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Lecture 1

PHIL 180 Lecture Notes - Lecture 1: We Sing, Ad Hominem, Hypothetical Syllogism

37 pages80 viewsFall 2016

Department
Philosophy
Course Code
PHIL 180
Professor
James Tappenden
Lecture
1

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1.1 Arguments, Premises, and Conclusions
Logic: the organized body of knowledge, or science, that evaluates arguments
Aim of logic is to develop system of methods to use as criteria when judging
arguments
Argument: a group of statements, one or more of which (the premises) are claimed to
provide support for, or reasons to believe, one of the others (conclusion)
Two types of arguments:
Ones where premises support conclusion and ones where they do not
Former = good argument and latter = bad argument
Purpose of logic is thus to evaluate arguments by developing methods and techniques
that allow us to distinguish between good arguments from bad
What is an argument?
Group of statements
Statement is either true or false, typically a declarative sentencee
Truth and falsity are two truth values of a statement
Questions, proposals, suggestions, commands are not statements
Statements that make of argument divided into one or more premises and
one conclusion
Premises: statements that set forth the reason or evidence
Conclusion: statement that the evidence is claimed to support or imply
Important to be able to tell difference between conclusion and premises
Conclusion indicators: therefore, wherefore, thus, so, hence, etc
Premise indicators: since, because, for, in that, given that, etc
Arguments that lack indicators usually have conclusion as first sentence
When argument is restructured using logical principles, conclusion comes
last (P1, P2, P3, C)
Passages that contain arguments can have statements that are neither premise
or conclusion
Inference: the reasoning process expressed by an argument (used
interchangeably with word argument)
Proposition: the meaning or information content of a statement (used
interchangeably with word statement)
1.2 Recognizing Arguments
Not all passages contain arguments
a. In order for passage to contain an argument:
At least one of the statements must claim to present evidence or reasons
Must be a claim that the alleged evidence supports or implies something
Premises must claim to present evidence or reasons that support or imply something
Explicit claim: asserted by premise or conclusion indicator words (thus, since, because)
Implicit claim: inferential relationship between statements in a passage, but no indicator
words
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In deciding whether there is a claim that evidence supports or implies something:
a. Look for premise and conclusion indicator words
b. Look for presence of inferential relationship between statements
Insert word “therefore” before various statements to see whether it
makes sense to interpret one of them as following from the others
Simple Non Inferential Passages:
Lack a claim that anything is being proved (can contain premises, but lacks claim)
Warning: form of expression that is intended to put someone on guard against
dangerous situations
If no evidence is given that such statements are true, there is no argument
“Watch out that you don’t slip on the ice” “Bob is a blabbermouth”
Piece of Advice: form of expression that makes a recommendation about some future
decision or course of conduct
Statement of Belief (Opinion): an expression about what someone happens to believe
or think about something
Loosely Associated Statements: may be about same general subject, but lack a claim
that one of them is proved by the other
Report: a group of statements that convey information about some topic or event
Expository Passages:
Kind of discourse that begins with a topic sentence followed by one or more sentences
that develop the topic sentence
If purpose of passage is to also prove the topic sentence, it can be an argument
Ask yourself if topic sentence is something that everyone agrees with, if
not, it can also be an argument
Illustrations:
An expression involving one or more examples that is intended to show what something
means or how it is done
Many illustrations contain indicator words and are confused with arguments
Arguments from example: illustrations taken as arguments
To interpret illustrations as arguments or not, determine whether the passage shows
how something is done or whether it also purports to prove something
If claim is something everyone accepts, it is not an argument
Explanations:
An expression that purports to shed light on some event or phenomenon accepted as tru
Composed of two distinct components
Explanandum: the statement that describes the event or phenomenon to be
explained
“The sky appears to be blue from the earth’s surface”
Explanans: the statement or group of statements that purports to do the
explaining
“Light rays from the sun are scattered by particles in the atmosphere”
Often mistaken as arguments due to the fact the word “because” is used
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Explanations used to show why something is the case; arguments used to prove that
something is the case
Distinguish argument from explanation:
Identify statement that is explanandum or conclusion
If this statement is matter of fact then it is explanation
To determine if statement is an accepted matter of fact look at
intended audience (source of passage)
Conditional Statements:
An “if...then…” statement
Made up of two component statements:
Antecedent: component statement immediately following the “if”
Consequent: component statement immediately following the “then”
“Then” occasionally left out and order of two components can be switched
Not an argument because there is no assertion that antecedent or consequent is true
No single condition statement is an argument, however, a conditional statement may
server as either the premise or the conclusion (or both) of an argument
The inferential content of a conditional statement may be reexpressed to form argument
Antecedent expresses a sufficient condition, meaning the truth of the antecedent is
sufficient to guarantee the truth of the consequent
Consequent expresses a necessary condition
Factual Claim: claim that presents evidence or reasons
Inferential Claim: claim that the evidence or reasons imply something
Inferential Relationship: one claim that presents evidence and one claim that
implies something from that evidence
Sufficient Condition: A is sufficient condition for B whenever the occurrence of A is all
that is needed for the occurrence of B
Being a dog is sufficient condition for being an animal
Necessary Condition: B is necessary condition for A whenever A cannot occur without
B
Being an animal is a necessary condition for being a dog
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