Punctuating a phrase leading up to a question

Question

In formal writing (like a technical paper), is there a generally accepted way to punctuate the break between an introductory phrase and a question in a sentence like this?

Let's ask ourselves (--insert punctuation here--) what would a world without computers look like?

I know that you could reword it to avoid the direct question, but that's not what I'm asking about.

A few possibilities occurred to me:

1. Let's ask ourselves: what would a world without computers look like?

2. Let's ask ourselves - what would a world without computers look like?

3. Let's ask ourselves... what would a world without computers look like?

4. Let's ask ourselves, what would a world without computers look like?

5. Let's ask ourselves, "What would a world without computers look like?"

Which would be the best to use and why?

Answer 1

I believe that 1) is the best choice. According to this source, a colon is used "before a list or an explanation that is preceded by a clause that can stand by itself."

While 5) also seems correct, and the others are at least defensible, I think 1) works best.

Answer 2

Regarding each of your offered choices:

1. Let’s ask ourselves: what would a world without computers look like?
   This one isn’t too terrible. It might be one of those places where you may wish to follow the colon with a capitalized word, since you are introducing a complete independent sentence. It depends on your publisher’s internal style guide whether to do that.
2. Let’s ask ourselves – what would a world without computers look like?
   This isn’t really my favorite use of a dash.
3. Let’s ask ourselves . . . what would a world without computers look like?
   This is certainly the worst possible choice. That isn’t want an ellipsis is for. It looks like some ten-year-old’s text message ... you know ... the people who know no punctuation than an (unspaced) ellipsis ... so that is all they use ... it looks horrible.
4. Let’s ask ourselves, what would a world without computers look like?
   Not my first choice, although not just crud like the previous one.
5. Let’s ask ourselves, “What would a world without computers look like?”
   If you have to choose from one of these five, then this is the best choice.

However, given my druthers, me I would rather write:

• Let’s ask ourselves what a world without computers would look like.

Because it is now an indirect question, there is no need of terminating question mark, either. But that wasn’t one of your choices.

Answer 3

If it were up to me, I would choose either (1) or (5), most likely (1). I can't back up my claim with anything but opinion and a humble amount of experience, unfortunately. I find 2, 3 and 4 to be a little awkward, while 1 presents the question as a one-item list (which makes sense to me) and 5 formats the question like dialogue, which is something that people are used to.

But as the comments have mentioned, depending on the tone of your writing the use of "Let's ask ourselves" in general may be a little too informal.