T.R. Edward 1 What is an argument? An alternative definition Author: Terence Rajivan Edward, University of Manchester. Abstract. Philosophers and logicians talk of arguments for conclusions. In a recent paper, Jeffrey Goodman identifies a common way of thinking about what an argument is. I propose a definition that is quite different to this common way. I also make two objections to Goodman's proposed definition. What is an argument? The word "argument" is used in at least two senses in English, but below I shall only be concerned with one of these senses. In the sense which I shall not be concerned with, we describe two people as having an argument if they openly disagree, each is trying to persuade the other and the interaction is emotionally intense. The word is used in another sense if someone asks, "What is the argument for thinking that human beings will colonize Mars this century?" or "Is there a good argument for going to war with North Korea?" In this sense, a good argument justifies its conclusion whereas a bad argument does not. Jeffrey Goodman calls this the logical sense of the word "argument." (2018: 591) In a recent and useful paper, he discusses some attempts to define an argument in this sense of the word. He tells us that an argument in the logical sense is commonly 1 regarded as a set of propositions, where each of the premises is a member of this set and so is the conclusion (2018: 590-591). Another philosopher also says that this is a common way of thinking (Walton 1990: 400). But not just any set of propositions is an argument. For example, the proposition that Mars is a planet and the proposition that I had porridge for breakfast are together a set of propositions 1 Goodman is not saying that this way of thinking is common among people in general. He finds that a number of textbooks conceive arguments in this way (2018: 5). He seems to be saying that this way of thinking is common among people who make statements about what an argument is. T.R. Edward 2 but not an argument. For those who accept the common way of thinking and aim to produce a definition, one of the tasks is to say what distinguishes an argument from just any set of propositions (2018: 592). A proposal Goodman discusses is that an argument consists of a set of propositions where one member of this set is (objectively) justified by the other members. Goodman rejects this definition because it does not allow for bad arguments to count as arguments (2018: 594). Bad arguments are arguments as well! There is a way of avoiding this problem which involves breaking with the common way of thinking. Goodman does not show awareness of it. Before presenting this way, first let us note that a proposition can be about another proposition. For example, let us call the following proposition A: Paris is the capital of France. And let us call the following proposition B: proposition A refers to France. Proposition B is about proposition A. We are now in a position to introduce my proposal. This is the proposal as it initially occurred to me. Something is an argument if and only if it is a proposition of the form "Proposition C is justified by propositions P1, P2, P3... Pn." (In this definition, "C" stands for conclusion, rather than being the next letter available given the earlier example!) This definition allows for bad arguments. A bad argument is a false proposition with the form identified above. There is a qualification I wish to add to the definition. I also want to count something as an argument if it is a proposition of the form "Proposition C is justified by propositions P1, P2, P3... Pn, in the following way..." What comes next is a specification of how the premises justify the conclusion, such as the inference rules involved. How does this definition break with the common way of thinking that Goodman identifies? The common way of thinking conceives of an argument as a set of propositions, T.R. Edward 3 where each of the premises is a member of this set, as is the conclusion. On the common way of thinking, an argument will always or almost always be a set which has more than one member, because most arguments have at least one premise which differs from the conclusion. But on my initial proposal, an argument is simply a single proposition, with a certain form. In short, an argument is a proposition that represents a justificatory relationship between propositions. (As far as I can see, the qualification above still allows us to think of an argument as a single proposition.) The initial proposal attracts me because of its simplicity, and the qualification does not seem to sacrifice this virtue. But the proposal, before and after qualification, requires that we paraphrase some of the things we say about arguments. For example, the claim that a certain argument has two premises and a conclusion will have to be understood as saying that the proposition which is this argument represents a certain conclusion as justified by two premises. At present I cannot see that such paraphrases are a problem. But I should say that the simplicity of the proposal, while attracting me, also makes me suspect that it does not perfectly capture ordinary usage. An ordinary use of a word is often very hard to capture exactly. Goodman's proposal Goodman makes a very different proposal for what an argument is, which is rooted in the common way of thinking. He writes: Take any graspable set of propositions. Any such set will have the following property: being entertainable by an agent (or group of agents) who further believes there is a relation of support among all the members of the set, save one, and that other member. Sets of propositions may never be entertained by anyone T.R. Edward 4 who believes there to be such a support relation among their members, but if and only if they have been so entertained at some time or other, they are arguments. (2018: 596) As I understand Goodman, what he is saying here is this. Take a set of propositions. Now separate off one of the propositions from the rest. Someone might believe that the other propositions justify this one proposition. If there is someone who believes this, or ever was someone who believed this, then the set of propositions is an argument; otherwise it is not. I shall make two objections to this proposal. The first objection is that it does not allow for circular arguments. One kind of bad argument is a circular argument, where the conclusion is also one of the premises. (Perhaps Goodman will respond by saying that a proposition can appear twice in a set of propositions that is an argument. This seems to treat propositions as tokens of types.) The second objection is that it does not allow for an argument which no one has ever believed to be a good argument (2018: footnote 14). Philosophers sometimes consider arguments which few, if any, people believe to be good arguments, such as the argument involved in the surprise exam paradox. They try to find out what exactly is wrong with such arguments. So why could there not be an argument which no one has ever believed to be a good argument? References Goodman, J. 2018. On Defining 'Argument'. Argumentation 32: 589-602. Walton, D. 1990. What is reasoning? What is an argument? The Journal of Philosophy 87: 399419.