×

Utilizziamo i cookies per contribuire a migliorare LingQ. Visitando il sito, acconsenti alla nostra politica dei cookie.


image

Crash Course 2: Philosophy., 02b. How to Argue - Philosophical Reasoning. Part 2/2.

02b. How to Argue - Philosophical Reasoning. Part 2/2.

So, here's a boiled-down version of a good deductive argument:

● Premise 1: All humans are mortal.

● Premise 2: Socrates is a human.

● Conclusion: Socrates is mortal.

This kind of reasoning, where one fact leads to another, is called entailment.

Once we know that all humans are mortal, and that Socrates is a human, those facts entail that Socrates is mortal. Deduction begins with the general – in this case, what we know about human mortality – and reasons down to the specific – Socrates in particular.

What's great about deductive arguments is that the truth of the premises must lead to the truth of the conclusion.

When this happens, we say that the argument is valid – there's just no way for the conclusion to be false if the premises are true.

Now check out this argument: All humans are mortal. Socrates is a human.

Therefore, Socrates was Plato's teacher.

That argument is invalid, because nothing about human mortality can prove that Socrates was Plato's teacher. As you might have noticed, there are plenty of mortal humans who never taught Plato.

What's interesting, though, is that this argument does happen to have a true conclusion, which leads us to another issue. And that is: Validity is not the same as truth.

All ‘valid' really means is that if the premises are true, then your conclusion can't be false. But that doesn't mean that your premises prove your conclusion to be correct. Like, in the case of whether Socrates was Plato's teacher, the premises are true, and the conclusion is true, but the argument is still not valid -- because the premises don't in any way prove the conclusion. It just happens to be true.

So, if your premises don't guarantee the truth of your conclusion, then you can end up with some really crappy arguments. Like this one:

- All cats are mammals

- I'm a mammal

- Therefore, I'm a cat

As much as part of me would like to be my cat, this is invalid because the conclusion doesn't entail from the premises…at all.

I mean, all cats are mammals, but all mammals aren't cats. Which means there are such things as non-cat mammals, which I am just one example of. And it probably goes without saying, but you can have a perfectly valid argument and still have a false conclusion, if any of your premises are false. For example:

- All humans have tails

- My brother John is a human

- Therefore, John Green has a tail!

The argument is totally valid! – Because the premises entail the conclusion! The reasoning totally stands up! It's just that one of the premises is flawed.

Since I'm reasonably certain that John doesn't have a tail -- I've seen him in a bathing suit -- this argument is not deductively sound. And a deductively sound argument is one that's free of formal flaws or defects.

It's an argument whose premises are all true, and that's valid, which means its conclusion is guaranteed to be true.

So, sound arguments should always be your goal. The reason that deduction is prized by philosophers -- and lots of other important kinds of thinkers -- is that it's the only kind of argument that can give you a real certainty.

But it's limited, because it only works if you're starting with known, true premises, which are hard to come by. And for what it's worth, deductive truths are usually pretty obvious. They don't tend to lead us to startlingly new information, like the fact that I'm not a cat, or that John doesn't have a tail.

So instead of starting with premises that are already certain, like deduction does, you're gonna have to know how to determine the truth of, and your confidence in, your premises. Which means you're going to have to acquaint yourself with the other species of arguments, which we're gonna do next time.

But today, we talked about the value of reason, the structure of arguments, and we took a close look at one kind of argument: deductive reasoning.

This episode of Crash Course Philosophy is made possible by Squarespace. Squarespace is a way to create a website, blog or online store for you and your ideas. Squarespace features a user-friendly interface, custom templates and 24/7 customer support. Try Squarespace at squarespace.com/crashcourse for a special offer.

Crash Course Philosophy is produced in association with PBS Digital Studios. You can head over to their channel to check out amazing shows like The Art Assignment, The Chatterbox, and Blank on Blank.

This episode of Crash Course was filmed in the Doctor Cheryl C. Kinney Crash Course Studio with the help of all of these amazing people and our Graphics Team is Thought Cafe.

02b. How to Argue - Philosophical Reasoning. Part 2/2. 02b. Wie man argumentiert - Philosophische Argumentation. Teil 2/2. 02b. Cómo argumentar - Razonamiento filosófico. Parte 2/2. 02b. Hoe te argumenteren - Filosofisch redeneren. Deel 2/2. 02b. Jak argumentować - rozumowanie filozoficzne. Część 2/2. 02b. Como Argumentar - Raciocínio Filosófico. Parte 2/2. 02b. Как аргументировать - Философские рассуждения. Часть 2/2. 02b. Nasıl Tartışılır - Felsefi Akıl Yürütme. Bölüm 2/2. 02b. Як сперечатися - філософські міркування. Частина 2/2. 02b. 如何辩论 - 哲学推理。第 2/2 部分。

So, here’s a boiled-down version of a good deductive argument: Отже, ось скорочена версія хорошого дедуктивного аргументу:

● Premise 1: All humans are mortal. ● 前提1:所有人都会死。

● Premise 2: Socrates is a human.

● Conclusion: Socrates is mortal.

This kind of reasoning, where one fact leads to another, is called entailment. Este tipo de razonamiento, en el que un hecho lleva a otro, se denomina vinculación. Такий тип міркувань, коли один факт призводить до іншого, називається наслідком.

Once we know that all humans are mortal, and that Socrates is a human, those facts entail that Socrates is mortal. Як тільки ми знаємо, що всі люди смертні, і що Сократ - людина, з цих фактів випливає, що і Сократ смертний. Deduction begins with the general – in this case, what we know about human mortality – and reasons down to the specific – Socrates in particular. Дедукція починається із загального - в даному випадку, з того, що ми знаємо про людську смертність - і приводить до конкретного - зокрема, до Сократа.

What’s great about deductive arguments is that the truth of the premises must lead to the truth of the conclusion. Що чудово в дедуктивних аргументах, так це те, що істинність передумов повинна привести до істинності висновку. 演绎论证的伟大之处在于前提的真实性必然导致结论的真实性。

When this happens, we say that the argument is valid – there’s just no way for the conclusion to be false if the premises are true. Коли таке трапляється, ми говоримо, що аргумент є обґрунтованим - просто не може бути, щоб висновок був хибним, якщо передумови є істинними.

Now check out this argument: All humans are mortal. 现在来看看这个论点:所有人都会死。 Socrates is a human. 苏格拉底是人。

Therefore, Socrates was Plato’s teacher. 因此,苏格拉底是柏拉图的老师。

That argument is invalid, because nothing about human mortality can prove that Socrates was Plato’s teacher. Цей аргумент є недійсним, оскільки ніщо з того, що стосується людської смертності, не може довести, що Сократ був учителем Платона. 该论点无效,因为没有任何关于人类死亡率的证据可以证明苏格拉底是柏拉图的老师。 As you might have noticed, there are plenty of mortal humans who never taught Plato. Як ви могли помітити, є багато смертних людей, які ніколи не вчили Платона.

What’s interesting, though, is that this argument does happen to have a true conclusion, which leads us to another issue. Lo interesante, sin embargo, es que este argumento tiene una conclusión verdadera, lo que nos lleva a otra cuestión. Цікаво, однак, що цей аргумент має правдивий висновок, який підводить нас до іншого питання. 但有趣的是,这个论点确实有一个正确的结论,这引出了另一个问题。 And that is: Validity is not the same as truth. Y es que: Validez no es lo mismo que verdad. І це так: Достовірність - це не те саме, що істина.

All ‘valid' really means is that if the premises are true, then your conclusion can’t be false. Lo único que significa "válido" es que si las premisas son ciertas, la conclusión no puede ser falsa. Слово "достовірний" насправді означає, що якщо передумови істинні, то ваш висновок не може бути хибним. But that doesn’t mean that your premises prove your conclusion to be correct. Pero eso no significa que tus premisas demuestren que tu conclusión es correcta. Але це не означає, що ваші передумови доводять правильність вашого висновку. Like, in the case of whether Socrates was Plato’s teacher, the premises are true, and the conclusion is true, but the argument is still not valid -- because the premises don’t in any way prove the conclusion. It just happens to be true. Так сталося, що це правда. 这恰好是事实。

So, if your premises don’t guarantee the truth of your conclusion, then you can end up with some really crappy arguments. Отже, якщо ваші передумови не гарантують істинності вашого висновку, то в результаті ви можете отримати дійсно паскудні аргументи. 因此,如果你的前提不能保证你的结论的真实性,那么你最终会得到一些非常糟糕的论点。 Like this one:

- All cats are mammals

- I’m a mammal

- Therefore, I’m a cat

As much as part of me would like to be my cat, this is invalid because the conclusion doesn’t entail from the premises…at all. Por mucho que una parte de mí quisiera ser mi gato, esto no es válido porque la conclusión no se deduce de las premisas... en absoluto. Як би частина мене не хотіла бути моїм котом, це невірно, тому що висновок не випливає з передумов... взагалі.

I mean, all cats are mammals, but all mammals aren’t cats. Which means there are such things as non-cat mammals, which I am just one example of. Це означає, що існують ссавці, які не є котами, і я - лише один із прикладів. 这意味着存在非猫类哺乳动物,我只是其中一个例子。 And it probably goes without saying, but you can have a perfectly valid argument and still have a false conclusion, if any of your premises are false. Y probablemente no haga falta decirlo, pero puedes tener un argumento perfectamente válido y aún así tener una conclusión falsa, si alguna de tus premisas es falsa. For example:

- All humans have tails - 所有人类都有尾巴

- My brother John is a human

- Therefore, John Green has a tail!

The argument is totally valid! – Because the premises entail the conclusion! The reasoning totally stands up! Аргументація цілком виправдана! It’s just that one of the premises is flawed. 只是其中一个前提有缺陷。

Since I’m reasonably certain that John doesn’t have a tail -- I’ve seen him in a bathing suit -- this argument is not deductively sound. Оскільки я цілком впевнений, що у Джона немає хвоста - я бачив його в купальному костюмі - цей аргумент не є дедуктивно обґрунтованим. And a deductively sound argument is one that’s free of formal flaws or defects. А дедуктивно обґрунтований аргумент - це аргумент, вільний від формальних недоліків або дефектів.

It’s an argument whose premises are all true, and that’s valid, which means its conclusion is guaranteed to be true. 它是一个前提都为真的论证,是有效的,这意味着它的结论保证是正确的。

So, sound arguments should always be your goal. Отже, ви завжди повинні мати на меті обґрунтовані аргументи. The reason that deduction is prized by philosophers -- and lots of other important kinds of thinkers -- is that it’s the only kind of argument that can give you a real certainty.

But it’s limited, because it only works if you’re starting with known, true premises, which are hard to come by. Pero es limitado, porque sólo funciona si se parte de premisas conocidas y verdaderas, que son difíciles de conseguir. Але він обмежений, тому що працює лише тоді, коли ви починаєте з відомих, істинних передумов, які важко отримати. And for what it’s worth, deductive truths are usually pretty obvious. Y si sirve de algo, las verdades deductivas suelen ser bastante obvias. І якщо вже на те пішло, дедуктивні істини, як правило, досить очевидні. 不管怎样,演绎真理通常都是非常明显的。 They don’t tend to lead us to startlingly new information, like the fact that I’m not a cat, or that John doesn’t have a tail. Вони не мають тенденції приводити нас до приголомшливо нової інформації, як, наприклад, той факт, що я не кіт, або що у Джона немає хвоста.

So instead of starting with premises that are already certain, like deduction does, you’re gonna have to know how to determine the truth of, and your confidence in, your premises. Así que en lugar de empezar con premisas que ya son ciertas, como hace la deducción, tendrás que saber cómo determinar la verdad de tus premisas y tu confianza en ellas. Тож замість того, щоб починати з передумов, які вже визначені, як це робить дедукція, вам потрібно знати, як визначити істинність ваших передумов і вашу впевненість у них. Which means you’re going to have to acquaint yourself with the other species of arguments, which we’re gonna do next time. Це означає, що вам доведеться познайомитися з іншими видами аргументів, що ми і зробимо наступного разу. 这意味着你必须熟悉其他类型的论点,我们下次将会讨论。

But today, we talked about the value of reason, the structure of arguments, and we took a close look at one kind of argument: deductive reasoning.

This episode of Crash Course Philosophy is made possible by Squarespace. Squarespace is a way to create a website, blog or online store for you and your ideas. Squarespace features a user-friendly interface, custom templates and 24/7 customer support. Squarespace 具有用户友好的界面、自定义模板和全天候客户支持。 Try Squarespace at squarespace.com/crashcourse for a special offer. 请访问 squarespace.com/crashcourse 尝试 Squarespace,享受特别优惠。

Crash Course Philosophy is produced in association with PBS Digital Studios. 《速成哲学课程》是与 PBS 数字工作室联合制作的。 You can head over to their channel to check out amazing shows like The Art Assignment, The Chatterbox, and Blank on Blank.

This episode of Crash Course was filmed in the Doctor Cheryl C. Kinney Crash Course Studio with the help of all of these amazing people and our Graphics Team is Thought Cafe. 本期《速成课程》是在 Cheryl C. Kinney 博士速成课程工作室拍摄的,得到了所有这些出色的人的帮助,我们的图形团队是 Thought Cafe。