Causal arguments focus on discussing the cause of a specific event or situation, such as a doctor explaining why smoking is the likely cause of a patient's lung cancer. A causal argument can also be referred to as a cause and effect argument.
If two people are having a discussion about how a war began, they are engaging in a causal argument. The word "argument" doesn't necessarily refer to disagreement in this case, but it can mean that someone is making a case for a specific factor or set of factors being responsible for a specific outcome. Causal arguments examine the "why" and "what if" factors of a certain scenario. Causal arguments can be based on speculation and can be full of mistakes, especially if the person making the argument doesn't have enough evidence to support their claims.