It does not use reasons that contradict each other, contradict the conclusion or explicitly or implicitly assumes the truth of the conclusion. Checklist:
- Does the communication include at least one reason to support the conclusion as being true? If not, it is not an argument, but an opinion.
- Could any of the key premises be interpreted as making the same claim as the conclusion? If so, then it’s a “circular argument” without independent reason given to support the conclusion.
- Do any of the premises contradict another premise, or does the conclusion contradict any of the premises?