Wow. This thread is stupider than I ever dared hope. It's almost beautiful in the perfection of its stupidity. Here, let me add to it...
I am all for dialect continua (Isa and I have discussed this before in other threads), but in a micro-level geographical view such that the Scandinavian languages may be said to in a sense form one such continuum such that speakers the next town over may understand one another, and the next town over, etc. (hence forming a sort of chain with unintelligible end points, which I am sure is evidenced by speech varieties on either side of the Ru/Ukr border). That is something different than saying, categorically, that they are all dialects of one supposedly primary macro-language. There is really very little to substantiate that idea, particular given the insights shown via Swadesh's glottochronology
and the various challenges to it. The insight there, of course, is that languages develop from the proto-language
(not from one another!) at different rates but core vocabulary remains at about 85% per millennium. This was challenged by people who came up with examples like Icelandic and Lithuanian which seem to show a slower rate of change, but if this is averaged out with languages on the other end (those with a faster rate of change), what you see is more or less a stereotypical bell curve (also, the 85% that is retained is basic vocab you wouldn't expect to be replaced anyway, like the stuff in Swadesh's famous list, so there is also kind of a "yeah, so what?" element here). What does this tell us? Unless you can peg its development to a relatively specific time period wherein speakers of what would become language Y separated from the main body of speakers of X (say, the Boers arriving in S. Africa), talking about X as a dialect of Y says more about you than it does about linguistic history. You cannot really look in isolation at vocabulary or syntax and say "aha! This proves that this is a dialect of that!", as though their shared parentage is of no consequence. I would think that a great many of the correspondences you see between Ukrainian and Russian are a result of this shared genetic affiliation, rather than evidence that Ukrainian somehow budded from Russian (doesn't history suggest otherwise? Wasn't Kiev the capital of Rus'?). Now, I am shamefully and happily ignorant about such things as relate to Russian and Ukrainian, but I do know that as a Russian student for about 6 years who also interacted with a fair share of Ukrainians in that time, they could understand me much easier than I could understand them (though we were able to communicate basic ideas quite well). A comparison could perhaps be made here between the relationship of Portuguese to Spanish, which nobody in their right mind would call dialects of the same language! But they certainly do share a common history, up to a point.
You could do with some education in historical linguistics and typology, Vladik. I recommend Trask's introductory text (I just sold my copy, but I think it's just called "Trask's historical linguistics") or, if you are more advanced, Croft's "Typology" (one of the Cambridge series of textbooks in linguistics) or Comrie's "Linguistic Typology" (this was what got me interested in typology and genetic classification).