What is an Argument?

In common language an argument is regarded as a heated exchange of angry harsh words. It is something that most of us prefer to avoid. Being argumentative is generally not regarded as a virtue.

In logic, though, an argument has special status. An argument is regarded as a related series of statements, of fact, belief or value that lead to a conclusion. The conclusion is meant to follow from or be justified by the statements that lead to a conclusion.

Doug Walton defines arguments as follows:

Arguments can take many forms. In our view, we take an argument in its broadest, most pragmatic sense. Arguments are also only one technique of persuasion. We live in a world permeated with well researched techniques of persuasion. This is the basis of the advertising industry. Argumentation is an appeal to reason, but we need be just as concerned with persuasive tactics that attempt to circumvent reason.

In this course some special terminology will be employed. We will define them now:

	Premise	A premise of an argument is one of the propositions from which together the conclusion is derived.

	Conclusion	The result or proposition arrived at by a process of reasoning.

	Assumption	A proposition is treated as an assumption when it is added to a stock of premises of an argument. The conclusion is then conditional upon that assumption, unless the assumption can be discharged, or shown to be unnecessary, in the course of the argument.

	Enthymeme	An argument in which one of the premises is not explicitly stated.

	Inference	The process of moving from acceptance of some propositions, to acceptance of others.

	Validity	In its primary meaning it is arguments that are valid or invalid, according to whether the conclusion follows from the premises. Premises and conclusions themselves are not valid or invalid, but true or false.

(Blackburn, S. Oxford Dictionary of Philosophy. Oxford ; New York : Oxford University Press, 1996.)

Language and Numbers

Arguments in health care are usually an amalgam of empirical data and narrative claims. In order to understand the complexity of these claims one must be capable of reasoning with both numbers and natural language.

In health care, empirical, or factual claims are usually statistical in nature. Most empirical studies employ statistical techniques as a means of presenting results. Statistics are daunting to many but a rudimentary understanding of statistics is required to make sense of health claims. A series of articles outlining basic statistics for clinicians has been published by the Canadian Medical Association Journal. Statistics are usually used as facts to build up a persuasive case that leads to a conclusion the reader is meant to accept as justified and true.

The process of critical appraisal allows us to make judgments about the reliability of the facts that are put forth in support of a claim. A good example would be "We need more money for breast cancer treatment because one in nine women will develop breast cancer in their lifetime".

In this example, there is a claim that is broadly prescriptive, that is, a claim about how resources should be allocated, backed or defended by data that supports the claim.

In structure the argument would look like this:

Premise:	One in nine women develop breast cancer in their lifetime
Conclusion:	Therefore, more money is required for breast cancer treatment.

It is quite easy on rearrangement to see that the argument is grossly deficient as is and only those who share the belief would accept it in its current form. Clearly the backing does not suffice to warrant the conclusion. More reasons are required. It simply does not follow from the fact that one in nine women develop breast cancer that more money should be devoted to breast cancer treatment. Does treatment make a difference? Are there other conditions that require more attention? These questions point illustrate the fact that the argument as currently stated rests upon unexpressed assumptions that should be articulated in order to make the argument persuasive. The presence of an unexpressed assumption is technically known as an enthymeme.

Secondly, one should be broadly skeptical of facts and acquire the tools to determine their accuracy. Health care debates are replete with facts often accepted uncritically. An excellent exercise is to trace the genesis of facts and to see the rhetorical purposes for which they are used. Returning to the example above, we can ask the following questions:

How was it determined that one in nine women will develop breast cancer in their lifetime?
How was this calculated?
How accurate was the data that was included in the calculation?
Are there any biases that may account for this estimate?
How accurate is the estimate?

Turning to language, we could ask, what does develop cancer mean? Do these women die from their cancer? When in their lifetime will they develop cancer?

In short, to become a good critical thinker requires practice and a commitment to the development of a set of intellectual skills. It requires numeracy and literacy. The effort will pay great rewards as it will provide a depth of understanding and a reasoned skepticism.