The advocate forwards a claim that in practice (or even in theory) cannot be falsified.
ad hoc explanations; generally refusing to even entertain the idea that their original claim may actually be false (Simple-Minded Certitude).
For example, Turner Round and Benjamin Dover are is discussing a dream:
Turner continues: "…and the snake was slithering around the floor of my car."
Ben offers his interpretation: "Snakes represent transformation, knowledge and wisdom. A snake in a dream is indicative of self-renewal and positive changes."
Turner points out: "Well things are really stable at the moment. And I'm hardly the sharpest knife in the cutlery draw. I think you're full of it mate."
Ben: "Well you didn’t let me finish. The snake also represents hidden fears and worries that are threatening you. Your dream may be alerting you to something in your waking life that you are not aware of or that has not yet surfaced."
Turner replies: "That really doesn't sound right at all. I'm happily married with two kids and no plans for any more. We've just paid off our mortgage and things couldn't be any better at work…"
Ben: "Your not thinking along the same lines that I am…" [At which point he winks at Turner and starts to unbutton his shirt] "Come on man, it's so obvious. Snakes are phallic and symbolise dangerous and forbidden sexuality…?"
Turner: "Dude, what are you doing? Can you please get your hand off my thigh… I don't bat for your team… Not that there's anything wrong with that*.
Ben: "Okay then, but I'm sure I'm right about your dream. It's just that I haven't yet taken into account the car…"
At this point Ben continues with ad hoc interpretations until he eventually works out Turner's dream:
Ben: "Don't you see! The snake and the car are actually in the dream as red herrings, to throw us off the real message. Herrings are a type of fish, and you went ice fishing the day before the dream. But ice fishing represents breaking through a hardened emotional barrier, which is definitely not you. However, fish swim in water, and water is the first part of 'watermelon'. Pregnant women or women on the verge of their menstrual cycle often dream of such fruits. You're a man that's for sure, so it must be the alternative meaning, an association with summertime ease, leisure, and relaxation. It all makes sense; I'm off to Barbados on Wednesday! You were dreaming about me!"
Turner: "Dude, my wife will be here any moment. So will yours. How many times do I have to ask you to keep your hands to yourself? And can you please put your shirt back on?"
Ben has continued to interpret the dream in a way that favours his initial hypothesis; Turner is in denial about his true sexuality. No matter what evidence Turner produces to counter this claim, Ben spins explanation after explanation until his hypothesis is so convoluted that it should be treated with utter disdain. However, if it does turn out that Turner is in denial, and he eventually 'comes out', we have no reason to assume that the dream he had, and Ben's interpretation, was actually correct. It's just a coincidence.#
* c.f. Seinfeld.
# It could be argued that in saying this I've immunised my hypothesis - that dream interpretation is nothing but a waste of time and doesn't reveal underlying psychological issues. But any resemblance between my rejection of dream interpretation even when it seems to work, and the fallacy immunised hypothesis, is also a coincidence.
Tagged - Fallacy Skepticism, Falsification, Hypothesis, Immunised Hypothesis.