This chapter covers three skills that you need to do philosophy well: reasoning (or argument), reading and writing. You may want to skim through at the least the first section on argument before beginning Chapter 2, but without actually doing some philosophy, this chapter may be a little too abstract to understand completely. So perhaps come back to it when you need to.
Philosophical argument
At the heart of philosophy is philosophical argument. Arguments are different from assertions. Assertions are simply stated; arguments always involve giving reasons. An argument is a reasoned inference from one set of claims â the premises â to another claim, the conclusion. The premises provide reasons to believe that the conclusion is true. If the premises are true, the conclusion is more likely to be true. Arguments seek to âpreserve truthâ â true premises will lead to a true conclusion. It is worth knowing a little bit more about arguments straightaway.
Deductive argument
Philosophers distinguish between two types of argument â deductive and inductive. Successful deductive arguments are valid â if the premises are true, then the conclusion must be true. In this case, we say that the conclusion is entailed by the premises. Here is a famous example:
- Premise 1: Socrates is a man.
- Premise 2: All men are mortal.
- Conclusion: Socrates is mortal.
A valid deductive argument with true premises is called sound. But a valid deductive argument doesnât have to have true premises. Here is an example:
- Premise 1: There are gnomes in my house.
- Premise 2: My house is in Oxford.
- Conclusion: Therefore, there are gnomes in Oxford.
If the premises are true, then the conclusion must be true â so the argument is valid. But the premises arenât both true.
Give an example of a) an invalid argument; b) a valid argument with false premises; and c) a sound argument.
There are two ways that a deductive argument can âgo wrongâ. First, it could be invalid: even if the premises are true, it is possible that the conclusion might be false. Second, it could be unsound: even though the conclusion is entailed by the premises, at least one of the premises is false.
Inductive argument
A successful inductive argument is an argument whose conclusion is supported by its premises. If the premises are true, the conclusion is likely to be true, but it is still possible that the conclusion is false. So inductive arguments are not described as âvalidâ or âsoundâ.
Explain and illustrate the difference between inductive and deductive arguments.
But they can also go wrong in just two ways. First, the premises might not make the conclusion more likely â they donât offer good reasons for believing the conclusion is true. Second, one of the premises may be false.
One type of induction is induction through enumeration, as in this famous example:
- Premise 1: This swan is white.
- Premise 2: This other swan is white.
- Premise 3: That third swan is white.
- âŚ
- Premise 500: That swan is white as well.
- Conclusion: All swans are white.
The example shows that an inductive argument can be a good argument, but the conclusion can still be false!
Hypothetical reasoning
There are other types of inductive argument, e.g. hypothetical reasoning. In hypothetical reasoning, we try to work out the best hypothesis that would explain or account for some experience or fact.
A hypothesis is a proposal that needs to be confirmed or rejected by reasoning or experience.
Medical diagnosis provides an example â what would explain exactly this set of symptoms? This isnât a matter of comparing this case with other cases which all have exactly the same symptoms. There may only be some overlap or the case might involve some complication, such as more than one disease being involved. We use hypothetical reasoning â if such-and-such were true (e.g. the patient has disease x), would that explain the evidence we have? The evidence supplies the premises of the argument, and the conclusion is that some hypothesis is true because it accounts for the evidence.
When we are using hypothetical reasoning, it is not usually enough to find some hypothesis that can explain the evidence. We want to find the best hypothesis. What makes a hypothesis a good hypothesis? Philosophers have argued for several criteria.
- Simplicity: the best-known is probably Ockhamâs razor, which says âDonât multiply entities beyond necessityâ. Donât put forward a hypothesis that says many different things exist when a simpler explanation will do as well. A simpler explanation is a better explanation, as long as it is just as successful. For example, the explanation that plants flower in the spring in response to an increase in light and temperature is a better explanation than saying that they flower in the spring because thatâs when the fairies wake them up. The second explanation is committed to the existence of fairies â and we shouldnât think that fairies exist unless there is something we cannot explain without thinking they exist.
- Accuracy: a good hypothesis fits the evidence that we are trying to explain.
- Plausibility: a good hypothesis fits with what else we already know.
- Scope: a good hypothesis explains a wide range of evidence.
- Coherence: a good hypothesis draws and explains connections between different parts of the evidence.
The best hypothesis will be the hypothesis that demonstrates all these virtues to a higher degree than alternative hypotheses. A lot of philosophy involves arguing about which theory provides the best hypothesis to account for our experience.
What makes a good hypothesis?
Understanding arguments
Understanding arguments is central to doing philosophy well. That is why throughout this book, you will be asked to outline and explain arguments. Youâll be asked to do so in the exam, in 5- and 9-mark questions.
See UNDERSTANDING THE QUESTION, p. 272.
Understanding an argument involves identifying the conclusion, identifying the premises, and understanding how the premises are supposed to provide reasons for believing the conclusion. Use linguistic clues, like âsinceâ, âbecauseâ, âif ⌠then âŚâ and many others, to help you do this. It is also important to distinguish between what someone supposes for the purposes of argument, and what they actually want to assert.
Many arguments involve quite a complex structure, with some premises establishing an initial conclusion, which is then used as a premise to establish a second conclusion. In coming to understand an argument, it can be very helpful to create an argument map. This is a visual diagram of how the argument works. For example,
Figure 1.1 An argument map
Evaluating arguments
When you evaluate an argument, you are yourself making an argument. You are arguing that the argument evaluated is either a good or bad argument. In other words, the conclusion of your evaluation is that the argument evaluated is a good/bad argument, and you have to provide reasons to support this claim. There are three types of reason you can give, three different ways of evaluating arguments:
- As already stated above, you can argue that one or more of the premises is false. If you are right, then the argument does not give you a reason to believe the conclusion, because it rests on a false premise.
- As also already stated above, you can argue that the conclusion does not follow from the premises. If you are evaluating a deductive argument, you are claiming that the argument is not valid. If you are evaluating an inductive argument, you are claiming that the premises do not provide a (good or strong) reason to believe the conclusion. For example, with inferring the best hypothesis, you could argue that the conclusion is not the best explanation for the premises, e.g. that it isnât plausible or simple, or at least that the argument doesnât show that it is, e.g. there may be other explanations that havenât been considered.
- You can also evaluate the formal features of an argument. Without worrying about whether it is true, you can ask whether it is clear, whether the premises are relevant to the conclusion, whether the support offered by the premises has been demonstrated, and so on. You may want to offer an improvement on the argument, e.g. rephrasing it to be clearer, supplying missing premises, identifying assumptions, and so on.
Evaluating claims
In addition to evaluating arguments, you can evaluate claims on their own. In evaluating a claim, you provide an argument for thinking that it is true or false.
For any claim C (e.g. âGod existsâ), there are four related ways of discussing it, as shown in this diagram:
| C is true: God exists | C is false: God does not exist |
| 1 Arguments for C being true | 2 Arguments for C being false |
| 3 Objections to arguments for C being false | 4 Objections to arguments for C being true |
When you are arguing for or against a claim, donât overstate your case. Your claim is only as strong as the reasons that you can provide for it.
In 15-mark questions, you are typically asked to evaluate a claim. You need to break this down into a series of arguments and their evaluation (discussed below in WRITING PHILOSOPHY, p. 17). After youâve explained the claim, for each section of the answer, you should consider an argument for or against the claim, objections to that argument, and possible responses. Youâll also need to indicate how strong you think the argument is, and weigh up the strengths of the arguments for the claim against the strengths of the arguments against. This isnât a matter of âcomparing strengths and weaknessesâ on the page, but identifying what you think the really important and critical arguments or objections are. This is, of course, something that you need to argue for!
See UNDERSTANDING THE QUESTION, p. 272.
An aside: why reason?
Why, you may wonder, should we place so much importance on reasoning in this way? Is it worth it? Here are four quick reasons in favour of reasoning:
- To discover the truth
- To uncover poor reasoning, e.g. fallacies (see below) and sophistry
- To recognise when, where, and how a dialogue ceases to be reasonable or instructive
- To probe both sides of a controversial issue in a sensitive and intelligent way.
Can I justify these claims? If I present an argument in favour of reasoning, then Iâm using...
