Hmm, I must be misinformed about the term "virtually impossible". I always thought it meant that it was completely, totally, absolutely impossible. Has English changed that much over the last few years?
Look up the adverb "virtually." It allows for exceptions. The whole point of putting a modifier in front of an absolute word like "impossible" is to
modify it.
- The performance was virtually flawless. There were some barely noticeable intonation problems in the brass section.
- The food at Sam's Bistro was virtually inedible. It did not actually make me throw up.
- President Bush is virtually incapable of telling a joke. Occasionally he does so unintentionally by mangling his sentences.
People grumble about the prevalence of "nearly unique." They say "uniqueness" is absolute, it's either there or it's not. And they miss the point, because adverbs like "nearly" allow us to express relative conditions using absolute words.
If something has no possibility of occurring then that is "literally impossible". People mistakenly use that phrase in place of "almost impossible".
On a scientific website like ours, it should be enough to just say "impossible" when we mean "not possible." People say things like "I literally fell over laughing" as in intensifer, in a situation where we know dadgum well that they did not fall over since there are no Band-Aids. Their command of the language is insufficient to express to us
why the situation was so funny, so instead they express to us
how they reacted to it. We can forgo the criticism and simply pity them for their inarticulateness.
But "literally impossible" should be equivalent "truly impossible, I mean it, not just the American legal definition of 'true beyond a reasonable doubt'." Obviously the word "literal" is losing its meaning and will soon need to be supplanted by something stronger.
I use "virtually impossible" myself to mean "almost impossible", but there is probably another shade of meaning.
Hmmm. My sociolinguistic group uses "virtually" as a stronger modifier than "almost." "Almost impossible" to us means, "There are people out there who have dropped out of school and gotten away with it and you may meet one, but this won't happen in any of your friends' families because you're all perfect parents." "Virtually impossible" means, "There are people out there who have dropped out of school and gotten away with it, but they're so rare that the L.A. Times can't find a poster child for the phenomenon to put on the front page."