So, let’s assume that the ADB (and perhaps also the author) intended to argue something like this:
Urban villagers live in poor-quality housing with inadequate provision for basic services.
Therefore, we need new approaches to address the challenge of rising urban dwellers in the Pacific.
Unfortunately, this argument is hardly valid. One reason is that its premise does not mention current approaches to urban management. What if current approaches work fine, and we just need to give them a little time to succeed? In that case, the premise would be true, but the conclusion would be false, because we would not need new approaches.
To avoid this problem, we need to add something about what is wrong with current approaches. Recall that the quotation from Jauncey in the third sentence did specify something wrong with current approaches, namely, that they often do not include urban villages. So it might help to combine these arguments, but how? One possibility is that the premise in the first sentence provides a reason for the premise in the third sentence. This relation is not obvious, because these claims are never juxtaposed, and no argument marker indicates their relation. Nonetheless, the suggestion does make sense of the argument and supports this interpretation:
Urban villagers live in poor-quality housing with inadequate provision for basic services.
Therefore, we need to include all urban villages in urban management.
Urban villages are often not included in urban management.
Therefore, we need to change urban management so as to include urban villages.
This double argument – with two instances of the argument marker “therefore” – uses the conclusion of the first part as a premise in the second part. The two parts form a line pointing to the final conclusion, so this kind of structure is often described as linear.
We are still not finished, because the first argument is not valid. It is possible that urban villagers live in poor-quality housing with inadequate services, but we still do not need to include all urban villages in urban management. This combination could happen if their housing and services could be improved without including them in urban management. It also could happen if including them in urban management would do no good to improve their housing and services. Thus, the argument will be invalid until we add some suppressed premise about a relation between urban management and the quality of housing and services. Here’s a possibility:
(1) Urban villagers live in poor-quality housing with inadequate provision for basic services.
(2) All areas with people who live in poor-quality housing with inadequate provision for basic services need to be included in urban management.
(3) Therefore, we need to include all urban villages in urban management.
(4) Urban villages are often not included in urban manage- ment.
(5) Therefore, we need to change urban management so as to include urban villages.
This argument is (close enough to being) valid and presents a plausible line of reasoning.
Now we have finally arrived at a fair reconstruction of Jauncey’s argument. Of course, to say that this is his argument is not to endorse it, much less to claim that its conclusion is true. The reconstruction reveals several premises that could be questioned. Critics could deny premise (1) and claim that housing and basic services really are adequate in urban villages. Maybe these urban villages are not as bad as Jauncey claims. Critics also might deny premise (4) and claim that urban management plans almost always already include urban villages. Maybe these programs are not as bad as Jauncey claims. Finally, critics could deny premise (2) and claim that we should exclude some poor areas from urban management, either because it would be too expensive to include them or because they will better off if they learn to fend for themselves. To respond to such critics, Jauncey would need to add more arguments, so the reconstruction hardly settles the issue in its present form. What it does instead is to clarify where critics can target their objections and where Jauncey needs arguments to back up his premises. In those ways, reconstruction helps us understand Jauncey and the issues that he raises. That is all that it can hope to do, but that is a lot more than we could accomplish without reconstructing his argument.
Explanation
By moving from the third sentence to the first, we skipped the second. Did we miss part of the argument? Or does the second sentence present a different argument? Or more than one argument? I will suggest that this short second sentence actually gives two new arguments of a new kind with a new conclusion. To see why, we need to reconstruct the arguments in this second sentence.
The second sentence says, “There has been a rapid rise of urban villages in recent years due to increased poverty and the negative impacts of climate change.” The reason marker “due to” signals that what follows are premises in an argument for what came before:
There has been increased poverty . . . .
There have been increased . . . negative impacts of climate change.
Thus, there has been a rapid rise of urban villages in recent years.
This argument needs to be spelled out in much more detail, but let’s start by asking what purpose this argument is supposed to serve.
Jauncey might again want to persuade his readers to believe his conclusion. However, it is hard to see how this argument would accomplish that goal. It is also hard to see why he would need to convince his readers of this conclusion, since most of them probably already know that the number of urban villages has risen rapidly in recent years. Observations make that clear. So, assuming that Jauncey knows what he is doing (and otherwise, why pay attention?), he must be seeking some other goal.
What would that be? Well, even if you know that urban villages have arisen, you still might wonder why they have arisen. Why are so many people moving so quickly into poor-quality housing with inadequate basic services? This question is what this argument seeks to answer. The answer is increased poverty and climate change. Because so many more people have become poor and have been displaced by climate change, they are willing to move into bad housing with bad services. They have no option. This explanation helps us understand why this trend is occurring by pointing to its cause. So this argument seems to be aimed at explanation instead of persuasion or justification.
If that is its purpose, what is the argument? As before, the argument has two premises, so we need to ask whether they work together in a joint structure or instead should be seen as independent explanations for the conclusion. If they are independent, then we really have two arguments:
There has been increased poverty . . . .
Thus, there has been a rapid rise of urban villages in recent years.
There have been increased . . . negative impacts of climate change.
Thus, there has been a rapid rise of urban villages in recent years.
When we split the argument in the third sentence above, we saw that the two premises worked jointly, because each separate argument assumed a suppressed premise close to the explicit premise in the other argument. That is not the case here. Each of these two arguments is invalid, so each does indeed assume a suppressed premise. However, neither assumes the premise in the other argument. To that extent, these arguments work independently: One explanation is poverty, and the other is climate change. This structure is sometimes described as branching.
Starting with the poverty argument, what suppressed premise is needed to make it valid? The story was already mentioned above: When people become poor, they have no option better than to move into bad housing with bad services, so they are willing to put up with life in urban villages. With a few additions, we can build this explanation into an argument like this:
Poverty has increased rapidly in recent years.
As poverty increases, there are more poor people who are willing to live in bad housing with bad services. (suppressed premise)
Therefore, there has been a rapid rise in recent years of poor people who are willing to live in bad housing with bad se
rvices.
As more people become willing to live in bad housing with bad services, urban villages increase in number and size. (suppressed premise)
Therefore, there has been a rapid rise of urban villages in recent years.
This reconstruction puts quite a few words into Jauncey’s mouth, but some additions like these are needed to make each part of this argument valid. They are also supposed to capture his story about how poverty explains the rise in urban villages.
The climate argument works similarly but needs to be clarified in one way. The premise refers to “negative impacts” of climate change without specifying which negative impacts matter. In particular, climate change is likely to kill many people. However, deaths cannot by themselves lead to urban villages, since people living in urban villages are alive, of course. What creates urban villages is displacement. When some people are killed by storms due to climate change, other people then leave the areas that were destroyed by the storms, perhaps in order to avoid being killed themselves or perhaps because their old housing was destroyed by the storms that killed others. These movements of people to avoid the effects of climate change are what Jauncey probably meant to cite as an explanation of urban villages. If so, this branch of the argument can be reconstructed like this:
Climate change has increased rapidly in recent years.
As climate change increases, many people are displaced. (suppressed premise)
Therefore, many people have been displaced rapidly in recent years.
As more people are displaced, urban villages increase in size and number. (suppressed premise)
Therefore, there has been a rapid rise of urban villages in recent years.
This argument is valid but would not be valid without the suppressed premises, and Jauncey would presumably accept those suppressed premises. Thus, this reconstruction is a fair representation of what he probably had in mind.
The conclusion of the climate argument is the same as in the poverty argument, so one could say that the two arguments work together to give a more complete explanation of the rate at which urban villages are rising. Urban villages increase even more rapidly when both poverty and climate change lead more people to move into urban villages. Nonetheless, each reason by itself could be seen as adequate to explain why the rise of urban villages has been rapid, even if together they explain why it has been so very rapid.
As before, to reconstruct Jauncey’s argument is not to endorse it. Even though we are trying to make it look as good as possible, our reconstruction actually specifies which premises critics could attack or question. Are poverty and climate change really increasing so fast? Do poverty and climate change really displace people and lower their expectations? Do these effects cause poor people to move into urban villages? Jauncey might or might not be able to answer such questions. If not, critics might reject his argument and his conclusion.
Reconstruction does not always lead to a good argument. Indeed, sometimes it is not possible to reconstruct an argument in any way that makes it look any good at all. Nonetheless, even in such cases, reconstructing an argument can still help us understand it. This method can also show us how to determine whether it is good as well as how good it is. In that way, reconstruction paves the path to evaluation, which is the topic of the next chapter.
9
HOW TO EVALUATE ARGUMENTS
AFTER WE IDENTIFY AN ARGUMENT along with its purpose and structure and fill it out with suppressed premises, we finally reach the time to evaluate it—that is, to ask whether it is any good. To call something good, as we saw, is to say that it meets the relevant standards. So, what are the relevant standards for arguments?
One standard is pragmatic. Just as we call an advertisement good when it increases sales, because that is its purpose, so we call an argument good when it serves its intended purpose. If an argument is presented to persuade some audience, then it is good in this pragmatic way to the extent that it succeeds in persuading that audience. However, the argument might persuade only by tricking its audience into believing something that they have no real reason to believe. The argument might give no reason at all or only a very bad reason. Then it persuades without justifying.
If we seek justification, understanding, and truth instead of only persuasion, then we hold arguments to a higher standard. We want arguments that provide good and adequate reasons or at least some real reason as opposed to a trick or misdirection. But then we need standards for determining when reasons are good in some epistemic sense that has to do with truth and justification instead of only belief or persuasion. That is the kind of standard and value that we discuss in this chapter.
The particular relation to truth and justification that an arguer claims can be revealed by the argument’s form. Some arguers want their premises to guarantee their conclusions whereas others are happy with some evidence well short of any guarantee. On this basis, it is common to distinguish deductive from inductive forms of arguments, so we will follow that tradition, although we will see that this distinction is problematic in some ways.
WAS SHERLOCK HOLMES A MASTER OF DEDUCTION?
Let’s start with a few simple examples. Imagine someone who argues like this:
(I) Noel is a Brazilian.
Therefore, Noel speaks Portuguese.
This argument is clearly not valid, because Noel could easily be a Brazilian who does not speak Portuguese. Maybe Noel is a baby who is too young to speak any language or a recent immigrant who has not yet learned Portuguese.
Despite these weaknesses, it is easy to add a single suppressed premise that makes this argument valid:
(II) All Brazilians speak Portuguese.
Noel is a Brazilian.
Therefore, Noel speaks Portuguese.
Now it is not possible for both premises to be true when the conclusion is false. If the conclusion is false because Noel does not speak Portuguese, then either Noel is not a Brazilian (in which case the second premise is false) or Noel is a Brazilian who does not speak Portuguese (in which case the first premise is false). This relation between its premises and conclusion makes argument (II) valid.
Great, so it is valid! Does that make argument (II) any better than argument (I)? No. Adding the suppressed premise that turned invalid (I) into valid (II) simply shifted any doubts from the relation between the premises and conclusion in (I) to the first premise in (II). This shift merely raises the question of whether we should accept that added premise.
What kind of evidence could support the premise that all Brazilians speak Portuguese? Maybe the speaker generalized from the Brazilians whom he knows. Then his argument might seem like this:
(III) All Brazilians whom I know speak Portuguese.
Noel is a Brazilian.
Therefore, Noel speaks Portuguese.
Unfortunately, now the argument is back to being invalid, because it is possible that I do not know Noel, who does not speak Portuguese even though he is a Brazilian.
Another possibility is that the arguer read on Wikipedia that Brazilians speak Portuguese, and he assumed this meant all Brazilians.
(IV) Wikipedia says that Brazilians speak Portuguese.
Therefore, all Brazilians speak Portuguese.
Noel is a Brazilian.
Therefore, Noel speaks Portuguese.
The last three lines are just like argument (II), so that second part is still valid. However, the inference from the first line to the second line is clearly not valid, because Wikipedia might be wrong or might have been referring only to Brazilians in general rather than to every single Brazilian, including babies and recent immigrants.
This sequence of arguments teaches an important lesson. Argument (II)—repeated in lines 2–4 of (IV)—is the only one that is valid. By squeezing the argument into this stilted form, the speaker suggests that he intends argument (II) to be valid. After all, it is obviously valid, and it took effort to formulate it to be valid, so the speaker must have wanted it to be valid and to appear valid.
In contrast, arguments (I), (III), and the first two lines of (IV) are all obviously invalid, so speakers would not formulate these arguments in this way if they intended these arguments to be valid. This contrast shows that some speakers intend their arguments to be valid, while others do not.
That intention is the difference between deductive and inductive arguments. An argument is deductive if its proponent intends it to be valid. An argument is inductive if its proponent does not intend it to be valid. Thus, argument (II) is deductive, but arguments (I) and (III) are inductive. Argument (IV) combines an inductive argument in its first two lines with a deductive argument in its lines 2–4.
It might seem odd to distinguish forms of arguments in terms of what their proponents intended. The reference to intention is needed, however, because of bad deductive arguments, like this:
(V) All Brazilians speak Portuguese.
All citizens of Portugal speak Portuguese.
Therefore, all Brazilians are citizens of Portugal.
If speakers were ever confused enough to give this invalid argument, then the fact that they put it in this form would suggest that they intended it to be valid. That intention explains why we would classify this argument as deductive, even though it is invalid and fallacious.
Think Again: How to Reason and Argue Page 13