Transcript Argumentation

Argumentation
A Primer in Logic
Declaration of Independence
The representatives of the
thirteen American colonies
wanted to justify to the world
their rebellion against England.
They used a rational argument
to support this thesis:
“These United Colonies are, and of right ought to be,
Free and Independent States…and that all political
connection between them and Great Britain is, and
ought to be, dissolved.”
The Basic Argument
Tyrannical rulers deserve no loyalty.
King George III is a tyrannical ruler over
the thirteen Colonies.
Therefore, King George does not deserve
their loyalty.
Because the Colonies are not obliged to be
loyal to George II, they are free to declare
their independence.
Deductive Argument
Clearly stated premises.
Conclusion is necessary. If the premises
are true, then you have to accept the
conclusion. “Ironclad logic”
If the argument is valid then you can
disagree only by denying one of the
premises.
Declaration of Independence
First premise
Tyrannical rulers deserve no loyalty.
How do we know that this is true?
Declaration of Independence
First Premise – Tyrannical rulers deserve no
loyalty.
Self-evidence, truths that any thinking
person can easily recognize: We hold these
truths to be self-evident…”
Authority, using ideas from the wellrespected English philosopher John Locke:
“unalienable rights [of] life, liberty, and
the pursuit of happiness. That to secure
these rights, governments are instituted…”
Declaration of Independence
First Premise – True
Tyrannical rulers deserve no loyalty.
Declaration of Independence
Second premise
King George III is a tyrannical ruler.
How do we know that this is true?
Inductive Argument
No necessary conclusions. A reasonable
person can agree with the premises and
still disagree with the conclusions.
Inductive arguments are at best “probably”
true.
Most important arguments are inductive.
Inductive Argument — I
Analogy: One thing is like the other.
The weakest kind of inductive
argument
Plato’s Republic: Virtue in the human
soul is like justice in the state.
Inductive Argument — II
Generalization: What is true of one
thing is true of all. The basis for most
scientific laws.
Every crow I have ever seen is black,
so all crows are black.
Inductive Argument — III
Convergence: All the evidence points
in the same direction. This is the
prosecutor’s kind of argument.
The Declaration of Independence
uses a convergence argument.
Declaration of Independence
2nd Premise
A tyrant will:
 Not allow subjects to
make their own laws.
 Make sure his own people
are judges.
 Harass the people with
bureaucratic procedures.
 Deny civil rights of the
people.
 Use his military to
intimidate them . Etc. etc.
King George III has
 Prevented colonies from
passing their own laws
 Set up his own
judiciaries.
 Erected a multitude of
new offices
 Obstructed colonists in
exercise of their rights.
 Used military to keep
Colonies in line.
Declaration of Independence
Second Premise – True or False?
The colonists have a good case, but does the King
have good reasons that they are not taking into
account?
With inductive arguments there is no certainty,
only probability or likelihood.
The 2nd premise is probably true.
The Argument Restated
Tyrannical Rulers deserve no loyalty.
Proved by appeal to self-evidence and the ideas of a wellrespected expert.
King George III is a tyrannical ruler over
the American Colonies.
Proved by listing many ‘qualifications’ of a tyrant and
showing that George III meets them.
Therefore, King George III deserves no
loyalty from the American Colonies.