Argument assessment

In order to assess the quality of an argument, go through the following steps:

  1. Is the conclusion and each reason a proposition? Explanation: A "proposition" is a statement that has a truth value, that is, from a grammatical point of view it can be true or false (or something in between). A question or a command, for example, is not a proposition, nor is an incomplete sentence. Every component of an argument (reason or conclusion) must be a proposition, or must be transferrable into a proposition (the latter is relevant for visual arguments)
  2. Is the meaning of the conclusion clear? Explanation: If a conclusion is vague or ambivalent, it is impossible or difficult to determine the quality of its justification. Also, unclear formulations open the door for all kinds of biased interpretation. This is very important. Keep in mind that you might think the formulation is clear (that happens when you are biased) even though different interpretations are possible.
  3. Is the conclusion a simple proposition or a proposition that is composed of several components? Explanation: "Several components" means that the conclusion can be divided into a list of propositions, that is, complete sentences, each with its own truth value.
    1. If composition:
      1. Check for each component of the conclusion whether there is at least one reason that justifies this component. Every component needs to be justified.
      2. For each component, do what is described under Step 3.2
    2. If simple proposition:
      1. Check whether the formulation of every reason is clear enough to do Steps 3.2.2 to 3.2.4. Explanation: (A) Sometimes reasons are vague or ambivalent or simply badly formulated. (B) Sometimes reasons have several components, each with its own truth value. One component might be true, the other false, so that Step 3.2.2 cannot be decided. In this case, divide into several reasons. (C) Sometimes a reason contains itself an argument. In this case, divide the reason statement so that the entire argumentation becomes visible as a chain of arguments.
      2. Check each reason that is provided to justify the simple proposition: Is this reason in itself true or at least acceptable, or is it justified by a further argument? Every reason must be either true, acceptable, or justified by a further argument.
      3. Check whether each reason that is provided to justify the simple proposition is relevant for this proposition. Explanation: It is quite often the case that there simply is no relation between reason and conclusion. Also, sometimes a reason simply repeats the conclusion or claims the same with different words.
      4. Check whether all the reasons provided to justify the simple proposition are sufficient to justify it. Is something missing? Note: It is quite often the case that we accept reasons as sufficient based on additional background assumptions that are trivial or self-evident but not explicitly stated as a reason. This is often acceptable and does not necessarily decrease the quality of the argument. But if you think about this question, you might just as well make these implicit assumptions explicit.
      5. If several reasons are provided, check whether each of them (or certain groups of reasons) could justify the simple proposition independently from the other reason or reasons. Explanation: See the distinction between co-dependent reasons and independent arguments. The point is: Since an entire argument can be defeated by refuting only one of several co-dependent reasons, it is always better to provide a series of independent arguments for a conclusion. But be careful: Often reasons need to be co-dependent in order to be sufficient to justify the conclusion.

Michael Hoffmann, June 7, 2017

Note: Steps 3.2.2 through 3.2.4 represent the so-called ARS criteria (Acceptability; Relevance; Sufficiency), as described by Ralph H. Johnson and J. Anthony Blair, Logical Self-Defense (New York: International Debate Education Association, 2006 <1977>).