On his blog, Ed Feser offers some amusing versions of the informal fallacies , in this case very informal ones.
Theyre all worth quoting, so I will.
Post doc, ergo propter doc : The delusion that a Ph.D. confers wisdom, or even basic competence. Example: Of course the medievals thought the earth was flat . It says so in the book! Whos the professor here, anyway?
Red hair-ing : Believing that something is true simply because a really hot redhead said it. Example: Omigosh, Christina Hendricks is so hot. I would totally believe anything she says.
Appeal to minority : The smug presumption that popular opinion, tradition, and plain common sense are always likely to be wrong. Often committed in conjunction with the Post doc fallacy. Example: Of course, this goes against everything your parents, your pastor, and pretty much everyone else have always believed. So it must be true!
Question the begging : Knee-jerk tendency to think that panhandlers, hard-up relatives, government employees, etc. are only going to blow any money you give them on booze and cigarettes. Not really a fallacy at all. Example: I dont care if hes a legless veteran with five children and rickets! Didnt you see that iPod?”
Democratic fallacy : Being a member of the Democratic Party and/or voting for Democratic Party candidates. Example: I intend to vote Democrat this year.
Affirming the consequences : Assuming that consequences are all that matter in morality. Also known as consequentialism, and often mistaken for an actual moral theory. Example: Pick any random sentence from a Peter Singer book.
Ad Eminem : Paranoid suspicion among some readers of right-wing blogs that absolutely everything about modern culture leads inexorably to rap music, pornography, and women wearing slacks. Example: Did you read Fesers blog post defending jazz ?! Next hell be linking to YouTube clips from The Marshall Mathers LP !
As long as Im quoting Ed Feser, Ill recommend his superb book on the philosophy of St. Thomas Aquinas, Aquinas: A Beginners Guide . I started reading it on the plane back to Omaha last Friday and couldnt put it down. Feser explains basic concepts in metaphysics very well, and he gives the clearest, most helpful account of the famous Five Ways, the proofs St. Thomas gives for the existence of God, that Ive read. Ive often taught the Five Ways, and after reading Feser Ill do a much better job next time.