I believe the main theme in the book Forrest Gump is man vs. society and you are capable of doing anything you set your mind up to, and try to achieve. The reason for me believing this is because many people doubted Forrest and called him names and harrased him because he was not as smart as everyone else. Forrest proved all those people wrong by getting out of the nut school to getting a full ride to a university to play football. Joining the army to getting into NASA and sent to outer space. Meeting the president and becoming a millionaire.