Monthly Archives: March 2013

Formally Valid Non Sequiturs?

One common conception identifies logical fallacies with arguments “that seem valid, but are not.” This definition is difficult to sustain however, because there are arguments so obviously fallacious that they would probably would not trick anyone with their “seeming validity.” While there are fallacious arguments that are invalid, there are examples of fallacious arguments that are valid, while others are even sound. In order to notice these examples, and identify their logical shortcomings, we need to use the tools of informal logic, not being content to let formal validity or formal fallaciousness decide the ultimate logical disposition of a given argument.

Formal Fallacies – Fallacies of Relevance?

What is wrong with this argument?

(P1) All collies are animals.
(P2) All dogs are animals.
(C)  Therefore, all collies are… Continue reading