Conditional perfect vs. future perfect

Question

What is the difference between saying "Yo habré estado soñanda cuando vi el unicornio" and "Yo habría estado soñanda cuando vi el unicornio"? The intended meaning is "I must have been dreaming when I saw the unicorn."

Another example: "¿Quién habrá hecho tal cosa?" and "¿Quíen habría hecho tal cosa?" Intended meaning: "Who could have done such a thing?"

Last example: "¿Cuándo habrá aprendido él español? Era en trabajo todo el tiempo." and "Cuándo habría aprendido él español? etc." Intended meaning: "When could he have learned Spanish? He was at work all the time."

Are both versions correct in each instance? If so, is there a subtle difference in meaning?

Answer 1

I agree with Mark-W, but also I think it depends on what you are using the conditional perfect for. How the conditional perfect compares with the future perfect tense depends on whether you are using it to express the future within the past or whether you are using it to express conjecture or probablility in the past.

OK, yes, that makes it still clearer, "would" expressing future w/in past and "could" expressing probability in past. - Higgler, Oct 11, 2009

Answer 2

I must have been dreaming... "Tengo que haber estado soñanado cuando vi..." It's common to use a form of "tener que + the infinitive haber + estado + present participle" to say that someone must have been doing something.

"Quién habría hecho tal cosa?" vs. ¿Quién habrá hecho tal cosa?" In the first case the proper translation would be "Who could have done such a thing?" and in the second case it would be "Who can have done such a thing?" The conditional tense is used to express probability in the past [example: Quién sería? Who could it be?] and the future is used to express probability in the present [example: "Quién será? Who can it be?]

Therefore - "Cómo habría aprendido español? Estaba todo el tiempo en el trabajo." How could he have learned Spanish? ("Cómo habrá aprendido..." would be: How can he have learned Spanish.)

I haven't seen the "tengo que haber estado" construction. I'll keep a lookout for it. But it's a little weird: "I have to have been..." Cond'l perf as "probability in the past" agrees with QFreed's answer above, which I think clears up the ambiguity. - Higgler, Oct 12, 2009

Answer 3

Thanks, everybody. This has been bothering me for a while because I use full-sentence flashcards and, when I come to this sort of thing, I never know what form to use. I can't believe how fast you responded.

Answer 4

"I must have been dreaming when I saw the unicorn." expresses a certainty about the past, so I don't think you should use the future or conditional tenses.

You are currently sure (present tense) that when you saw the unicorn (preterite since it is a specific completed action in the past) you were dreaming (imperfect since it set the scene for something in the past.)

So by your reasoning it should go simply "I am sure that, when I saw the unicorn, I was dreaming" -- "Estoy seguro que, cuando vi el unicornio, estaba soñanda." - Higgler, Oct 11, 2009

Answer 5

This is a bit complex, as it gets into time/mode/aspect issues. I think that the future tense indicates more probability of an event (it is more likely to have occurred). A little more emphasis on its "real" occurrence vs. its conditional occurrence.

Thanks. So I guess future perf suggests "I will have been," "Who could have done," "When could he have" -- and cond'l perf suggests "I must have been," "Who would have done, "When would he have" or some such. - Higgler, Oct 11, 2009