G. E. 摩爾在1903年發表《倫理學原理》，以語義探究倫理學，開創元倫理學。摩尔探究倫理學的概念「好」（good），认为「好」的概念无法与任何经验事实（例如令人愉悦）等价，因此认为「好」无法定义，並借此指出了伦理自然主義的謬誤。[10]
A. J. 艾耶1946年的著作《語言、真理與邏輯》提出情緒主義，用邏輯實證主義的檢驗原則否定倫理學。该书認為道德價值「好」，不可以用經驗檢證。他指出道德句子表達的是情緒，而非认知意义，因此非真非假，没有真值。[11]不過，21世紀有哲學家質疑邏輯實證主義的基礎。林火旺认为，艾耶情緒主義的論證基礎有問題。艾耶情緒主義的論證基礎是「檢證原則」，但「檢證原則」不可以檢證出「檢證原則」本身。因為「檢證原則」主張如果有意義的命題不是分析命題，就是可以檢證的綜合命題。當「檢證原則」嘗試檢證「檢證原則」本身，就會得出「檢證原則」本身是沒有認知意義[12]。
^
"Without exception, the best philosophy departments in the United States are dominated by analytic philosophy, and among the leading philosophers in the United States, all but a tiny handful would be classified as analytic philosophers. Practitioners of types of philosophizing that are not in the analytic tradition—such as phenomenology, classical pragmatism, existentialism, or Marxism—feel it necessary to define their position in relation to analytic philosophy." John Searle (2003), Contemporary Philosophy in the United States in N. Bunnin and E. P. Tsui-James (eds.), The Blackwell Companion to Philosophy, 2nd ed., (Blackwell, 2003), p. 1.
^See, e.g., Avrum Stroll, Twentieth-Century Analytic Philosophy (Columbia University Press, 2000), p. 5: "[I]t is difficult to give a precise definition of 'analytic philosophy' since it is not so much a specific doctrine as a loose concatenation of approaches to problems." Also, see Stroll (2000), p. 7: "I think Sluga is right in saying 'it may be hopeless to try to determine the essence of analytic philosophy.' Nearly every proposed definition has been challenged by some scholar. [...] [W]e are dealing with a family resemblance concept."
^See Hans-Johann Glock, What Is Analytic Philosophy (Cambridge University Press, 2008), p. 205: "The answer to the title question, then, is that analytic philosophy is a tradition held together both by ties of mutual influence and by family resemblances."
^sacrifice. [17] Philoneos’ concubine went along for the sacrifice. When they were in Peiraieus, Philoneos sacrificed, of course. And when he had completed the sacrifice, the female wondered how to administer the drug to them, before or after dinner. And as she considered the matter she concluded that after dinner was better; she was also acting on the instructions of this Klytaimestra, my brother’s mother. [18] The full account of the dinner would be too longwinded for me to tell and you to hear. I shall try to give as brief an account as I can of the rest, of how the poison was administered. After dinner, naturally, since one was sacrificing to Zeus of Possessions and entertaining the other, and one was about to go on a voyage and was dining with a close friend, they made a libation and offered incense for their future. [19] And while Philoneos’ concubine was pouring the libation for them – as they offered prayers which would never be fulfilled, gentlemen – she poured in the poison. Thinking she was being clever, she gave more to Philoneos in the belief perhaps that if she gave him more she would win more affection from him – she had no idea that she was my stepmother’s dupe until disaster struck – while she poured less in our father’s drink. [20] They for their part after pouring their libations took their final drink, holding in their hands their own killer. Philoneos died at once on the spot; our father was afflicted with a sickness from which he died after twenty days. For this the assistant who carried out the act has the reward she deserved, though she was not to blame – she was put on the wheel and then handed over to the public executioner; the guilty party, the one who planned it, will soon have hers, if you and the gods will it. [21] Note how much more just my plea is than my brother’s. I urge you to avenge the dead man, who is the victim of an irreparable wrong. For the dead man my brother will offer no request, though he deserves your pity and support and vengeance for having his life taken in a godless and inglorious manner before his time by the last people who should have done this. [22] His plea will be for the murderess, a plea which is unprincipled, unholy, which deserves neither fulfilment nor attention either from the gods or from you; he will seek with his plea (to induce you not to convict her for her crimes) though she could not induce herself not to devise them.* But you must give your support not to those who kill but to the victims of deliberate. Trials from Classical Athens. Routledge. 2002-09-11: 47–48. ISBN 978-0-203-13047-6.
