Re: theory suggests VS theory would suggest
They do not have exactly the same meaning. "I was 10 ..." is given as a fact. "I would have been 10 ..." has the idea of "The information (and/or memory) that I have suggest to me that I was 10". The certainty of the speaker actually being 10 at the time of leaving is not so great.
Originally Posted by Alamshar
Similarly, "Theory suggests ..." is factual. "Theory would suggest ..." is, as you say, more indirect, and it is therefore less certain.
In practical terms, there is no significant difference, but I don't think we can say they have the same meaning.
The difference is clearer in "Chomsky says .." and "Chomsky would say ...". In the second of these it may very well be that Chomsky has never said the words that follow. The speaker believes that Chomsky would say those words if he were to speak on the subject (based on the impression that the speaker has gained of Chomsky's thinking).
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