Identifying argument form and determining validity

Determine if the argument is valid or invalid and what form it takes. In order for John to keep his job, he needs to come to work on time everyday. John must not have come to work on time everyday because he lost his job. I think it is a valid argument and it is denying the antecedent. Can you tell me if I am on the right track?
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Determine if the argument is valid or invalid and what form it takes.

In order for John to keep his job, he needs to come to work on time everyday.
John must not have come to work on time everyday because he lost his job.

I think it is a valid argument and it is denying the antecedent. Can you tell me if I am on the right track?

Unfortunately, you’ve got it partly wrong. “Denying the antecedent” is never valid. So your answer can’t be completely right. The argument is indeed an example of “denying the antecedent.” But that means that it is invalid. The wording of the argument makes it a little tricky to see this. It will help first to get straight the different argument forms.

First it will be helpful to identify the parts of a conditional (“if … then …”) statement. Symbolically we can represent any conditional statement as having the form:

A  B

Read this as “if A then B” (or, equivalently, as “A only if B”). In this statement the proposition A is called the antecedent and the proposition B is called the consequent.

(It is easy to remember these labels if you think of cognate names. For “antecedent” think of “antecedes” as a synonym for “precedes,” or what comes first / before. For “consequent,” think of “consequence,” or what follows from something that comes before.)

(You should also note that “antecedent” is …