Understanding the structure of arguments is important because it enables a reader to critique various works effectively. Arguments consist of two main parts: conclusion and evidence.
Socrates is human (premise) → Socrates is mortal (conclusion)
In this common argument, one concludes that Socrates is mortal because he is human (as humans are, in fact, mortal). In this example a single conclusion/claim is drawn from a single premise. However, most of the arguments readers of academic literature encounter are a lot more complicated with numerous reasons given in support of an assertion, and the assumptions that may hold them together may be difficult to uncover.
A slightly more complex example might look like this:
The example above gives four reasons in support of the main claim. This could have been a lot more complex; one could add six more copremises and significantly increase the justifications. The most important part of the analysis for the critical reader is to determine whether the reasons given really support the main point. For instance, one may ask whether violating important principles of international law by keeping GITMO open would really undermine America’s reputation.
Readers of social science literature sometimes have a difficult time distinguishing between an argument and an explanation. The former is, as noted earlier, a combination of assertions supporting a central claim; the latter is a description of the circumstances or an interpretation of given information. Thus, one cannot use an explanation to support a claim. For instance, one might say that the increase in teen pregnancy in the US can be explained by the permissive media culture, willingness to take risks in sexual relations, or moral decline. Although these explanations are certainly interesting and may even be true, they are not evidence. One would need to go further and try to provide some sort of empirical evidence to support the claim.
There are generally two types of arguments: inductive and deductive. A deductive argument is one in which the premises guarantee that the conclusion is true. These occur when, perhaps by mathematical or definitional necessity, the truth of the premise will definitely determine the truth of the conclusion. An inductive argument, on the other hand, is one in which the premises provide a sufficient reason for a reader to believe that a conclusion is likely to be true. The difference between the two is the level of certainty that can be ascribed to each one. One can be certain that the conclusion of a deductive argument is correct while one can bet that the conclusion of an inductive argument is probably correct. Most of the arguments encountered in social science literature will be inductive as scientists (a) seek to find possible explanations for varying phenomena, (b) use statistical data to make inferences regarding large groups based on what is found to be true of smaller ones, or (c) try to find a causal relationship between two or more variables.
A deductive argument is considered valid or invalid. It is valid when it has the right form regardless of whether or not its premises are true. For instance:
All fish can run.
Anything that can run can fly.
Therefore, all fish can fly.
Although the two premises in this argument are false, the argument is logically valid. This means it is possible to have a valid argument that has false premises and a false conclusion. Validity simply means that if the premises are true the conclusion must also be true; it does not mean that the premises are true. Thus a deductive argument with false premises and a true conclusion can be valid. For instance:
All fish have smooth skin.
Anything with smooth skin can swim.
Therefore, all fish can swim.
In an invalid argument, the conclusion does not necessarily follow from the premises. It may look like this:
All American presidents live in Washington, DC.
John lives in Washington, DC.
Therefore, John is an American president.
In this example, the premises may be true, but the conclusion is false. A key point to note is that invalid arguments are unsound. When one combines true premises with a valid argument, the argument is said to be sound.
Inductive arguments, on the other hand, are described as either strong or weak, depending on the strength of the premises/information provided to support the conclusion. Therefore, by definition, valid arguments cannot be strong and vice versa. One can, however, speak of any argument as being valid or invalid. If an argument is valid, one may ask whether it is sound or unsound. If you understand the structure of a writer’s argument, the easier it will be to critique. See our section on logical fallacies.
Critical reading has a lot to do with evaluating the strengths and weaknesses of arguments. Because graduate students are generally expected to critically assess what they read, simply having a sense of what might be wrong with an argument is not enough, they must be able to identify precisely why an argument may be weak. As a general rule, the stronger the claim, the stronger the evidence provided in support of it must be. It is one thing to say poverty contributes to war and entirely another to say poverty causes war. One would require stronger evidence to support the latter claim than to support the former. Both critical readers and writers must learn how to strengthen and weaken arguments. Writers who master these skills are able to write authoritative and convincing material and readers who master these skills are able to critique such material. By learning how to effectively identify assumptions, one is well on the way to evaluating arguments effectively.