Lessons in logic: formal parts of an argument

Posted by mouthyb | Posted in | Posted on 2:15 PM


Once you are sure that you are in the presence of an argument, it can be useful to be able to consider the contents of the argument piece by piece. There are several parts and terms used to describe the contents of an argument: the first is the overall veracity of the argument, assessed in terms of truth values.

Truth value, roughly, is the ability of a given statement (factual claim or inferential claim) to be verified by a source known to be accurate or by the ability to be reproduced across the experiences or under the conditions given in the original claim.

Example: (factual claim) Obama's policies caused the recession we're currently in.

I'm just going to go ahead and tell you that explanation is false. The overall status of the truth claim of an argument is typically determined piece by piece, through checking the claim against peer-reviewed or otherwise trusted sources, with the odds of overall falsity rising with each not true claim discovered.

The argument itself is divided into two general categories, premises and conclusions. This corresponds to the original factual (premises) and inferential (conclusion) label for the claims. The factual and inferential label is used to characterize the nature of the thing being looked at, whether it is a complete argument. The labels premises and conclusion are used inside the argument, once you understand it to be an argument.

A premise is defined as a statement which attempts to set forth reasons or evidence for establishing or believing the accuracy of the conclusion.

Example: Roosevelt's New Deal provided public aid which helped the US re-emerge from the Great Depression.

The conclusion is defined as the statement that the evidence given in the premises purports to support.

Example: We can conclude, since the New Deal helped the US in a similar period of economic uncertainty, that Obama needs to enact his own New Deal.

The nice thing about conclusions is that they employ a relatively stable terminology inside argument. Conclusions are typically distinguished by the use of the following words/phrases:

'therefore,' 'wherefore,' 'accordingly,' 'we may conclude,' 'hence,' 'thus,' 'consequently,' 'it can be inferred that,' 'whence,' 'so,' 'it follows that,' 'as a result,' and 'it must be that'

We have a little problem with the premise and conclusion set, however. The premise is inadequate to support the conclusion. For the purposes of formal argumentation, all of the compenents of a conclusion must have factual, true support in the premises for the argument*. Few arguments manage to be factually accurate and persuasive without at least a handful of premises.

The least number of premises necessary for proof is three, though they may be reliant on one another, or even implicitly expressed. The gold standard for formal argumentation, however, limits the number of major premises which can be implicit.

The next lesson will be on interdependence between premises and conclusions, and constructing well supported, formal and informal arguments.

*There are several ways to not have to provide this support in social argumentation; the case I'm setting up is only the formal. In cases where the audience is already in partial or total consensus, the proof burden on the arguer is reduced.

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