Henceforth shall be basic guidelines for posting.
Avoid making these mistakes.
I. Argumentum ad antiquitatem (the argument to antiquity or tradition): Simply saying, "well that's the way we've always done it" does not a valid argument make. While the Catholic Church is reliant upon Tradition (capital T), it does not mean that every practice, scribble of writing, or school of thought that occurred in years past is worthy of continuing. Thus, if one wishes to rely on the antiquity of a certain idea, one ought point to how the Church shows that this Tradition is held to transcend time as it pertains to the fundamental nature of man, faith or the Church.
II. Argumentum ad hominem (the argument directed at the person): Just nasty. It always finds its way onto the internet. A person will make an argument and quote a source. Inevitably, another person, rather than addressing the point, will misdirect the discussion towards some flaw of that source. Somehow, having made a mistake apparently excludes them from ever making a rational point ever again. EVER. One does not disprove Nietzsche's arguments by pointing out that he ended his life within a mental asylum. Fight the urge to do this.
III. Argumentum ad ignorantiam (argument to ignorance): This is the fallacy of assuming something is true simply because it hasn't been proven false. That is the equivalent of saying, "just you wait and see." This does not form an argument. It merely puts it out of reach of discussion because the commenter has chosen to put in the ethereal atmosphere of the future.
IV. Argumentum ad logicam (argument to logic): The fallacy of assuming that something is false simply because a proof or argument that someone has offered for it is is invalid. Often shows up as the "straw man" argument. Just because your opponent is unable to articulate their side of the argument as well as you does not mean that you are right. Furthermore, exaggeration of an opponent's view point will not prove your point. Thus, "oh, the Pope just wants to have everyone go back 50 years." Well, that may or may not be. It doesn't prove your point for liturgical dancers.
V. Argumentum ad misericordiam (argument or appeal to pity): This is often used in issues such as abortion. A objective review of a the situation and moral implications often gets side tracked by, "what about cases of rape!" The sin of rape is so profoundly evil, that it overwhelms our senses and we often react viscerally to this reality. It then becomes impossible to rationally continue the debate, because if you are against abortion, you are against women who get raped.
VI. Argumentum ad nauseam (argument to the point of disgust, i.e. by repetition): Just because you've found Ctrl + C + V does not mean your argument is valid. No matter how many you repeat something, if it was wrong the first time, it'll be wrong the 100th time. Also, the idea that all arguments go back to one root cause. The pope comes out with a book on Jesus, inevitably, someone will say, "well, he should be focusing on the sexual abuse crisis" (a real comment).That may or not be, but it has nothing to do with the subject at hand. Likewise, not all problems of the world can be solved by going back to the Extraordinary Form of the Mass. You know who I'm talking to. I'm going to need you to step away from your computer, go get a drink of water, and fight the urge to reply.
VII. Argumentum ad numerum (argument or appeal to numbers): It's like your mom said, "just because everyone else is doing, doesn't make it right." Truth is not a democratic consensus. It doesn't matter how many people are Yankee fans. It doesn't make them right. (Feel free to discuss amongst yourselves). SEE ALSO argumentum ad populum. Often times, someone will say, "well, 55% of Americans think that homosexuals should be allowed to marry." Well, that might be. But what does that have to do with the Church. If 55% of Americans thought it was acceptable to steal from one another, would that make stealing right?
VIII. Argumentum ad verecundiam (appeal to authority): Just because someone famous says something doesn't make it true. For example, if Stephen Hawking were to come out with a book on cooking, no one would think that this was a great truth just because he's an exceptional physicist. The same should be applied to theology. Just because someone who is an expert in one field makes a statement about God does not make it true. If you are going to quote someone, make sure they have the (1) the corresponding knowledge and (2) the authority to make the statement. So, my friend can tell me that it's morally acceptable for me to skip work, but it doesn't give him the authority to do so. You need your boss to think its ok for you skip work.
IX. Circulus in demonstrando (circular argument): "You shouldn't smoke pot because it's illegal. It's illegal because it's bad for you. It's bad for you to smoke pot because if you do, you'll break the law and go to jail." Anyone see the fault here? Also similar to the petitio principii (begging the question).
X. Cum hoc, ergo propter hoc (with this, therefore because of this): This shows that because one thing happened, another thing is happening. So, if the economy is doing well, it must be because the President's economic policies are just wonderful. Well, maybe they are, and maybe they're causing the economy to do well. But there is nothing in the argument that proves or disproves that point. It is always fallacious to suppose that there is a causative link between two things simply because they co-exist. SEE ALSO, post hoc ergo propter hoc. This happened, thus because of this. E.G. Priestly vocations decreased after the II Vatican, therefore, II Vatican council caused a decrease in priestly vocations. Again, no actual argument is made other than a loose chronological order of relation.
XI. Dicto simpliciter (spoken simply, i.e., sweeping generalization): This is when one finds a pattern of behavior and then applies it universally. Example: "Women are on average not as strong as men and less able carry their weight. Thus, women should not serve in combat." While it is true that on average, women are not as strong as men, there are numerous examples of women who are as strong and stronger than some men. Thus, the argument has not been made.
XII. Non sequitur ("it does not follow"): Drawing conclusions from a statement of facts that do not follow. "People without insurance is bad. Thus, we need universal healthcare." Maybe, maybe not. The fact does to support the conclusion thought.
XIII. Red Herring: When you use a statement that does not pertain to the argument to draw people's attention away from the fact that you just got owned. Example: "So, as you see, from x, y, and z, the current spending of entitlement programs cannot be sustained in the immediate future." Red Herring: "So I suppose that it doesn't matter that the elderly will die without healthcare." While it is important to discuss the needs of the elderly, this fact does not have a relevance on budget solvency.
XIV. Slippery Slope: Attempts to make an argument based upon a chain of consequences which will result from granting the point in focus, without showing a causal connection between the advocated policy and the consequent policies. Example: "If you legalize marijuana, you might as well just go ahead and legalize all drugs." Closely related to the non sequitur.
XV. Tu quoque ("you too"): This is the fallacy of defending an error in one's reasoning by pointing out that the opponent has made the same mistake. In moral theology, it often comes out, "well, listen, we've all sinned, so really what I'm doing isn't that much worse from what you've done." Parents often hesitate to talk to their kids about drinking because they feel hypocritical for admonishing an action that they themselves engaged in as a kid. It doesn't mean that the argument is without merit.