Once upon a time, there was Comfort, and there was Safety, and they were very close. Comfort could live without Safety, and Safety could live without Comfort; but as they realized they were better as a pair, they preferred not to be apart.

All went well for a while, until people started to mistake one for the other—saying, I want comfort, when, in fact, what they meant was, I want safety, and vice versa. At first, Comfort and Safety found the confusion amusing. But as it increased, th...