They write, "It makes for very interesting speculation, but the amount of evidence is not large".

Just said he had a few interesting speculations for you.

It was an interesting speculation, what his life had been like.

It is an interesting speculation by what means the Book lost its old position in this country.

This is not only an interesting speculation, but one which nearly concerns a vital matter.

Which makes you think and gives rise to some interesting speculation.

Put all those data together and you have the material for some very interesting speculation, to say the least.

I hesitate to call this impossible, but it does lead to some interesting speculation.

That's all interesting speculation, but we want to decide what to do.

The location of the south western end is an interesting speculation.