works of science fiction all begin with the idea of framing a hypothesis - a new thing or "novum". the most common of these hypotheses is likely time travel, although there are many thousands of distinct alternate realities used in books and movies that do not utilize time travel as a hypothesis. it is suvin's opinion that some of the most commercially successful works of sf have only used this idea of framing a hypothesis as an ornament. in other words, suvin believes that the most popular mainstream sf works, like "star wars", are not truly sf at heart—they simply utilize the genre as a way to take advantage of the special effects and uniqueness that go along with the genre.