I'm not quite sure about the philosophical implications here, if there are any, but here goes.
Take the following two sentences:
(1) "Gov. Spitzer could have been more honest with the people of New York."
(2) "Gov. Spitzer could have been a potato."
The interesting thing about these two sentences is that the word "could" is being used in a very different way in both of them. I am not quite sure if I can say why succinctly, but I'll try. Basically, in one sense they are both true. But in another sense (1) is obviously true but (2) is obviously false.
So Wittgenstein talks a lot in both the Tractatus and the Investigations about how we, as speakers, can be misled by the grammar of our language into believing that we are saying something different than what we are really saying. I think that these two sentences are an example of this. But I think that (a) it's a problem specific to English, in that the use of cases in languages like French and Latin avoid it, and (b) it's only a problem for analytic philosophy, in that only some philosophers would see these two sentences and conclude that there is a possible world where Gov. Spitzer is more honest and that there is a possible world where Gov. Spitzer is a potato.
The mistake is to think that what I am talking about is something about the essence of what constitutes being Gov. Spitzer, and not about how the English language works.
Consider:
"I could have gone to work today."
"I could have gone to work today, but I didn't."
"I could have gone to work today, and I did."
"I went to work today."
"I could go to work tomorrow."
"I could have died at birth."
"I could have been born a girl."
"I could have been a six-footer."
"I could still turn out to be a six-footer."
"I could be a six-footer."
"If it hadn't had been for the oxygen deprivation, Lisa could have grown up to be a strong and healthy woman."
"Tiny Tim could wake up tomorrow and be the healthiest boy in London." (With God, all things are possible.)
"I could be more honest with myself."
"I could be stronger, if I worked out more." ("I would be stronger, if I worked out more.")
"I could be the President of the United States of America."
"I could be the King of France."
"I could be a potato."
"I could be a butterfly, dreaming it was a... dude."
I have to go to bed now. But this has something to do with a question of ethics:
"Gov. Spitzer should have been more honest with the people of New York."
"Gov. Spitzer should be a potato."