你们给我一个有效论点的定义。
这完全排除了有效论点的可能。
这是有效论点，但是这不会说服你。
It's a valid argument but it won't ever going to persuade you.
大家都明白为什么这是有效论点了吧？
这是演绎有效论点的例子。
如果是有效论点才会完好，他有真前提。
It's only sound if it's a valid argument and it has true premises.
这是个有效论点，对吗？
我们知道什么呢？这是个有效论点，不是吗？
一个有效论点可能,前提都为假。
So you could have a valid argument in which the premises are all false.
这是个有效论点。
这是个演绎的有效论点，保留了真理，所以非常有用。
This is a deductively valid argument and its truth preserving and therefore it is very, very useful.
我说实际上发现那是有效论点，结论为假，可能很重要。
And I am saying actually the discovery that the valid argument is that the conclusion in which is false can be hugely important.
一旦你有一个有效论点，你可以加任何东西，他依然有效。
Once you have got an valid argument you can add anything you like and it will still be valid.
如果我们看到有效论点的结论为假，你们知道什么？有一点长。
So if we see the conclusion of a valid argument is false what do you know? A little bit longer.
实际上一个有效论点没有真前提和真结论，什么是有效论点呢？
Actually a valid argument doesn't have true premises and true conclusion what is a valid argument?
关于有效论点的一件很有意思的事，就像你们看到他们可能有错误的结论。
One of the interesting things about valid arguments as you'll see is that they can have false conclusion.
只要你们明白,只要停止思考有效论点有,真前提和真结论，你们就明白了。
And as soon as you understand that and as soon as you stop thinking of a valid argument having true premises and true conclusion you will see what's going on here.
对，所以如果论点有效，一个演绎的有效论点中结论是假的，你就知道前提中有一项是假的。
That's right. So if you have a valid argument a deductively valid argument in which the conclusion is false then you know one of the premises must be false.
所以你们看到这不是有效论点，因为前提，没关系，前提有多真，完全与结论无关，不是吗？
So you see that isn't a valid argument the reason because is that the premise-it doesn't matter how true the premise is, it's completely irrelevant to the conclusion isn't it?
但是如果我们一起放出这个，作为有效论点，我们知道的就为假，所以我们知道两者中的一个为假。
But if we put this together for a valid argument we get that is known to be false, so we know either one of these got to be false.
快速谈话的谬论，谬论的清单是供你们娱乐的，这里有个谬论，演绎的有效论点，有谬论看起来像。
So the fallacy of fast talking, and the list of fallacies are down there just for you amusement Okay here's a fallacy, well deductively valid argument and here's a fallacy that looks like it.
如果我们可以展示有效论点的结论-，举手，如果我们可以展示，有效论点的结论为假，我们知道什么？
If we can show the conclusion of a valid argument - put your hand up-if we can show the conclusion of a valid argument is false what do we know?
如果你否认结论，把所以拿掉，那么，如果你否认结论，这就不一致了，不是吗？这显示这是一个有效论点。
So if you negate that conclusion and took away the therefore, if you negated that conclusion the set would be inconsistent wouldn't it? And that shows you that that's a valid argument.
现在唯一重要的是你们要理解，什么事演绎的有效论点，也就是真理保留，如果前提是真的，结论必定是真的。
The only that that is important now is that you understand what a deductively valid argument is. That it is truth preserving, if the premises are true then the conclusion must be true.
好，给你们另一个测试，这是有效性的测试，另一个是有效论点中，如果且仅如果这是不一致的反例。
Okay I gave you another test. That was one test of validity and another test I gave you was in the argument is valid if and only is it's counterexample set is inconsistent.
所以我们有一个演绎的有效论点,但是这不是演绎有效的,实际上我们模态逻辑有很多要讲的,然后我们再讲道义逻辑。
So again we have a deductively valid argument but it's not deductively valid in actually we're a lot further on in modal logical then we are in deontic logic.
在很大程度上，格里森反对顶级群落和生物群系的论点用来反驳生态系统同样很有效。
Gleason's arguments against climax and biome are largely valid against ecosystems as well.
本文对“句内后照应单向性”论点的有效性提出质疑。
This paper questions the validity of the claim that intra-sentential cataphoric reference is unidirectional.
本文对“句内后照应单向性”这一论点的有效性提出质疑。
This paper questions the validity of the claim that "intra-sentential cataphoric reference is unidirectional".
本文对“句内后照应单向性”这一论点的有效性提出质疑。
This paper questions the validity of the claim that "intra-sentential cataphoric reference is unidirectional".
应用推荐