Description
Make sure you read the lectures and watch the below videos. Use the lecture and videos to write a deductive or inductive argument on climate change. Study all Seven Forms of deductive arguments introduced in your Lecture as well as the inductive types. Try to make a clear and succinct argument rather than a lengthy essay.Watch these videos and read the articles below for food for thought. Some pros and some cons.
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Objectives for this Module:
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Understand the difference between deduction and
induction.
Plus, Validity and soundness; strength and
cogency;
Be able to critically examine arguments for the
said properties.
Be able to demonstrate this in discussions and
written exercises.
Definition: A deductive argument is one where the conclusion
follows necessarily from the premises; and, an inductive
argument is one where the conclusion follows with degrees
of probability from the premises.
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Deductive Arguments: Below is a chart. It shows that
every argument is either Deductive, Inductive or
Fallacious. Deductive arguments have conclusions that
follow necessarily based on the form of reasoning.
Inductive argument have conclusions that follow from
probability and are based on content.
It It is useful to know Deductive common types of
arguments so we can spot them easily: Categorical
Syllogism; Arguments from Math; Arguments by
Definition. You will now learn other forms.
Let’s focus on Deduction first: Study the chart below. The
chart shows that only Deductive arguments can be valid. They
can be invalid, in which case they are either fallacious or fall
outside the class of deductive and are inductive.
Here is the Chart: Chart #1
Every argument is either:
1) Deductive
2) Inductive, or
3) Fallacious
Validity:
VALID >
Deductive
INVALID>
Inductive or
Fallacious
When is it Rational?
Rational> if it is deductive and valid; if it is inductive and
strong.
Irrational> if it is deductive and fallacious; if it is inductive and weak.
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DEFINITION OF VALIDITY: A valid deductive argument is one
where assuming the premises to be true (that is, IF the
premises are true), then the conclusion cannot be false. This is
not the same as saying that it is an argument that has true
premises and true conclusion is valid. The reason is you can
have an argument with true premise and true conclusion that
is invalid on account of bad reasoning. The only condition of
truth and falsity you CANNOT have for validity to obtain is
TRUE premises and FALSE conclusion.
What these charts show you is that you can have a variety of
values for validity except one: that is when the premises are
true and conclusion is false. Then the argument must be
INVALID.
If you have true premises and true conclusion and valid
reasoning, then it is also SOUND. If you have correct
reasoning and false premises and true conclusion or false
premises and false conclusion, you can still be valid but then
you are UNSOUND. From this you should have gathered that
validity is about HOW you reason, whereas soundness is
about the TRUTH and FALSITY of the premises and
conclusion.
Chart #3, from Thinking Well, by S. Kelly.There are seven
valid forms to learn up front. They appear here and below
and are in “Files”. We will practice with some argument
forms that are valid and invalid VALID and INVALID
Below are the definitions of the seven valid forms: Each of
these patterns is deductive and therefore, valid. We will
discuss them and then practice with ordinary language
exercises to identify the forms.
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Modus Ponens means you are affirming the
statement in order to conclude: If A then B, A,
therefore B.
Modus Tollens means you are denying to deny: If A
then B, not B, therefore not A.
Disjunctive Syllogism (argument) means you are
denying the first term to conclude the second term.
Hypothetical Syllogism means if you have A
implying B, and you have B implying C, then A can
imply C.
The basic pattern for Universal Syllogism is the
same as H.S. above, except it is made up of
Categorical Statements (statements containing All,
No, or Some).
Chain Arguments have this form but insert the
premise A, so allows for a conclusion of C.
Predicate Instantiation is a categorical form but it is
quite similar to Modus Ponens. It means the second
premise term shares the predicate because it belongs
to the class.
To help you conceive of what was just explained above,
please read the presentation on “Argument
Strength”. Chart #4: Here is the
link: ArgumentStrengthChart083.pdf
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Now, I would like you know some INVALID forms that
look similar to those above. If you study these you will
notice the similarities in pattern, but these are not
valid forms. You can find these in “Files” again and
find the sheet on INVALID ARGUMENT FORMS. It
appears below:
Chart #5, See below:
InvalidArgumentForms.doc
2) TESTING ARGUMENTS for Validity: We can test
arguments by way of these principles. We can look for a
form (valid or not), and additionally we can do an
INDIRECT TEST. Below you will see how to test Indirectly:
HOW TO TEST ARGUMENTS BY THE INDIRECT TEST
1) Assume true premises.
2) Assume false conclusion.
(Think! Could I have a case of an invalid argument where, if I
assume premises true my conclusion could be false?)
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Read the argument.
If it conforms to true premises and false conclusion,
then it is INVALID. If assuming true premises and
your conclusion CANNOT BE FALSE, then it is
VALID.
When VALID: We will say there is a
CONTRADICTION TO OUR TEST ASSUMPTION,
namely, #1 and 2 above do not occur.
When INVALID: We will say there is NO
CONTRADICTION TO OUR TEST ASSUMPTION,
namely, #1, and 2 occurs.
INDUCTION:
Important: For Inductive Arguments the same relationships
obtain as in the Hurley Chart above. The only difference is you are
testing content based on probability instead of form. The language
used, therefore, will be “Strong” (for Valid) and “Cogent” (for
Sound) as per our text.
Chart #6, Inductive Arguments Chart.
**INDUCTIVE ARGUMENT TYPES: It is useful to know the
Inductive common types of arguments so we can spot them
easily: Prediction predicts and goes beyond the information in
the premises; Cause and Effect argues from cause to effect or
vice versa; Generalization generalizes to all from samples;
Authority brings in an authority to conclude; Analogy
compares properties of different entities to conclude. You can
read about these in chapters 4, 5, 8, 9.
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