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is drinking a Coke right this minute. Assuming the premise is true the conclusion is probably also true so it is a strong argument. Now, is the premise really true? Sure. So, the argument is also cogent.

But what about this one? Harry will never be able to solve that difficult problem in advanced calculus in the limited time allowed. He has never studied anything beyond algebra and in that he earned on a C minus. Here is another strong argument since if we assume the premise is true (that he never studied anything beyond algebra and in that he earned on a C minus) the conclusion is probably also true. But, when it comes time to assess cogency we no longer assume the premise is true. We need to determine whether the premise really is true. Is it? Again, I would ask you to consider how you would know this. Do you know Harry? No. So, here is a case where cogency cannot be determined.

To this some students will reply: Well, then soundness and cogency can never really be determined. But, we've already seen examples where we can easily determine soundness and cogency so this is not the case. My only point is that there are arguments where the truth of the premises cannot be established. That is to say, no one could know whether they are true or false. Please note that this is different from the problem you may run into in some examples where you personally do not know whether the premises are true or false. If you personally do not know, that does not necessarily mean that soundness or cogency cannot be determined. It may simply mean that you cannot determine them. In practical terms, this may be a problem for you on the exam since I will expect that in cases where soundness or cogency can be determined, that you be able to determine it. A few examples may clarify this point.

Every map of the United States shows that Alabama is situated on the Pacific coast. Therefore, Alabama must be a western state. This inductive argument is strong since the conclusion follows from the premise assuming the premise is true. Is it a cogent argument? You may not know and so you may think the answer is that cogency cannot be determined. However, this is a case where cogency can be known (whether you know it or not). It is false that every map of the United States shows that Alabama is situated on the Pacific coast. In fact, it is quite likely that no maps show this (and you should know this as you should know where Alabama is really located!). So, this argument can be determined and is uncogent.

How about this one? The United States Congress has more members than there are days in the year. Therefore, at least two members of Congress have the same birthday. This deductive argument is valid since the conclusion necessarily follows from the truth of the premise. So, now we need to determine soundness. Can we? Yes. The premise is true so the argument is sound.

But, what is the difference between these examples and the ones above that were undetermined? Look at the example with Raquel and Tom. There is no reason anyone should be expected to know who these people are. How could you ever know this? This is why soundness cannot be determined. However, in the example about Congress it is clearly knowable by someone and I maintain it ought to be known by everyone in the class as an educated person.

So, please be aware of these issues as you work through section 1.4 in the text. Take care to note the cases where soundness and cogency can be determined but also be aware of cases where they cannot. In such cases recognize that there is no logical basis for making a determination of soundness or cogency and refrain from doing so.

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