Mysteries are a key part of Westworld’s programming — just ask any fan who has turned to Reddit to pen a lengthy theory about what’s at the center of the maze. The fourth episode of the HBO show’s sophomore season referenced one of the most famous riddles in all of history in its title, leading some fans to wonder: What is the Riddle of the Sphinx, what’s the answer, and what does it have to do with Westworld?

This post contains spoilers for Westworld Season 2, Episode 4. There are also spoilers for a two-millennia-old riddle.

Nobody explicitly asks the riddle of the sphinx in the episode, so the specifics might be a mystery if you didn’t have a copy of D’Aulaire’s Book of Greek Myths when you were a kid. Here’s the backstory: In the Greek myth, a Sphinx, that creature with the body of a lion, wings of a bird, and the head of a human woman, stands outside the city of Thebes and asks passersby a riddle. If they can’t answer, she would eat them.

Here’s the riddle of the sphinx referenced in Westworld

Which has one voice and yet becomes four-footed and two-footed and three-footed?

Other versions of the myth frame the question slightly differently, asking what has four feet in the morning, two in the afternoon, and three at night. The answer is the same regardless: It’s man. As a baby, he crawls on all fours, stands upright in his prime, and uses a cane in old age. Only the Greek hero Oedipus was able to answer the Sphinx and avoid being devoured.

Oedipus and the Sphinx of Thebes, Red Figure Kylix, c. 470 BC
Oedipus and the Sphinx of Thebes, Red Figure Kylix, c. 470 BC

What does this have to do with Westworld? Well, there isn’t a Greek World populated by actual Sphinxes and Hydras (maybe that’ll be in Season 3), but the main plot of the episode is all about aging and immortality. James Delos is old and dying, but William’s attempts to give his father-in-law eternal life don’t involve a third leg. Instead, he’s trying to implant his consciences into a Host’s body, resulting in immortality.

As the events of the episode reveal, it’s not working. James Delos’s consciousness keeps breaking down. William is trying to solve one of the biggest questions any mortal has ever had to grapple with: Can you live forever. The 149 failed attempts to extend his father-in-law’s life suggest that achieving immortality is impossible, and that death and decay are as inevitable as the setting sun. Pretty heavy stuff.

As far as thematic references go, this is much deeper than the cover of Kanye West’s “Runaway” from a couple weeks ago in an episode that featured a literal toast to the assholes. Riddles and references are a big part of the Westworld aesthetic, but the thematic connections are often pretty shadow. “The Riddle of the Sphinx” was a slightly more rewarding puzzle than most.

New episodes of Westworld Season 2 air on Sunday nights at 9 p.m. Eastern on HBO.

Photos via Carole Raddato/Creative Commons, HBO