumptions

• Example of a value assumption
• They who would give up an essential liberty for
  temporary security, deserve neither liberty or
  security (Benjamin Franklin)
• What value assumptions are present in that
  example?

17
Value Assumptions

• We attach different levels of intensity to
  specific values at different times and in
  different contexts (Value Assumptions).
• Assumptions will only be accepted by those who
  share the values.
• When people disagree on value assumptions
  conflict may be the result.
• Recognizing that people have different value
  assumptions gives us a better understanding of
  what we read/hear (mainly on hot button
  issues).

18
Group Work

• Divide into groups of 3.
• Each group member should take a moment and think
  of two social controversies in which their value
  assumptions differ.
• Discuss the reasons for those differences with
  your group members.

19
Locating Value Assumptionsin Consequences

• Review.
• What are assumptions?
• What are value Assumptions?
• Look for assumptions
• That are needed in order for the reasons to
  support the conclusion.
• Are necessary for a reason to be true.

20

• In a prescriptive argument
• Each position/answer will bring about different
  consequences.
• Each consequence will have different levels of
  desirability or undesirability.
• The desirability of a consequence will depend
  upon a persons value assumptions.
• The desirability of the conclusions will be
  determined by
• The probability of the possible consequences.
• How desirability those consequences are.

21
Locating Value Assumptionsin Consequences

• Take note
• Typical Value Assumptions and Sample
  Controversies (pg. 60).
• Clues for Identifying Value Assumptions (pg. 62).

22
Descriptive Assumptions

• Critical Thinking Lesson 5

23
Descriptive Assumptions

• Descriptive assumptions
• Assumptions made about how the world is (past,
  present, future).

24
Descriptive Assumptions

• Example
• The car will get you to your destination,
  whatever it may be. I have driven this model of
  car on multiple occasions

25
Descriptive Assumptions

• Example
• The car will get you to your destination,
  whatever it may be. I have driven this model of
  car on multiple occasions

26
Clues For Locating Assumptions

• Keep thinking about the gap between the
  conclusion and reasons.
• Look for ideas that support the reasons.
• Identify with the writer.
• Identify with the opposition.
• Recognize the possible existence of other ways of
  attaining the advantages referred to in the
  reasons.

27
Clues For Locating Assumptions

1. Avoid stating incompletely established reasons as
   assumptions (dont restate a reason as the
   assumption. Assumptions are unstated).
2. Avoid focusing on trivial assumptions.

28

• Practice Makes Perfect!!
• Passage 3 (page 71).
• Identify the Issue, argument, and any Value or
  Descriptive assumptions.
• Make sure you label each assumption as either
  value or descriptive and explain why.

29
Reading

• Read chapter 6 Are There Any Fallacies in the
  Reasoning?
• Index Cards
• Flash Cards.
• Fallacy Names (side A).
• Fallacy Definitions (side B).
• Study, Study, Study!!!