A Columbia University law professor stood in a hotel lobby one morning and noticed a sign apologizing for an elevator that was out of order. It had dropped unexpectedly three stories a few days earlier. The professor, Eben Moglen, tried to imagine what the world would be like if elevators were not built so that people could inspect them.
Mr. Moglen was on his way to give a talk about the dangers of secret code, known as proprietary software, that controls more and more devices every day.