The Roman readers, many of whom would at one time have been in the army, would have had no trouble with Caesar's austere narrative; they would have found it complete as it is. They would have known how to read the shorthand. -V S Naipaul
My question is what changes in meaning will occur if I use might have or the simple past instead of would have. What does would have mean in a sentence which does not have an if clause? It seems that Naipaul has not used would have for an unreal past.
Commonly, we use would have + past participle to talk about something you wanted to do but didn't. This is nearly similar to the third conditional, but we don't need an 'if clause'.
1) I would have called you, but I did not have your number.
But in Naipaul's paragraph, the Roman Readers "were" in the army and there was no "did not" there.