JULES ERATOSTHENES BROWN (Todd Cameron Brown, Josh Keaton), in the Back to the Future franchise, is the elder son of Dr. Emmett L. Brown and his wife, Clara Clayton Brown. He has a younger brother, named Vern.. Their parents named the boys after the great author of speculative fiction, Jules Verne. In addition, Emmett named Jules after Eratosthenes, the Greek philosopher and mathematician most famous for his algorithm, or Sieve, for selecting out all the prime numbers from a given set of counting numbers.