During the last few years, I've written a lot of short scientific articles (in everyday language as far as possible). They're generally about future ideas in science, and the best have been collected into a book posted at http://figshare.com/articles/Future_Science_and_Religion/1619771 Their origin confused me as much as Yesterday's origin confused Paul 50 years ago. I've heard that he spent days convinced that it had already been written, and that he must have heard it on the radio or something. The last article in my collection is called "How did Paul McCartney write the song Yesterday?" It suggests the song by the Beatles and my collection of science articles both resulted from a time warp. Paul and I were inspired by things that indeed already exist, but their existence is in what we'd call the future. By inspiring us in the 1960's and the 2nd decade of the 21st century, they became part of the present because we wrote them down.