> there's a lot of arrogance in the claim that anyone should be able to easily and automatically rule out the existence of some species based on their personal knowledge

some, certainly yes.

i don't think anyone would disagree that some claims are more plainly ridiculous than others. i'm replying to someone who let themselves be convinced the tree octopus was real by a page picturing an octopus climbing a tree. let's not abdicate our regard for common sense.

I think you'll find your idea of "common sense" is perhaps not so universal as you think.

For example, why is a tree octopus any less likely than the platypus, a venomous aquatic mammal that has a beak, lays eggs, and detects prey by sensing electric fields like a shark?

The reason the tree octopus as described by that page seems obviously, totally fake to me is the absolutely janky "photo". Let's count the issues:

1) obviously photoshopped -- a real octopus on a tree branch would look totally different, it would sag in some places, it would affect the pine bristles underneath, it wouldn't have a shadow that makes it look like it's hovering an inch above the branch, etc. Also, that octopus image looks totally out of proportion, but I can't pin down why -- I _think_ it's because the level of detail is higher than for the branches.

2) It looks exactly like a regular octopus. Not only should an animal the size of a small bird have different proportions from a regular octopus (compare e.g. bats and fruit bats, or cats and tigers), but it should also look only distantly related to a regular octopus because it's adapted to a totally different biome.

All that leads me to the following conclusion: Common sense, in the sense of broadly understanding how the world works, really is what prevents you from getting fooled, and the more things you understand, the less likely you are to get fooled. Also, the more information a hoax has, the more likely it is to get exposed, because just one sufficiently glaring inconsistency can sink it.

Platypus seriously? If you're going to make up an animal, at least try to give it a realistic sounding name.

See, if they had said the tree octopus is found in some remote corner of Australia and has a pouch to raise its young, more of us would buy it...

call me arrogant but i won't stoop to the level i have to be at to take your question seriously.

do i think i'm as intelligent as anyone, or that everyone is as intelligent as me? of course not. but i do think your standard for gullibility is too high if you don't think believing the linked article satisfies it.

Stoop? I challenge you with a perfectly valid example of an unlikely animal, and your response is to claim I'm somehow, what, failing to argue at your level?

I suppose that's enough to make my point for me.

you asked me how i would ascertain that an animal documented to exist is more likely to be real than a hypothetical animal depicted with _a photoshop of a different animal climbing a tree_, as if there is no reasonable expectation of intelligence or intuition for an abled, functioning adult

the difference between people who initially believed this and those who didn't is gullibility, and this is a great example of gullibility because of how outlandish the claim is and appears to be. that's all i'm arguing. the counteraguments i see boil down to "but if someone is gullible enough, they'll think it's actually not outlandish and accept it on face value" which is not contrary to what i'm saying.

if you were one of the gullible ones, sorry! sucks to be more deficient than others in some way, but we all have deficiencies.

I think the point is that it seems highly unimaginative (or perhaps just highly unempathetic, if there's a difference in this situation) to not see how a casual reader could just take it at face value and go on with their day. This seems especially plausible to me if I think of someone who knows little of the natural world beyond the odd thing they've come across on the internet, doubly so if not from America. At face value it seems as plausible as anything else, with just a bit of scrutiny it clearly doesn't hold up.

But I suppose you have your deficiencies too, same as those who thought it to be real (however briefly).

Which of the following are real?

- Tree lobster - Tree crab - Tree clam - Tree fish

you're presenting an entirely different scenario from the OP. try again with photos, maps, propaganda posters, and a few thousand words on each, and replace your question with an assertion. in absence of that i do a quick search and find out three are real and one is not but may be a colloquial term referring to a sporadic phenomenon

And the first time I read about those crabs, I checked Wikipedia to see if they were real too. Too many hoaxes on the Internet, but most of them are trivial to find out if they're real.