In the latest clip for "The Flash," Dr. Martin Stein (Victor Garber) explains multiverse theory to Team Flash, introducing longstanding comic book terms like "Earth-1," "Earth-2" and more (via IGN). Stein also posits some interesting theories for the characters' dopplegangers on alternate earths, suggesting Earth-2 Joe West may be a Nobel Prize-winning physicist or that Barry Allen is an electrician in another life.

Starring Grant Gustin, Carlos Valdes and Jesse L. Martin, "The Flash" airs Tuesdays at 8 pm EST on The CW.