By far the most important technique for effectively engaging in such a debate is the Socratic method (AKA "precision questioning" at Microsoft - if you work the

By far the most important technique for effectively engaging in such a debate is the Socratic method (AKA "precision questioning" at Microsoft - if you work there and you haven't taken this class, you should, if it's still being offered). Basically you just carefully ask questions which, little by little, bring the things to the point where both sides could accept the resolution. Note that this works both ways, and the other side could (and IMO should) do the same to you, and _you_ could very well discover that your assumptions were wrong. That way instead of engaging in a battle of egos (which almost never works), you get to engage in removing unjustified assumptions and finding the mutually acceptable solution. This does require some skill, and more so if the other side also knows these techniques, but I'd argue that this is the most respectful and effective way to argue at work, and the only one I know which nearly always produces good outcomes. This does assume the argument is being conducted in good faith though. If it's not, you'll only irritate the opponent as their logic gaps and lack of good faith will become blindingly clear.