Argument Intro
Law of the excluded middle.
This law states that every statement is either true or false.
(1) Communists support unilateral disarmament.
(2) Liberals support unilateral disarmament.
______________________________________
(3) Therefore, Liberals are Communists.
Most of us would agree that statements (1) and (2) are true but that statement (3) is false. But the argument seems to imply that if statements (1) and (2) are true then statement (3) must be true. Since this argument is puzzling, let us schematize it and then analyze its content. We shall adopt the following symbols:
"C" stands for Communists
"L" stands for Liberals
"V" stands for "supports unilateral nuclear disarmament."
In schematic form the argument now looks like this:
(1) C is V
(2) L is V
(3) L is C
In order to test the accountability of the above argument, we now construct another argument with the same schematic form.
(1) All camels are vegetarians
(2) Lambs are vegetarians
_______________________
(3) Therefore, lambs are camels.
In schematic form the argument is identical to the argument in the previous paragraph.
(1) C is V
(2) L is V
(3) L is C
Since most of us would agree that this argument is unacceptable and since this argument is identical in form to the previous argument, we must also find the previous argument unacceptable.
The statements that provide support, offer proof, or provide evidence are called "premises."
"Premises" and "conclusion" are relative. That is, the same statement may be both a premise in one argument and a conclusion to another argument.
The classic paradigm of an argument is:
Premise 1: All men are mortal.
Premise 2: Socrates is a man.
_______________________
Conclusion: Socrates is mortal
Table 1
Elements of Language
Letters
Spelling
Words
Grammar
Sentences
Premise Argument Conclusion
paragraphs*
*Only some paragraphs contain arguments.
WHEN IS AN ARGUMENT ACCEPTABLE?
If an argument is composed of premises and a conclusion, then one of the differences between an acceptable argument and an unacceptable argument must lie in the relationship between the premises and the conclusion.
An argument that allows us to arrive at a false conclusion from true premises. An example:
Premise 1: All Communists vote for unilateral nuclear disarmament.
Premise 2: All Liberals vote for unilateral nuclear disarmament.
____________________________________________________
Conclusion: All Liberals are Communists.
The premises are true but the conclusion is false.
Violation of the rule of undistributed middle. This terminology means nothing to the reader at the moment, but it does indicate that memorizing a few rules and being able to identify the patterns will enable him to spot immediately those arguments that are unacceptable for reasons of form, that is, because of the relationship between preises and conclusion.
When an argument is valid but at least one of its premises is false, the argument is said to be "unsound." When an argument is both formally valid and its premises are all true, then the argument is said to be "sound."
This law states that every statement is either true or false.
(1) Communists support unilateral disarmament.
(2) Liberals support unilateral disarmament.
______________________________________
(3) Therefore, Liberals are Communists.
Most of us would agree that statements (1) and (2) are true but that statement (3) is false. But the argument seems to imply that if statements (1) and (2) are true then statement (3) must be true. Since this argument is puzzling, let us schematize it and then analyze its content. We shall adopt the following symbols:
"C" stands for Communists
"L" stands for Liberals
"V" stands for "supports unilateral nuclear disarmament."
In schematic form the argument now looks like this:
(1) C is V
(2) L is V
(3) L is C
In order to test the accountability of the above argument, we now construct another argument with the same schematic form.
(1) All camels are vegetarians
(2) Lambs are vegetarians
_______________________
(3) Therefore, lambs are camels.
In schematic form the argument is identical to the argument in the previous paragraph.
(1) C is V
(2) L is V
(3) L is C
Since most of us would agree that this argument is unacceptable and since this argument is identical in form to the previous argument, we must also find the previous argument unacceptable.
The statements that provide support, offer proof, or provide evidence are called "premises."
"Premises" and "conclusion" are relative. That is, the same statement may be both a premise in one argument and a conclusion to another argument.
The classic paradigm of an argument is:
Premise 1: All men are mortal.
Premise 2: Socrates is a man.
_______________________
Conclusion: Socrates is mortal
Table 1
Elements of Language
Letters
Spelling
Words
Grammar
Sentences
Premise Argument Conclusion
paragraphs*
*Only some paragraphs contain arguments.
WHEN IS AN ARGUMENT ACCEPTABLE?
If an argument is composed of premises and a conclusion, then one of the differences between an acceptable argument and an unacceptable argument must lie in the relationship between the premises and the conclusion.
An argument that allows us to arrive at a false conclusion from true premises. An example:
Premise 1: All Communists vote for unilateral nuclear disarmament.
Premise 2: All Liberals vote for unilateral nuclear disarmament.
____________________________________________________
Conclusion: All Liberals are Communists.
The premises are true but the conclusion is false.
Violation of the rule of undistributed middle. This terminology means nothing to the reader at the moment, but it does indicate that memorizing a few rules and being able to identify the patterns will enable him to spot immediately those arguments that are unacceptable for reasons of form, that is, because of the relationship between preises and conclusion.
When an argument is valid but at least one of its premises is false, the argument is said to be "unsound." When an argument is both formally valid and its premises are all true, then the argument is said to be "sound."
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