an argument may be seen as the foundation on which the conclusion is built. According to this analogy, two things can go wrong and turn an argument into a fallacy. It could be that the foundation is shaky. But even a solid foundation is not helpful if it does not provide support for the conclusion in question.

Traditionally, fallacies have been defined by three necessary conditions: "a fallacy (i) is an argument, (ii) that is invalid, and (iii) appears to be valid." This definition covers only formal fallacy since it has deductive invalidity