Niven's own view of multiple timelines seems to be that they are absurd. He believes alternate-history fiction to be fantasies without the trappings of fantasy—that is, there is little science in them—so they are not the hard science fiction he prefers. Even so, he recognizes in the concept of alternate histories the opportunity to play with ideas, to ask "What if?" In the case of "There Is a Wolf in My Time Machine," one "what if" is "What would America be like if wolves (or dogs) were the dominant species?" Another is "What would a civilized wolf (or dog) society be like?" Yet another is "What would America be like without the internal combustion engine?" This third is a question typical of not only Niven's alternate timeline stories, but of those of many other writers. In "There Is a Wolf in My...