My parents were Owen and Constance

My parents were Owen and Constance Papineau.Could I have had different parents?Surely not.A Person with different parents would not have been me.So it is necessary that David Papineau's parents were Owen and Constance Papineau.But this statement is surely not a priori.You need evidence to know who my parents were.It's not something you can find out just by thinking.So that's one emample of an a posteriori necessity.
Here is another.Hydrogen is made of atoms containing one electron.This is surely necessary too.Hydrogen couldn't have had a differentatomic structure.Anything with a different atomic structure would't be hydrogen.But this statement too is obviously a posteriori.Physicists didn't figure out the structure of hydrogen by sitting in an armchair.They needed to perform a great number of detailed experiments and observations.
Perhaps the most obvious examples of a posteriori necessities are simple identities involving proper names.Marilyn Monroe is Norma Jeane Baker.This again is necessary.Marilyn Monroe couldn't not have been Norma Jeane Baker.That would require her somehow not to have been herself,which would be absurd.But Marilyn Monroe is Norma Jeane Bakers not a priori.Somebody could understand this statement perfectly well and yet not know it is true.(Imagine someone who grew up with Norma Jeane but lost touch with her,and had heard of Marilyn Monroe but not seen any of the films.)

結果 (中文) 1:

我的父母是欧文和康斯坦茨 Papineau.Could 有过不同的父母吗?当然不是。一个人和不同的父母会不是我。因此它有必要 David 米诺的父母是欧文和康斯坦茨 Papineau.But 这句话是不是先天。你需要知道我的父母是谁的证据。这不是你可以找出只是由思维。所以这就是一个李玲的后验概率必要性。这里是另一个。氢气是由包含一个电子的原子组成。这也是肯定有必要。氢不可能有一个 differentatomic 结构。任何与不同的原子结构也不肯是氢。但这种说法太明显后验。物理学家们搞不清的氢结构坐在扶手椅上。他们需要执行大量的详细的实验和观察。也许后验必需品最明显的例子是涉及专名的简单身份。玛丽莲 · 梦露是诺玛珍 Baker.This 又是必要的。玛丽莲 · 梦露不是诺玛珍 Baker.That 会要求她不知何故没到过自己，这将是荒谬。但玛丽莲 · 梦露先验不是诺玛玛面包师。有人能完全理解这句话，却不知道这是真的。(想象一个人长大的诺玛-琼但失去联系到她，和曾听到玛丽莲 · 梦露却看不见任何一部电影)。

結果 (中文) 3:

我的父母是欧文和康斯坦斯骨髓炎。我可以有不同的父母吗？当然不是，不同父母的人不会是我。因此，戴维骨髓炎的父母欧文和康斯坦斯骨髓炎。但这肯定不是一个先验的。你需要证据来知道谁是我的父母。这不是你能找到的只是思考。这是一个例一个后验概率的必要性。这里是另一个。氢是由含有一个电子的原子。这肯定是必要的。氢气不可能有differentatomic结构有不同的原子结构的任何东西都不能氢。但这种说法太明显的后验概率。物理学家不知道氢的结构，他们坐在扶手椅上。需要进行大量细致的实验和观察。也许一个后验必然最明显的例子是简单的恒等式的正确名称。玛丽莲梦露诺玛·琼·贝克。这又是必要的。玛丽莲梦露不能没有诺玛·琼·贝克。这需要她没有自己，这将是荒谬的。但玛丽莲梦露的诺玛面包师不一先验的。有人能理解这句话很好，但不知道它是真的。（想象一下，人长大了诺玛但是她失去联系了，听说过玛丽莲梦露，但没有看到任何电影。）