쉐도잉 연습: Turing & The Halting Problem - Computerphile - 영상으로 영어 말하기 배우기
레슨 만드는 중...
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Today we're going to be talking about a problem in logic, and how in solving that problem,
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Alan Turing almost inadvertently invented the modern digital computer.
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So we start back at the beginning of the 20th century, where mathematicians had posed this problem.
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- Thank you.
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In logic, we're interested in finding, do these premises entail this conclusion?
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So premises are the bits you start off with in an argument.
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They are the bits you know at the beginning or your assumptions.
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And the conclusion is the bit you want to establish, the bit that you reason to with your argument.
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And we want to know, is there a test that will tell us, yes, for sure, these premises do or don't entail this conclusion?
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Is there an automatic way of finding out whether they do or whether they don't. So that's the problem.
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It's called the decision problem.
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and mathematicians wanted to find out Is there an answer to the decision problem for first order logic?
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That's the kind of logic you learn in philosophy or mathematics at university.
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So lots of mathematicians were trying to work out, is first order logic decidable?
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That is, can we automatically test whether the premises entail the conclusion?
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Alan Shuring was one of the first to discover that first order logic isn't decidable.
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I To prove this, It's really difficult conceptually,
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because you have to be able to show no possible program can give you the answer.
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But how do you do that?
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How do you show something about every possible program?
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You can't run through every program one by one.
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But Turing came up with a brilliant solution.
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Yeah.
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His idea goes something like this.
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Suppose we have a program and let's just draw it as a black box.
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It's going to take some inputs, and it's going to give us some outputs.
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our program is going to solve some problem.
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a problem like, do the premises entail the conclusion?
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We ask it a question and it will give us an answer: yes, or no?
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Now here's another question we can ask: Thank you.
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Let's look at all of those possible programs.
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And we're just thinking of them as black boxes at the moment.
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We might want to know, is this program Given a certain input, gonna give us an answer.
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Or is it going to trundle on forever and never give us an answer?
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That is, is it going to halt or is it not going to halt eventually?
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So think about your computer running.
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You want it to give you an answer.
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And whether it's a good answer or a bad answer, it's better than no answer.
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No answer would mean the computer trundles round forever and ever in a loop.
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And you would just never know whether it's going to finish today, tomorrow or never.
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So halting is good.
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So there's another question we can ask: Given some program and some inputs, will it ever halt?
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Now it turns out that our logical problem Do these premises entail this conclusion?
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is very similar to this halting problem.
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In fact, if we can solve the logical problem, then we can solve the halting problem.
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Will this program halt on this input?
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So the clever part of Turing's proof is to show that it's impossible for any machine, however clever it is, to solve the halting problem.
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That is to tell us whether a given machine with a given input will halt or not.
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And here's how we did it.
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Let's suppose we've got a machine or a program that solves the problem for us it solves the holding problem.
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Don't worry about how it works, let's just think of it as a black box, taking a description of a machine and an input, and giving us an answer.
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Yes it will halt or no it won't halt.
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Just suppose that's possible.
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Call that machine H for the halting problem.
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If you give me that machine, I can transform it into a different machine like this.
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I stick some extra bits on it so that If it gives me a yes answer, I make it loop forever without ever stopping.
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If it gives me a no answer on the other hand, it's gonna halt straight away.
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Let's call that big machine the whole thing.
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H plus.
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Now here's another question we can ask: what happens if I feed the whole machine into itself.
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So I'm going to put H plus Thank you in here and H + in here.
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So the question I'm now asking is, I'm feeding H + into itself.
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So I'm asking the question: Does H + halt?
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give an input H+.
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And here's where it all goes wrong.
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because If H + does halt, We get a yes answer.
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But then it loops forever, so it doesn't halt.
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On the other hand, if it doesn't halt, We get a no answer, but then it halts.
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So if it does halt, then it doesn't halt.
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But if it doesn't halt, then it does halt.
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Either way, we get a contradiction.
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It's a paradox.
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And what that shows is we started off assuming that we can solve the problem.
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we've ended up with a paradox.
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So our assumption was bad.
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It turns out there's no possible machine, no possible program that solves the halting problem.
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The really clever bit about Turing's idea is it doesn't matter what kind of program or machine it is.
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It doesn't matter whether it's An abstract algorithm, whether it's a real computer, a physical computer, it doesn't matter what it is.
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We've proved that no such program is possible.
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you Turing, as part of his argument, had to say a little bit about what's going on in these black boxes.
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And the idea is that every card represents an instruction in this Turing machine.
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이 영상의 핵심 어휘
영상에 나오는 익혀 둘 만한 단어 14개를 발음, 뜻과 함께 정리했습니다.
| 단어 | 발음 | 뜻 |
|---|---|---|
| hungry 형용사 | /ˈhʌŋ.ɡɹi/ | 배고프다, 굶주리다 |
| solve 동사 | /sɒlv/ | 해결하다 |
| conclusion 명사 | /kənˈkluːʒən/ | 종결 |
| loop 명사 | /luːp/ | 고리 |
| paradox 명사 | /ˈpæ.ɹəˌdɒks/ | 모순, 자가당착 |
| output 명사 | /ˈaʊtpʊt/ | 출력 |
| discover 동사 | /dɪˈskʌvə/ | 발견하다 |
| automatic 형용사 | /ˌɔː.təˈmæt.ɪk/ | 자동, 자동적 |
| mathematics 명사 | /mæθ(.ə)ˈmæt.ɪks/ | 수학 |
| transform 동사 | /tɹænsˈfɔɹm/ | 변형시키다, 변형하다 |
| algorithm 명사 | /ˈælɡəɹɪðm̩/ | 알고리즘, 알고리듬 |
| invent 동사 | /ɪnˈvɛnt/ | 발명하다 |
| mathematician 명사 | /ˌmæθ.(ə.)məˈtɪʃ.ən/ | 수학자 |
| contradiction 명사 | /ˌkɑːntɹəˈdɪkʃən/ | 모순 |
주의할 발음
화자는 doesn't, I'm, don't 같은 축약형과 약화된 형태를 25번 사용합니다. 들리는 대로 짧게 발음하세요.
- “th” 소리: mathematics /mæθ(.ə)ˈmæt.ɪks/, algorithm /ˈælɡəɹɪðm̩/, mathematician /ˌmæθ.(ə.)məˈtɪʃ.ən/
- “sh”와 “zh” 소리: conclusion /kənˈkluːʒən/, assumption /əˈsʌm(p).ʃ(ə)n/, establish /ɪˈstæb.lɪʃ/, instruction /ɪnˈstɹʌkʃən/, mathematician /ˌmæθ.(ə.)məˈtɪʃ.ən/
- 긴 단어 — 강세 위치에 주의: automatic /ˌɔː.təˈmæt.ɪk/, mathematics /mæθ(.ə)ˈmæt.ɪks/, mathematician /ˌmæθ.(ə.)məˈtɪʃ.ən/, decidable [dɪˈsaɪdəbəɫ], conceptually /kənˈsɛp.tjʊə.li/
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쉐도잉이란? 영어 실력을 빠르게 키우는 과학적 방법
쉐도잉(Shadowing)은 원래 전문 통역사 훈련을 위해 개발된 언어 학습 기법으로, 다언어 학자인 Dr. Alexander Arguelles에 의해 대중화된 방법입니다. 핵심 원리는 간단하지만 매우 강력합니다: 원어민의 영어를 들으면서 1~2초의 짧은 지연으로 즉시 소리 내어 따라 말하는 것——마치 '그림자(shadow)'처럼 화자를 따라가는 것입니다. 문법 공부나 수동적인 청취와 달리, 쉐도잉은 뇌와 입 근육이 동시에 실시간으로 영어를 처리하고 재현하도록 훈련합니다. 연구에 따르면 이 방법은 발음 정확도, 억양, 리듬, 연음, 청취력, 말하기 유창성을 크게 향상시킵니다. IELTS 스피킹 준비와 자연스러운 영어 소통을 원하는 분들에게 특히 효과적입니다.








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