You're reading an imagined reply no one is giving. No one is disagreeing that testing ideas is important. Until you test, you never know if there are problems w

You're reading an imagined reply no one is giving. No one is disagreeing that testing ideas is important. Until you test, you never know if there are problems with your ideas that never would have occurred to you no matter hard you thought about them, and that makes testing invaluable. But sometimes some of the problems that testing would reveal, would also be revealed if you just thought and discussed your ideas more, and would cost vastly less time and effort (which is a very high bar when what you're testing is the efficacy of pedagogy for teaching people programming for the very first time). So presenting your ideas in a compelling way and opening up discussion can also be extremely valuable, and that's exactly what Bret Victor did.