Chapter 12: Argument Analysis

 

Chapter 12: Argument Analysis

1.      What is a Good Argument?

•   In our daily lives, we’re constantly hearing or making persuasive arguments. We may be listening to a colleague’s argument for why we should support one of her initiatives. We may hear an argument for why we should buy a certain product. Or we may need to make our own argument to get approval for one of our projects.

•   A good argument is an argument that is either valid or strong, and with plausible premises that are true, do not beg the question, and are relevant to the conclusion.

•   Intuitively, a good argument is one in which the premises provide good reasons for the conclusion. This is of course quite vague. Let us try to make it more precise. 

a)      Condition 1: The premises are true or highly plausible: This means that if we have an argument with one or more false premises, then it is not a good argument. The reason for this condition is that we want a good argument to be one that can convince us to accept the conclusion. Unless the premises of an argument are all true, we would have no reason to accept its conclusion.

b)      Condition 2: The argument is deductively valid or inductively strong: Deductively valid arguments are of course valuable. Valid arguments cannot lead us from true premises to false conclusions. But we have seen that inductively strong arguments play an equally important role in reasoning. Many good arguments are valid. Example:
All whales are mammals.
All mammals are warm-blooded.
So all whales are warm-blooded.

•   But it is not true that good arguments must be valid. We often accept arguments as good, even though they are not valid. Example:
No baby in the past has ever been able to understand quantum physics.
Kitty is going to have a baby soon.
So Kitty's baby is not going to be able to understand quantum physics.

•   This is surely a good argument, but it is not valid. It is true that no baby in the past has ever been able to understand quantum physics. But it does not follow logically that Kitty's baby will not be able to do so. 

•   To see that the argument is not valid, note that it is not logically impossible for Kitty's baby to have exceptional brain development so that the baby can talk and learn and understand quantum physics while still being a baby. Extremely unlikely to be sure, but not logically impossible, and this is enough to show that the argument is not valid. But because such possibilities are rather unlikely, we still think that the true premises strongly support the conclusion and so we still think that the argument is a good one.

•   In other words, a good argument need not be valid. But presumably, if it is not valid it must be inductively strong. If an argument is inductively weak, then it cannot be a good argument since the premises do not provide good reasons for accepting the conclusion.

c)      Condition 3: The premises are not question-begging: Notice that criteria #1 and #2 are not sufficient for a good argument. First of all, we certainly don't want to say that circular arguments are good arguments, even if they happen to be sound. Suppose someone offers the following argument:
It is going to rain tomorrow. Therefore, it is going to rain tomorrow.

•   So far we think that a good argument must (1) have true premises, and (2) be valid or inductively strong. Are these conditions sufficient? The answer is no. Consider this example:
Smoking is bad for your health.
Therefore smoking is bad for your health.

•   This argument is actually sound. The premise is true, and the argument is valid because the conclusion does follow from the premise! But as an argument surely it is a terrible argument. This is a circular argument where the conclusion also appears as a premise. It is of course not a good argument because it does not provide independent reasons for supporting the conclusion. So we say that it begs the question.

•   Here is another example of an argument that begs the question:
Since Mary would not lie to her best friend, and Mary told me that I am indeed her best friend, I must really be Mary's best friend. 

•   Whether this argument is circular depends on your definition of a "circular argument". Some people might not consider this a circular argument in that the conclusion does not appear explicitly as a premise. However, the argument still begs the question and so is not a good argument.

d)      Condition 4: The premises are all relevant to the conclusion: Consider this argument:
Albert Einstein was a physicist.
All physicists studied mathematics.
Albert Einstein played the violin.
Albert Einstein studied mathematics.

•   This is presumably a non-question-begging, sound argument. If we accept the premises, we ought to accept the conclusion. Yet there is something wrong with the argument—namely, that the third premise is irrelevant to the conclusion, even though it is true. If we remove this particular premise, it does not affect the strength of the argument at all. The extra premise is a distraction and is liable to create confusion, and it fails to provide a good reason for the conclusion. Bearing this in mind, we should require that a good argument does not contain any irrelevant premises. 

2.      Four Ways to Attack an Argument: There are four main ways to attack an argument: two direct methods and two indirect ones: 

1.      Direct Method 1: Attack the premises: If you can show that an argument relies on at least one implausible (questionable) premise, that is a good way of showing that the argument is not good enough. But sometimes you do not have to go all the way to show that a premise is false. You might argue that there is simply not enough evidence to show that the premise is true. This falls short of arguing that the premise is false, but it passes the burden of proof to the opponent. But remember, just because an argument has a false premise, it does not follow that the conclusion is false! 

2.      Direct Method 2: Attack the reasoning: Even if the premises are all very plausible, you need to check whether the reasoning of the argument is acceptable. The argument might be invalid or inductively weak, or question-begging. 

3.       Indirect Method 1: Attack the argument indirectly by attacking the conclusion: If you can show that the conclusion of an argument is false, this implies that there must be something wrong with the argument. This strategy of refuting (disproving) an argument is useful when it is difficult to evaluate an argument directly, perhaps because it is too long or convoluted (complicated). Of course, this strategy does not really explain what is wrong with the argument. 

4.      Indirect Method 2: Give an analogous argument that is obviously bad: The idea is to compare the original argument with another argument. If the new argument is obviously bad, and it has the same structure as the original one, then the original one is likely to be a bad argument as well. This is a good strategy to use when it is difficult to see what is wrong with an argument, or your opponent refuses to admit that the argument is no good. 

Consider the following example:

 

Capital punishment is wrong because it is always possible to punish an innocent person by mistake.
Attack the Premises:	Is it always possible that an innocent person is executed by mistake? It might be argued that in some crimes there were many independent witnesses. Perhaps the criminal was apprehended (arrested) right away at the crime scene, and the whole crime was recorded on surveillance video. There is therefore little doubt that the person being caught is guilty.
Attack the Reasoning:	Even if mistakes are always possible, this is just one consideration and it does not immediately follow that capital punishment is wrong. Maybe there are many other considerations in support of capital punishment. We need to balance these factors before deciding whether capital punishment is acceptable or not.
Attack the Conclusion:	Punishment should be proportional (of the right size) to the crime. Capital punishment is not wrong because this is what justice requires in the case of hideous (extremely ugly) crimes.
Give an Analogous Argument that is Obviously bad:	With imprisonment, it is also possible to punish an innocent person by mistake. But it would be absurd to stop sending people to jail because of this.

Of course, there is a lot more we can say about capital punishment. The responses just given might not be very convincing, and you need not agree with any of them. They serve only to illustrate the fact that many arguments can be attacked in more than one way. 

3.      Argument Analysis: Checklist: The analysis of an argument is one of the most basic parts of critical thinking. To sum up, there are three main steps: 

a)      Clarify the argument.

b)      Evaluate the argument.

c)      Think about further relevant issues. 

Step	Tasks and Questions
1. Clarify the Argument	Identify premises and conclusion. Clarify the keywords. Simplify the argument using your own words.  Draw an argument map.
2. Evaluate the Argument	Is the argument a good one? Are the premises plausible? Is the argument valid or inductively strong?  Any fallacy in the argument?  Any reason to think that the conclusion is false?  Any obvious counterexample?
3. Explore Further Issues	How good is the argument overall? How important is the argument? Is the conclusion surprising? Can the argument be repaired or improved? Are there other arguments with similar conclusions?  What about arguments with the opposite conclusion?  Can the argument be applied elsewhere?  Any further information that might be relevant?

 

END OF THE PART