could have doneは“したかもしれない”
can/couldの推測用法について詳しく見ていきます。
English Grammar SecretsからCan have / Could haveのページを引用しますが、なぜか変な順序で説明しているので分かりやすいように順番を入れ替えてあります。
１．can have done/can't have doneについて
Can have / Could have‐English Grammar Secrets
We can also use 'can have' to speculate about what has happened but only in questions and negative sentences and with words such as 'hardly', 'never' and 'only'.
can have doneは基本的に疑問文・否定文で使われる。
２．could have doneについて
could have doneの意味は過去への推測と反実仮想の２つがあります。
まずは過去への推測。
We can use 'could have' to speculate about what has happened. (We can also use 'may have' or 'might have' in these situations.)
- She could have taken the earlier train.
- Simon could have told her.
- They could have overheard what we said.
「過去の出来事に対する推測」
この説明だとcapabilityとは言っていないので、文字通り取れば「〜したかもしれない」という意味はなるけれども「〜できたかもしれない」という意味にはならないことになります。
さてもう一つの反実仮想。
これは、「〜したかもしれないのに（実際はしなかった）」「〜できたのに（実際はしなかった）」の２つの意味でとることができます。
We can also use 'could have' to speculate about something that didn't happen.
- You could have broken your neck, jumping out the window like that.
- He could have hurt somebody, throwing a bottle out of the window like that.
- I could have done well in my exam if I'd worked harder.
「実際には起きなかった事柄に対しての推測」
We can use 'could have' to talk about something somebody was capable of doing but didn't do.
- I could have gone to Oxford University but I preferred Harvard.
- She could have married him but she didn't want to.
- They could have bought a house here 20 years ago but chose not to.
Often, there is a sense of criticism.
- You could have phoned me to let me know.
- They could have helped me instead of just sitting there.
- I could have done more to help you. Sorry.
「出来たのに実際にはしなかった事柄に対しての推測・非難」
反実仮想の場合はなぜか“能力”について言及できます。
また、これ以外にも単なる例え話をしている場合もあります。
これは一見すると反実仮想ですが、実際は事実の推測をしていることになります。。
例えば以下の例だと、
- Colossal sea monster of Dorset that could have 'eaten T Rex for breakfast'‐dailymail.co
‘Its jaw was designed to deliver a bite so powerful that it could have ripped a car in half with no problem.
‘It could have taken a human in one gulp. In fact, something like a T Rex would have been breakfast for a beast like this.
実際には起こりえないことを話していますが、それじゃあ話者が言いたいのは「でも実際には違った」ということなのかというとそうではありません。
この辺は、“仮定法”をrealかunrealかで２分する方法の限界と言えます。
最後の例は、実現しえない仮定の場合には敢えてMixed Conditionalにしたりせずに“仮定法過去完了”のままにする、ということの説明です。
You can also use 'could have' to talk about possible present situations that have not happened.
- I could have been earning a lot as an accountant but the work was just too boring.
- He could have been Prime Minister now but he got involved in a big financial scandal.
- They could have been the market leaders now if they had taken his advice.
「could have doneで反実仮想だけども今の状況について表現できる」
３．couldn't have doneについて
couldn't have doneはcould have doneの否定形ですので、同じように過去への推測と反実仮想の２つがあります。
We can use 'couldn't have' to talk about something we were not capable of doing.
- I couldn't have managed without you.
- I couldn't have got the job. He was always going to appoint his nephew.
- I couldn't have enjoyed myself more. Thank you for a lovely day.
ここでいう「する能力がなかった事柄」という説明は必ずしも全体像を捉えていないように思います。
いずれにしても、この説明に従えばcould have doneが反実仮想ではなく事実の推測である限り、“する能力があった”という意味は出てこないことになります。
キューティーブロンド("Legally Blonde")‐あの映画のセリフを極めてやる！
- I just don't think that Brooke could've done this.(ブルックに殺せたはずがないわ。）
※Brookeの無罪を信じるエルの台詞。会話の流れで、done this は殺人を意味している。直訳するとこれが出来たのはブルックだけだとは思わない。で、つまり「ブルックにできたはずがないと思う」 ⇒I just think that Brooke couldn't have done this. といいたいのだけれど、英語ではthat以下を肯定文にするのが一般的なので、「ブルックができたと思わない」というのがナチュラル☆ またcould have done はとても感情的に可能性を表せるので便利！
ということは、上の例であれば「殺せたはずがない」という意味ではなく「殺したはずがない」になるべきです。
隠れ家的英語教室‐週刊ＳＴ ＯＮＬＩＮＥ
続けて第８パラグラフ。なぜアイビンス博士が事件の容疑者として名前が挙がったのかを見ていきましょう。要約すると「アイビンス博士は炭疽菌を簡単に手に入れられる地位にあり、彼の研究所は炭疽菌テロによりお金と資源の面で利益を得た（benefited）。彼は炭疽菌ワクチンに関して２つの特許（patents）を持っており、（炭疽菌事件により）ワクチンが必要になったことで、お金を稼ぐことができたはずだ（could have made money）」。こう考えると事件の容疑者になったのも納得です。
また、こちらも「稼ぐことができたはずだ」ではなく「稼いだかもしれない」となるべきでしょう。
しかしながら、
could/might have‐WordReference.com
- You can hurt his feelings by what you said. [You are able, you have the power, to hurt his feelings.]
- You may hurt his feelings by what you said. [It is possible for you to hurt his feelings.]
- That can hurt his feelings. [That has the power to hurt his feelings.]
- That may hurt his feelings. [It is possible for that to hurt his feelings.]
Could is a form of can, and might a form of may, so the same nuance applies:
- What you said could have hurt his feelings. [Your words had the power (or would have had the power) to hurt his feelings.]
- What you said might have hurt his feelings. [It was possible (or it would have been possible) for your words to have hurt his feelings.]
のように、反実仮想ではないcould have doneに“する能力があった”という意味を認める声もあるようなので、はっきりとしたことはいえません。
would have been able to
一般的に、could have doneはwould have been able to doに置き換えられると言われています。
この説明は前述の疑問をより複雑にしていますが、少なくとも推測と可能の２つの意味を合わせた「できたかもしれない」という言い方をするためにはwould have been able to doという表現をすればいいことだけは分かります。
以下の例は同じ内容ですが、
T. rex 'would outrun footballer'‐BBC
- Tyrannosaurus rex would have been able to outrun a footballer, according to computer models used to estimate running speeds of dinosaurs.
のように、“would have been able to do”の形を使ったり、
T. Rex Could Outrun Humans‐nzherald.co.nz
- Turns out, T. rex could have outrun some of the buffest athletes.
というようにcould have doneの形を使うこともできます。
こうした用法においても、純粋な過去への推測、現実には起きなかった推測、いわゆる反実仮想というように、話者の言いたいことがちょっとずつ異なってきます。
どの意味なのかは完全に文脈によりますし、どのような意味があるのかさえ知っていれば分類する必要すらありません。
ここでは説明のためにあえて分類してみます。
１．推測
Piedras Marcadas: Pueblo's clash with Coronado uncovered‐The Santa Fe New Mexican.com
Spanish documents say Moho was on high ground, affording it some natural defense, while Piedras Marcadas is so low and near the river that the well diggers would have been able to reach the shallow groundwater table without the walls collapsing around them, Flint said.
「掘ることができただろう」という過去への推測。
Adapting to climate change may have been easier 13,500yrs ago‐India Talkies
“Five hundred years, a thousand years ago people would have been able to respond to changes in distribution and abundance whether driven by natural cycles or by changes in the climate or weather,” said Gerlach. “People are no longer as flexible because they live in permanent villages, so they can’t respond appropriately.”
「変化に対応できただろう」という過去への推測。
２．反実仮想かつ推測
Usain Bolt would have been outrun by our ancestors, claims anthropologist‐The Telegraph
However, because of the quirk of her physiology, with a much shorter lower arm, he believes a Neanderthal woman would have been able to “slam him to the table without a problem”.
「腕相撲ならネアンデルタール人の女性が勝つだろう」という推測。
Alright, I know what you're thinking, if a child like Goku who didn't even know how to fly and use other ki attacks other than Kamehameha wave was able to beat them by himself, how much more Vegeta and Nappa when they arrived?
Well, remember that the Red Ribbon army made all those androids. So assuming Goku died from that fall when he was a baby, they would have been able to make so much more androids with Dr. Gero's genius. 20 androids if I'm not mistaken. Because that's like 10+ years of more android making and technology without Goku ruining it.
「悟空が幼いころに死んでいたら、レッドリボン軍は人造人間をもっとたくさん造ることができただろう」という推測。
３．反実仮想
Players That Would Have Been Free Agents After 2010‐MLB Trade Rumors
- Nick Swisher: The Yanks owe Swisher $9MM for 2011, then have to decide between a $10MM salary or a $1MM buyout for 2012. He probably would have been able to find more than that as a free agent.
「複数年契約せずにＦＡできていたらもっと稼げていただろうに」という推測。
Experts Say Tsunami Warning System Would Have Saved Lives‐VOANews.com
"Had they had tide gauges installed, many of these people that were farther away from the epicenter could have been saved because they would have been able to track the waves and tell the people along the coast area to move off the beach and give them an approximate time the waves were going to hit.
「津波を監視することができていただろうに」という推測。
could have been able to
could have doneだけだと「できた」という意味がなかなか出てこないので、be able toと合体したcould have been able toという形が登場します。
どうにも見慣れませんが、このパターンにおいても純粋な推測から反実仮想に至るグラデーションがあります。
１．推測
Meteorites may have kick-started life on Earth‐The Telegraph
"Up until now scientists have imagined that primitive life would not have been able to withstand this pummelling.
"But our analysis of the mineral told us that this ancient microbe could have been able to survive meteorite bombardment through a combination of living underground and reinvading the surface rock while it was still very hot.
「生き延びることができただろう」という過去への推測。
Ridge clue to Antarctic ice loss‐BBC
"We now know that there is relatively warm water beneath this floating ice," observed Dr Dutrieux, "so this warm water could have been able to melt the base of the ice shelf.
「溶かすことができただろう」という過去への推測。
Adjaran roots of the spy scandal‐Georgiatoday
Two Russian citizens of Armenian origin, Armen Gevorkyan and Ruben Shikoyan, the general manager and deputy of the Georgian branch of the Seybolt company, are also accused of espionage.
The firm specialized in naval transportation, which gives ground to the assumption that they could have been able to obtain information about military and double-purpose cargoes entering the Georgian ports of Batumi and Poti.
「入手できただろう」という過去への推測。
２．反実仮想かつ推測
Voters may need to show ID in future‐westernwheel.com
Returning councillors said requiring ID has never been considered in the past.
Newly elected Mayor Bill Robertson said he didn’t have any problems with how the vote went last week.
He said security and staff working on election day could have been able to recognize anyone who may have tried to vote twice.
「気付くことができただろう」という例え話。
Multiplicity of the Arts and the Health of a City‐Let's Save Michigan
And while Michigan's economy continues to struggle there are still amazing and offbeat ways to enrich our souls while enjoying our cities.
In the city of Detroit for instance this past weekend, without much effort a person could have been able to experience arts and culture that ranged from a home-grown hipster fair to world class art exhibits to avant-garde art house cinema.
「鑑賞することができただろう」という例え話。
Hitler's Aircraft Carrier Found Undersea‐Jetphotos.net
Perhaps modified JU-88's, or perhaps earlier in the war, He 111's, could have been able to use the carrier? These could have been capable of much more destruction than the JU-87.
「着艦できただろう」という推測。
３．反実仮想
The Alpha Magnetic Spectrometer Might Solve the Mysteries of the Universe‐Metrolic
In 1974 he made one of the greatest discoveries; a particle which could have been able to revolutionize the physics world. Unfortunately he spent too much time with the research that in the meantime a different laboratory got involved in the study, so the two had to split the Nobel Prize.
「根底から覆すことができただろう」という推測。
Uma Thurman Was Nearly Eowyn In The Lord Of The Rings!‐Filmonic
“Oh I truly wish I could’ve been able to take that plunge and maybe I should’ve,” she revealed. “But I just couldn’t at the time.”
「チャレンジできていたらな」という願望。
couldn't have been able to
否定形も同様です。
１．推測
Dee Jay Nelson‐Light Planet
At the time of the uprising of the Egyptian Army in the early hours of the morning of the 23rd of July 1952, King Farouk was in Alexandria. He left Egypt, for good, from the Ras-El-Tin Palace. It is practically impossible that the late King Farouk could have been able to take any thing from his impressive Egyptian Antiques collection with him on his departure. The collection was found complete and untouched in the Abdine Palace in Cairo. . . .
「持って行けたはずがない」という過去への推測。
William Herlong, Attorney at Law
I have even called upon an acoustics expert to prove that my client couldn't have been able to hear a crucial alarm.
「聴けたはずがない」という過去への推測。
２．反実仮想かつ推測
Transcript of Interview with Tommy Thompson‐Spychips.com
And if people would have said, you know, ten years ago, "What's an iPod?" nobody could have been able to explain it.
「説明できなかったはずだ」という過去への推測。
３．反実仮想
Taiwan’s Golden Horse Awards: Winners, Losers, Long Speeches, and Movies We Can’t Wait to See‐MTV IGGY
“I’d like to thank the people of Kaohsiung, no matter whether the government or the everyday citizens,” Dai said to the crowd. “We couldn’t have been able to finish it without their support.”
「達成できなかったはずだ」という推測。
could have doneにまつわるＱ＆Ａ
could have doneに関連した疑問で最も紛らわしいのが、can't have doneとcouldn't have doneにどのような違いがあるかという点です。
１．can't have done/couldn't have done‐WordReference.com
- She can't have done it.
I refuse to believe that she did it.
- She couldn't have done it.
It was not possible for her to have done it.
この説明は分かるような分からないような、という感じですね。
２．can't have 過去分詞とcouldn't have 過去分詞‐教えて！goo
can't have過去分詞のほうは、「（今考えて昔の）そう言うことはあり得ない」であり、
couldn't have過去分詞は、「（今考えて昔の）そう言うことはあり得ないだろう」のように多少推測の意味が強く出ます。
“多少推測の意味が強く出る”というか、もともと両方とも推測なので、その点で違いはないと思います。
３．助動詞「cannot have done / couldn't have done」の違いは何ですか？？？‐Yahoo!知恵袋
ベストアンサー
この両者がもっとも異にするのは網羅する「時間帯」です。
同様の考えは"can't have been" vs "couldn't have been"にもありますが、正しいかどうかは分かりません。
４．He can't/couldn't have done such a thing.‐Yahoo!知恵袋
回答
- He couldn't have done such a thing.
話者は、「彼はした」と事実として知っているか、「した」という情報を得て、もしそれが本当なら、なにか事情があったであろう、というよう(な)気持。
これは明らかに間違いです。
can't have doneが過去への推測しか表さないのに対して、couldn't have doneは過去への推量/反実仮想という意味があるからです。
can に比べると、could は、やや、自信がない表現です。たとえば、She couldn't be clever than me の場合には、「彼女がボクより利口であるはずがない」と言いながら、心のなかでは、「でも、ひょっとすると、彼女のほうが利口かも・・・」という気持ちが少しはある表現です。
推測の過程の違い、ということはあるかもしれませんが、そこまで話者の確信度に違いがある表現だとは思えません。
