Apropos of the difference between errors of fact and errors of reasoning, Carl Zimmer (blogger at Discover Magazine) asked Bill Chapman, a University of Illinois climate scientist, about George Will's recent bungling of Chapman's data as well as the Washington Post's defense of Will.  Chapman said:

Since their statements were based on the end of the previous year, and more importantly the end of 1979, the statement ‘global sea ice levels now equal those of 1979′ just didn’t make sense any more. We have received 80-100 emails from confused people who had read George’s column and looked up the graphs on the Cryosphere Today [one of the center’s web pages] and said they came to a different conclusion, or, could we point them to the report that said that Feb 1979 and Feb 2009 sea ice area was nearly the same. We had to post the current and corresponding 1979 values to avoid the inconsistency that readers were noting. After doing some googling, it appears that Daily Tech article got repeated on a lot of blogs, so it’s not surprising George Will came across it at some point. Still it was sloppy for them to not double check with the original source and it really points out the danger of making any conclusions on climate change based on any two days in history. I really wish they would have contacted us at some point to avoid this.

Our goal is to present the data in as concise and useful format as possible for interested users. Whether the Washington Post decides to publish a correction is up to them.

Here's what Will wrote:

As global levels of sea ice declined last year, many experts said this was evidence of man-made global warming. Since September, however, the increase in sea ice has been the fastest change, either up or down, since 1979, when satellite record-keeping began. According to the University of Illinois' Arctic Climate Research Center, global sea ice levels now equal those of 1979.

What Chapman points out is important.  It's not only the misrepresentation and the laziness of it all (Will didn't bother to inquire with them, while Zimmer and others have), it's the fact that he made some kind of spectacularly giant inference on the strength of two isolated facts.  Even if those facts had been true in the sense he alleged, there is no way he should have been allowed to make that inferential claim without relying substantially on the common sense of the relevant experts–who, by the way, nearly unanimously disagree with him.  

It does not advance the public understanding if scientists must continue to debate intellectual children who (1) have no basis for disagreeing with them (2) don't accurately represent the views of the scientists in question and (3) accuse everyone else of being hysterical.  That's more or less what the Post considers meaningful public discourse–worthy of publication in their paper and syndicated across the country.