Hi there. I need help deducing an argument form in formal language, but I am not sure that I can communicate the example very well, nor even that it can be expressed in a formal language for that matter. The case at hand: Rene is a cat. Julie is not a cat. Therefore, julie is a human. Or: People have died paragliding. Bruce is going paragliding. Therefore, bruce is going to die. Of course, both of these examples are incorrect as they draw conclusions that are not necessary consequences of their premise. I guess what I am after is simply a counterexample to this sort of case where the conclusion is not necessarily true, even though there can be cases in which it is. How would you express such a counterexample in a formal language? EDIT: How does one go about writing the language anyway? How do the guys here write down mathematical equations when none of the components exist on normal keyboards?