If she were a spy, she wouldn't admit it. She doesn't admit to being a spy, so she must be one!If she were a spy, she wouldn't admit it. Even if I know for sure she is a spy, it will be no use asking her to confess.If she were a spy, she wouldn't admit it. She says she is a spy, but I think this is a double bluff.
In terms of logic - which is what validity is all about - if it is true that someone will never truthfully admit to being a spy, then we can never get a positive, honest confirmation from them. But this doesn't mean that they must be lying if they deny it.
You can't trust anything she says about health or medicine: she works for a drug company. She's one of them!People who work for drug companies are more likely to be biased in their favour: treat their ideas with scepticism.People who work for drug companies are likely to know what they are talking about: treat their expertise with respect.
Circumstantial ad hominem
It may be sensible to be sceptical (or respectful) based on someone's background, but it is not a general rule that someone's circumstances allow us entirely to dismiss the content of what they say: this is thus a fallacious assertion.
I love eating bananas because they taste so good.Anyone who disagrees with me is an idiot. You say this is nonsense? Obviously, you're an idiot.I know that the Bible is the word of God, because we are told by God in the Bible that this is so.
Round and round
A circular argument provides a conclusion that justifies its initial premise, which then justifies its conclusion, and so on. Only the last of these arguments does this, forming a closed loop of ideas.
She is studious, passionate and creative: she either studied art history or fine arts at university.She is studious, passionate and creative: she studied art history at university.She is studious, passionate and creative: she studied computer science, maths or engineering at university.
Given that general personality traits are a poor predictor of what someone studies, the most likely scenario is the one that encompasses the most possibilities: the last one.
Take a gamble with a 10% chance of winning $95 and a 90% chance of losing $5.Buy a $5 lottery ticket that offers a one-in-ten chance of winning a hundred dollars.Neither is better: they are both the same
The idea of "losing" $5 may feel worse than "buying" a lottery ticket for $5, but both scenarios are identical: they offer a 10% chance of ending up $95 richer, and a 90% chance of ending up $5 poorer.
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