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Argument
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- 2. What is anargument?
- 4. Standard Form Arguments arelogical structures which present reasons (premises) that lead to a conclusion. Arguments come in all shapes and forms. Logicians use a form of the following kind: Premise 1 – All men are mortal Premise 2 – Socrates is a man _____________________________ Conclusion – Therefore, Socrates is mortal This is called standard form.
- 5. Not all argumentsare good arguments, so, having identified an argument, the next task is to evaluate it. If you are asked to “critically evaluate” a philosopher’s argument you are being asked to evaluate the whole structure NOT offer counter arguments against the conclusion (although some times you are also being asked to do this). Arguments can be described as “good” or “bad,” “weak” or “strong” according to a range of criteria. There are three fundamental terms that are used in evaluating arguments: Validity, Truth, and Soundness
- 6. Validity An argument isvalid if and only if it is not possible for all of the premises to be true and the conclusion false. The conclusion follows from its premises. The conclusion must be true if the premises are true. VALID All senators are paid Sam is a senator --------------------------- Sam is paid INVALID All senators are paid Sam is a paid --------------------------- Sam is a senator
- 8. Truth Although a deductiveargument must be valid to be a good argument, validity is not enough. One reason is that an argument can be valid even when all of the statements that it contains are false. All clowns are from London Dr Scott is a clown ----------------------------------- Dr Scott is from London This is a “bad” argument. Both of its premises are false (debatable!...still). Nonetheless, this argument IS valid.
- 9. Soundness When an argumentis both valid and all its premises are true, then it said to be sound. If it fails to meet either one, it is unsound. A sound argument must have a true conclusion.
- 10. Monty Python’s ArgumentClinic “She’s a witch!”
- 11. Inductive Reasoning Inductive reasoningis strong because: It relies on experience that may be universal, or at least testable It is flexible – there is more than one possible conclusion It does not demand that we accept definitions as fixed But it may be weak because: It relies on accepting the nature of the evidence It demands overwhelming good reasons for accepting that the conclusion is the most likely Alternative conclusions may be just as convincing
- 12. Deductive Reasoning Deductive reasoningis strong because: It does not depend on variable or misunderstood experience It accepts that words and definitions have fixed and agreed meaning There are no alternative conclusions But it may be weak because: It leads to apparently logically necessary conclusions It depends on whether one accepts that the premises are analytically true It can only say that if certain phenomena are the case, we might be able to make certain claims about them
- 13. Critically evaluating arguments 1st– Identify if it is based on inductive or a deductive reasoning. You can then say how this might make it weak or strong, respectively. 2nd – If it is deductive you can then assess whether it is valid or invalid. 3rd – If it is valid you can assess whether it is sound or unsound. 4th – If it is inductive you can assess whether it is cogent* or uncogent. * A “cogent” argument is “convincing or believable.” 5th – The next step is to look at fallacies, refutations, contradictions, counterarguments, etc.
- 16. Fallacies The Nizkor Project UsingDr. Michael C. Labossiere’s Macintosh tutorial Fallacy Tutorial Pro 3.0 See also Logical Fallacies and Logical Fallacies 2 iTunes Podcasts