Argument and Explanation

Argument and Explanation 5.1 Two kinds of rationale: argument and explanation In section 3 we observed that there are two kinds of reason: evidence and cause. These two kinds of reason correspond to two kinds of rationale: argument and explanation. We define these concepts as follows: • • An argument is a rationale in which the reason presents evidence in support of a claim made in the conclusion. Its purpose is to provide a basis for believing the conclusion to be true. An explanation is a rationale in which the reason presents a cause of some fact represented by the conclusion. Its purpose is to help us understand how or why that fact occurs. The best way to remember the difference between argument and explanation is to think of them as answering two different questions. • • An argument answers the question: How do you know? This is a request for evidence. An explanation answers the question: Why is that so? This is a request for a cause. Here is a diagram representing these relationships. It is important to develop a solid grasp of the relationships represented above, and to learn to use the terms exactly as they have been defined. All of these words have meanings in ordinary language that are not precisely the same as the ones we give them here. For example, most people think of an argument as a kind of verbal dispute, but here it a particular kind of logical structure: it is a rationale in which evidence is given for the truth of some claim. Similarly, we often think of an explanation as just a description or account of the facts. Here, however, an explanation is another kind of logical structure: it is a rationale that provides a cause of some accepted fact. You will also get profoundly unsatisfactory results if you think of the difference between argument and explanation in vaguer terms than represented above. For example, it will not do to think of explanation as a kind of rationale that is "based on facts" or an argument as rationale that is "based on opinions". Phrases like these are just too vague distinguish these two kinds of rationale. 5.2 Knowledge and understanding It is sometimes said that the purpose of inquiry is to provide knowledge and understanding of the world. This is a useful expression to remember as it accurately reflects the distinction between argument and explanation. We create knowledge by providing evidence for our views; i.e., by constructing arguments. We create understanding by discovering the causal structure of the world; i.e., by constructing explanations. This expression also helps us to remember that argument and explanation make equally important contributions to rational inquiry. Many people- even many people who write logic books- are under the impression that reasoning is all about learning to make and evaluate arguments. But this formulation neglects the fact that we devote an equal amount of reasoning to understanding facts that have already been established. 5.3 Simple Examples In the next few sections we will be discussing ways of distinguishing argumentative from explanatory reasoning. This can actually be a pretty challenging task. This is partly because the majority of reasoning is perpetrated by ordinary folks who have never been taught the difference between argument and explanation. It's also partly because people sometimes argue and explain at the same time, again without really knowing what they are doing. In fact, given the potential for confusion, it is actually surprising how often we can determine whether the reasoning we are given is mainly argumentative or explanatory in nature. For now, let's just look at a simple example to make sure we have the distinction between argument and explanation dialed in. Consider this: • I think Hazel must have forgotten about our appointment. She's an hour late. This reasoning is most plausibly reconstructed as an argument. The speaker claims that Hazel has forgotten the appointment, and gives as evidence for this conclusion, that Hazel is an hour late. We reconstruct it as follows: (Note: Because we now know that the conclusion of a rationale is always written on the right and the reasons are always written on the left, we will no longer label them as such. However, under the conclusion we will now identify the rationale as either an argument or an explanation.) Now here is an example in which the same basic information is presented in a different way. • Hazel is an hour late for our appointment because she forgot about it. In this form, the reasoning is most plausibly reconstructed as an explanation. The speaker points out the fact that Hazel is an hour late for the appointment, and proposes a particular cause of that fact, namely that Hazel forgot about it. You'll recall that at the end of section 3 we noted that cause and evidence have a reciprocal relationship: smoke is evidence for fire because fire causes smoke. Although this relationship is not always apparent, it is in this case. In the argument, Hazel's tardiness is offered as evidence that she forgot the appointment. In the explanation, Hazel's having forgotten the appointment is presented as the cause of her tardiness. 5.4 Are there any keywords that help to construct rationales? There are no simple keywords or linguistic indicators that reliably distinguish argumentative from explanatory reasoning. Looking at the argument you might say that the phrases I think and must have suggest that the speaker is arguing. On the other hand, regarding the explanation, we might say that the use of the word because seems to indicate that a cause is being offered. Unfortunately these indicators can't be reliably generalized. Consider: • I think the fact that Hazel is an hour late must be because she forgot about our appointment. This example, like the argument above, contains the phrases I think and the word must, but it is still best construed as an explanation of the fact that Hazel is late. It is, however, useful to note that the word because is a very reliable indicator of the reason/conclusion relationship. Unlike the words so, hence, thus, and therefore, which indicate that a conclusion is about to be given, the word because indicates that a reason is about to be given. Whether it is an argument or an explanation, almost any sentence of the form A because B will be properly reconstructed so that A is the conclusion and B is the reason. 5.5 Extended arguments and explanations We noted in section 4 that rationales can be extended into branching and chaining patterns. This applies to arguments and explanations to an equal degree. It is very important to understand that arguments and explanations make distinct contributions to rational inquiry, and it is equally important not to conflate them. In the case of branching and chaining rationales, conflation can occur by including reasons that are functioning as evidence and reasons that are functioning as cause in the same rationale. Consider this example: • Martha: I think the battery on my iPod is worn out. It doesn't play as long as it used to. I guess it's just been recharged too many times. Now here is one possible reconstruction of this reasoning. The relation between R1 and the conclusion is clearly evidential in nature: the fact that Martha's iPod doesn't play as long as it used to is presented as evidence that the battery is worn out. However, R2 is not additional evidence that the battery is worn out. Rather, it is a proposed cause. Hence, what Martha has given us here is actually an argument combined with an explanation. We will see later that this is extremely common. The important thing to understand for now is that we never combine the two types of rationale. If we identify a rationale as an argument, then every reason in the rationale must be evidential in nature. Similarly, if we identify a a rationale as an explanation, then every reason in the rationale must be causal in nature. Hence, the proper reconstruction of this reasoning would actually be two distinct rationales as follows: You will notice that in this case the two distinct rationales have precisely the same conclusion, which can seem redundant or unnecessarily cumbersome. It is a bit cumbersome, but it is important to separate them nevertheless. To understand why it can help to think of the argument as as a function that inputs evidence and outputs factual knowledge. Hence, the output of the argument becomes the input of the explanation conclusion. Put differently, if an argument is supported with good evidence, then we are inclined to treat its conclusion as a fact. At that point, it becomes reasonable to ask for another kind of rationale, namely an explanation of that fact.