There are two important ideas to consider in the novel The Martian. The first is how we function in isolation. Mark Watney perseveres in his life on Mars through sheer will, creative problem-solving, and resilience in the face of seemingly insurmountable odds. Watney figures out how to grow food on Mars, how to travel thousands of kilometers in a modified rover, how to dismantle a rocket and eject himself into space—all completely by himself. The cost, though, is nearly his sanity. He's desperate for companionship, for connection. The diary that he keeps is evidence of that. His relief at finally being able to contact NASA is evidence as well. Even though he has this desire for companionship, his isolation has given him a sense of self-sufficiency, demonstrated when he flouts NASA's instructions on a regular basis. This stubbornness and risk-taking could get him killed, but they don’t. Instead, they enhance his ability to survive.

The other important idea to consider in this novel is the concept of cost-benefit analysis. This is primarily demonstrated when NASA is trying to plan Watney's rescue mission. Time and time again, plans fail. The engineers cut corners for the sake of time, which is considered necessary. Then a lug nut comes unscrewed, and a food drop explodes during take-off. The most significant example, though, is the "Rich Purnell maneuver." This rescue plan would keep the crew of the Hermes in space, sending them back to Mars to pick up Watney. It also risks five lives (not to mention millions of dollars) to save one man. The extremes to which institutions like NASA and JPL will go, and the moral decisions individuals like Henderson and the crew members of the Hermes are forced to make, call into question the value we place on human life. Grappling with this question is one of the most satisfying aspects of the novel.