In many fields—biology, sociology, anthropology, economics—there are laws that seem at first to hold generally, but only because the author did not look beyond the limits of his country, or his continent, or his period of history. Laws thought to express a universal moral behavior or universal forms of religious worship turned out to be limited laws when it was discovered that other cultures behaved differently. Today, it is suspected that there may be life on other planets. If so, many laws of biology, which are universal with respect to living things on earth, may not apply to life elsewhere in the galaxy. Apparently, then, there are many laws that are not accidental, but that hold only in certain limited regions of space-time and not universally.