Cyc 或类似知识库项目的可表达性有限制吗？
是否有某些概念无法表达？有没有一个项目可以表达任何概念？
我还不明白 Cyc 的语法，但这里有一个例子：（
(forAll ?CAT
(implies
(isa ?CAT DomesticCat)
(eatsWillingly ?CAT Meat)))
我认为它的意思是：家猫就是猫，猫愿意吃肉！）
所以，假设回答这个问题的人完全了解 Cyc 的语言，我的对他来说，问题是“什么概念不能用 cyc 表达”。
例如这个概念：
“一个人怎么会跌倒这么远而没有意识到”。
有没有一种知识表示语言能够完整地表示这个陈述？
但我真正的问题是……是否有任何知识表示语言可以表达任何概念。据我所知，还没有一个项目（无论是 cyc、wordnet、prolog 还是其他任何项目）可以代表每种概念。但我对 Cyc 的了解还不够深，无法肯定地说。
What are the limits to expressibility, in Cyc or similar knowledge-base projects.
Are there certain concepts that can't be expressed? Is there any project that can express any concept?
I don't understand Cyc's syntax yet, but here is one example:
(forAll ?CAT
(implies
(isa ?CAT DomesticCat)
(eatsWillingly ?CAT Meat)))
(I think what it means, is: domestic cats are cats, and cats willingly eat meat!)
So, assuming the person answering this question knew Cyc's language fully, my question to him, would be "What concepts can't be expressed in cyc".
For example this concept:
"How can someone fall so far, without realising it".
Is there any knowledge-representation language that can fully represent this statement?
But my real question is... is there any knowledge-representation language, that can express any concept. As far as I'm aware, there is no project yet (whether cyc, wordnet, prolog, or anything else) that can represent every kind of concept. But I don't know Cyc well enough to say that for sure.
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知识是一个多方面的主题，我记得有一句古老的格言，就像“要了解身体，你需要身体来推理”。
这意味着我们的很多知识无法用逻辑术语来表达，而是需要跨学科的方法。
如果您想接触自然语言领域的实用知识，您可以学习（即阅读文档、安装和使用）尝试。这是一种“受控英语”语言，您可以通过一些推理来学习。
作为知识表示媒介而积极开发的受限语言，使其成为一种非常有趣的技术。
Knowledge it's a multi faceted theme, and an old maxim I recall it's something like 'to have knowledge of a body, you need a body to reason about'.
What this means it's that so much of our knowledge isn't expressible in logical terms, but require an interdisciplinary approach.
If you want to approach with something of practical in the natural language domain, you could study (i.e. read docs, install and play with) Attempto. It's a 'controlled English' language, with some reasoner you can study.
The restricted language, actively developed as a knowledge representation medium, make it a very interesting technology to use.
上面的说法实际上只是意味着“所有家猫都愿意吃肉”。该变量只是一个变量（尽管有它的名字）。
至于 CycL 的表达能力，原则上，几乎任何东西都是可表达的，因为它是一种 n 阶语言（但局部很少超过二阶）并且完全可扩展。人们总是可以创建必要的词汇，并为其“注入”必要的语义，甚至可以表达“一个人怎么会跌倒这么远，却没有意识到这一点？”这一问题。也就是说，Cyc 项目的基础是基于这些表示的推理。为此，一切可能都是可以的，但并非一切都是有益的。因此，建立一个包含足够词汇和规则的知识库来推理公众人物失宠（例如）可能需要一段时间，并且涉及的不仅仅是表达单个陈述。
另外，值得注意的是，CycL 的目的是作为一种能够代表我们进行语音的概念的语言，但不一定以类似于我们谈论它们的方式。那么“一个人怎么会跌倒这么远而不自知呢？”可能不会在 CycL 中以其所有隐喻包袱来表示。人们很可能会使用涉及社会位置（或空间，如果问题是字面意思的话）的词汇，以及涉及个人对其自身社会（空间）状况的意识的词汇。这可以在 CycL 中完成。此外，Cyc 可以为此类问题提供令人满意的解释性答案（前提是有正确的规则等）。
The statement above actually only means "all domestic cats willingly eat meat". The variable is just a variable (despite its name).
As for the expressiveness of CycL, in principle, just about anything is expressible, seeing as it is an nth order language (but locally rarely exceeds second order) and fully extensible. One can always create the necessary vocabulary and "imbue" it with the requisite semantics to express even the question "How can someone fall so far, without realising it?". That said, the bread and butter of the Cyc project is inference based on these representation. To this end, everything may be permissible, but not all things are beneficial. So, building out a knowledge base with enough vocabulary and rules to reason about public figures falling from grace (for example) might take a while and involve considerably more than just representing that single statement.
Also, it is worth noting that CycL is intended as a language capable of representing the concepts with which we engage in speech, but not necessarily in a manner analogous to the way we speak about them. So "How can someone fall so far, without realising it?" would likely not be represented in CycL with all of its metaphorical baggage. One would most likely use vocabulary involving social position (or spatial, if the question is meant literally) and vocabulary involving an individual's awareness of their own social (spatial) situation. This could be accomplished in CycL. Furthermore, Cyc could provide a satisfactory, explanatory answer to such a question (provided the right rules, etc., are in place).