Ignore contrapositives at your peril

This blog has been defunct for a very long time. Apologies for that, and I promise to make it more active in the following days, weeks, months and years. We've been very busy with the book as the deadline approaches (September 1st with Routledge), and its led to all sorts of things getting neglected (like my cricket blog, can you imagine?). Anyway, so while digging around on the BitKeeper fiasco (remember last year's flame wars, which ultimately led to git being used for the Linux kernel?), we rediscovered the original flames concerning the use of BitKeeper on the kernel. RMS sparks things off, and there is the usual "don't you lecture me" responses, and Larry McVoy steps in with his "quit whining" diatribes, and then, amazingly, comes this interesting smackdown. Taken from the linux kernel mailing lists:

Larry McVoy: (In response to RMS saying "You are asking for the power to silence criticism. That is not freedom, that is a power."):

"Richard, the day that the GPL doesn't use it's power to force people to do things they may not want to do is the day that you get to make the above statement in public without getting flamed. Today is not that day. "

RMS: "Alas, by flaming me now you have made your own statement untrue."

In his response, McVoy doesn't acknowledge RMS's reply above. I wonder if its because he didn't get it, or because he realized he had been had comprehensively. In case you didn't get it, the structure of McVoy's claim is: If the GPL doesn't use its power to force people to do things they may not want to do then you get to make the above statement without getting flamed. But McVoy flamed RMS, so the antecedent is rendered false. Ergo, the GPL doesn't use its power to force people to do things they may not want to do. Poor McVoy, he shoulda studied the structure of contrapositives a little better.