I dont understand something and it's making me feel stupid

i dont understand something and it's making me feel stupid

my friend says that "all pigeons are birds" doesnt mean that "all birds are pigeons", but if its all pigeons, then how can he be sure? he tells me it's a logic rule, but i dont understand

It means that there are other types of birds apart from pigeons.
Alternatively, pigeons can't be of other types of animals but birds.

nigga have you never heard of seagulls? Those are birds, but they're not pigeons. q.e.d.

a square is a figure with four parallel sides. it can be argued that all squares belong to the group of shapes we call rectangles

however, not all rectangles have four parallel sides of equal length. equal length is what defines a square. so not all rectangles are squares.

all M&Ms are candy, but not all candy are M&Ms.

now, if the only birds in the sample set that you're talking about are actually pigeons, then yes, all the birds are pigeons. obviously, pigeons are a type of bird, all pigeons are birds.

but not EVERY bird in existence is a pigeon.

piegons is a subset of the set of all birds.

we argued about that already, but what i said is that "all pigeons are birds" means that there are no seagulls, but since i know there are seagulls (i have seen them with my eyes), then that just means the thing i supposed must be false, so not all pigeons are birds, and then he called me stupid and ignored me for a while

all humans are mammals

does that mean that humans are the ONLY type of mammal, or that mammals are the only type of life on earth?

i would say it means that not all humans are mammals

Please stop, you are shattering my universe coherence.

okay this is actually fascinating to me

when you see the phrase, "all humans are mammals", which is fact, how do you read it as "not all humans are mammals"?

I think there's something seriously wrong with how you parse the english language.
Do you think the sentence "every pigeon is a bird" is true or false?

i dont read it like that, i just think that if it's true, then it leads to the second one, so it cant be true

i think it makes sense and is probably true, but the logic says it is false

I think he's trolling but I've known people who spend an entire semester on logic and still don't get that [math] P \rightarrow Q [/math] does not imply that [math] \neg P \rightarrow \neg Q [math]

Op are u a bird?? You baffles my tiny brain

> OP is a brainlet that needs help
> come here to help brainlet because clever
> brainlet so brainlet he defies the laws of logic
> cause space-time inversion that makes him the most clever one
> all clever posters becoming brainlet
> therefore,
brainlet -> not brainlet
clever -> not clever

>i think it makes sense and is probably true
yeah
>but the logic says it is false
how so?

Is English your native language?

Obviously not, since that would mean nobody has english as a native language.

you dont have to be rude, i already know im stupid, i just want to stop being

ok, heres an example with fruit

all apple is fruit

same as
all fruit is apple

but
i have tasted orange (i have put it in my mouth)

so
all apple is fruit
must be false

so some apples are not fruit (vegetable, for example)

no, but i understand english well

>no, but i understand english well
Where you from then? Maybe all of this actually makes sense in your native language (it doesn't in english).

>so some apples are not fruit (vegetable, for example)
lmao
I was gonna try and explain how it works but I can't wrap my mind around this logic

I know this is probably a troll, but I'll give it a shot anyway.

Imagine I have two sets of birds, pigeons and sparrows.

All of the pigeons are birds. All of the sparrows are also birds.

Not all of the birds are pigeons. Because some are sparrows.

Does that make sense?

>no, but i understand english well
Sorry to inform you, but no, you don't.


>all apple is fruit
>same as
>all fruit is apple

In English, those two statements are not the same. They are totally different.

Imagine a big box of fruits that contains two smaller boxes inside, one with apples and other with oranges. Now any apple you take from the apple box will obviously also belong to the big box of fruits, so every apple is a fruit. If you take a random item from the big fruit box, you can get an orange or an apple, thus not all fruits are apples.

does this help?

I can't tell if you're a troll, brain damaged, or seriously lacking in the logic department

pigeon -> bird
does not imply
bird -> pigeon

The statement "All Veeky Forums posters are retards" does not imply "all retards are Veeky Forums posters".

>english is a language
>not all languages are english
>not all of english is language
>all of english that is not language is still definitively english
>english is partially language

if english is only partially language, what is not, is still part, what isn't is still wholly language, but what is is partially still part, but not fully language, while fully english, but not fully partial in, but that which is partially nonlingual while wholly english but not full in partial linguality while not english, added to the whole, gives a partially full nonenglish, a fully partial english nonlanguage, a fully nonenglish partial language full part, & a wholly language nonpartial part english nonlanguage wholepartial partenglish remainder.

it can be reasoned that there is in fact no set of partial fully whole language nonenglish entities that are not also their wholly full partial nonlingual english equivalents

ok now I KNOW you are trolling

Has anyone really been far as decided to use even go want to do look more like?

What does quantum electrodynamics have to do with seagulls?

op, if not trolling, is proof that logic rules are man-made and do not exist in the universe independent of our minds.

btw what's the difference between a pigeon and a dove?

If a pigeon eats an apple, are all birds english?

I don't know, in my language we have just one word for them (duif).

'Dove' is not a biologically meaningful term, It just refers to any white variety of pigeon.