@thebluepanda, I was reading the post and than this discussion, what @dwinblood want's to say is, a handhold device with out a cord that would enable you to communicate with a person on the other side of the planet in real time was "impossible" in the 80's. Yet we have phones today, to simplify even more, he reffers to your use of words like "can't" or "impossible", that's what "bugs" @dwinblood, as he explains it:

To know the absolutes on impossibility and possibility you'd need to believe in some omniscient Godlike being, but you would need to take it further than that. You would also need to assume that you are that being since you deal in absolutes. ;)

So, @dwinblood is attempting here to teach you not to "toss around" these words like that, especially in a intellectual discussion.

IMHO @dwinblood may have reacted a bit too "aggressively" on this what you may have interpreted as an "attack" on you, but it's not and In the end all he wanted is to teach you something.