Argumentum ad populum You tell your friend that the claims he’s making are pretty absurd and that he has no evidence for them whatsoever.
Instead of addressing the issue, he tells you that if they were so absurd, 1.6 billion other people wouldn’t believe in them.
Congratulations, you’ve unfortunately just been served argumentum ad populum.
Apparently just because 1.6 billion people believe in something, it must be true.
According to the same logic, the world must have been flat a few thousand years ago since a lot of people believed in that too.
2. Anecdotal evidence Your friend tells you that her grandma onlyate carrots her whole life and she lived to be a 109 years old.
You tell her, “Okay, cool.
Good for her.”
But she’s not content with that.
She wants you to only eat carrots as well.
If her grandma had such great results, you’ll surely have great results as well.
You tell her that you look at evidence through scientific studies involving large sample sizes for what is ideal to eat but she doesn’t understand.
In her world, smoking is beneficial since there’s a 109-year-old smoker somewhere in the world right now without lung cancer.
3. Correlation proves causation A friend of yours tells you that he started using this new soap and his acne have been getting much better.
You realize that that might very well be true, but you’re also skeptical.
You share this with him and he gets mad.
What do you mean?
He knows for a fact that ever since he started using this soap his acne have been getting better.
You tell him that yes, while that could be true, it could also be because we’re getting more sun now cause it’s the summer.
He changed his diet a little while ago, and that also might be affecting it.
He also got a new job and might be less stressed.
You bring up all these points and tell him that even though the soap could be legit, you can’t really say for sure.
He’s still mad.
He doesn’t understand that correlation does not prove causation, especially with his impressive sample size of 1.
4. Wishful thinking Your friend tells you that he loves the thought of being massaged by the spaghetti monster and his tentacles for eternity.
You ask him if he has a reason to believe in something like that.
He tells you that it’s so consoling to him.
What is your alternative?
You die and then there might be nothing?
All you can tell him is, “I don’t know?”
That kind of uncertainty sounds terrible and isn’t very consoling, therefore the whole spaghetti monster gently caressing you for eternity thing must be true.
5. Shifting the burden of proof A friends of yours tells you that Zeus exists and that he is the one true God.
You ask him if he has any reason to make that claim or if there’s any way he can prove that statement.
He laughs at you and tells you, “Well, how about you prove that he doesn’t exist.”
You tell him you can’t do that, just like you can’t disprove that there isn’t a teapot orbiting somewhere around the sun right now even though we would never just assume that a teapot like that existed.
He laughs again and says, “See… You can’t disprove it therefore Zeus exists.”
You want to bring up the point again that the burden of proof lies on the person making the claim but at this point you hopefully realize that you’re not really going anywhere with this and perhaps have an even more important realization that you really need some less shitty friends.