Evaluating Arguments, Part 1: Introduction and General Dichotomy

Arguably the most important aspect of critical thinking is the ability to analyze and evaluate arguments. While this new series will serve as a continuation of the critical thinking series recently concluded, I thought that the importance of argument evaluation warrants its own series. This post will introduce the structure and purpose of this series, and will also provide a general dichotomy which can be used to evaluate arguments.

A precondition of argument evaluation is argument analysis. To analyze something is to break up a whole into its parts, to examine it in detail so as to determine the nature of and relations between concepts. For argumentative purposes, this usually consists in formulating the argument in syllogistic form, meaning identifying the premises, the relations between them, and which conclusion (if any) follows from them. Be sure to break down the argument into its component propositions, and propositions into component terms or concepts.

Following the analysis is argument evaluation. While analysis serves mostly to give a better understanding of an argument, evaluation actually forms a judgement on its rational coherence and persuasiveness.

So, how does one evaluate an argument?

First, determine if the argument is valid or invalid. The latter means that the argument has a faulty structure. The truth of the premises, when an argument is invalid, does not guarantee the truth of the conclusion.

Example of invalid arguments:

Affirming the consequent

• If A, then B
• B
• Therefore, A

Denying the Antecedent

• If A, then B
• ~A
• Therefore, ~B

If the argument is determined to be valid, determine the truth value of its premises. If they are all true, then the argument is sound.

This general dichotomy is an immensely valuable tool, however argument evaluation is much more complex than merely stating “this argument is unsound.” We must specify the precise ways in which arguments can be unsound. And it’s that very question that will be the focus of this series.

Each post in this series will look at one or more ways to address an argument, which is the very core of argument evaluation. The posts will first describe the technique, then give one or more real-life examples of how the technique can be applied.

Since there are so many ways an argument can go wrong, this series will mostly focus on ways to critically assess arguments. This series will hopefully provide all rational thinkers with a comprehensive tool kit for evaluating arguments.

Author: Joe

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