The greater good is the idea that it's best to optimize the "greatest good for the greatest number of people". This idea is sometimes also referred to with the phrase, "the ends justify the means."
The philosophy of the "greater good" can be used by heroes and villains alike to justify all sorts of crimes, up to and including murder.
The concept of the greater good is something that Clark Kent has repeatedly refused to consider except as a last resort, especially if it involves condoning murder. This is true even when billions of lives are at stake. (Legion)
Clark's approach in stark contrast to many of his allies, who believe in the greater good.
- Rokk Krinn and the Legion of Super-Heroes were willing to kill Chloe in order to destroy Brainiac. Clark stopped them and insisted they find a better way: eventually they discovered they could combine their powers to generate an EMP and then remove Brainiac's nanites, while sparing Chloe's life. (Legion)
- Oliver Queen and his team of heroes incapacitated Clark with green kryptonite in order to attempt to kill the human Davis Bloome. Chloe came up with the idea to use black kryptonite to separate the human Davis from the monster Doomsday. (Doomsday)
- As of Season 9, Chloe has started to monitor her own team of heroes, going so far as to install hidden cameras in Clark's home (Kandor) and Oliver's belt buckle (Rabid). She also has started monitoring Oliver's emails (Absolute Justice, Part 1) and Clark's voicemails. (Idol) She even staged an elaborate hoax, to snap Oliver out of his self-pity and alcoholism. (Roulette)
- Oliver has repeatedly shown himself willing to kill for the greater good. (Odyssey,Doomsday)
- Clark has repeatedly saved Lex's life, even though doing so is almost certainly against the greater good.
- Lex Luthor also believed he was acting for the greater good. He justified many of his crimes as necessary in order to fight an alien invasion. (Prototype)
- Clark: Jor-El wants me to kill the person who will be the vessel. Zod will possess a human form, destroy Earth just as he did Krypton. But I can't kill anyone. You of all people should know that.
- Lionel: Clark, the real test of a hero is knowing when the greater good will be served by an evil act. To save the Earth, the cost of one life is the price that must be paid.
- Clark: Even if that life is your son? Lex is the vessel of Zod.
- Season Five, Vessel
- Zor-El: (to Kara) General Zod is no ally of mine. He believes a civil war will bring about a new Krypton. My work is about Rao's prophecy, a new beginning – a greater good for us all.
- Kara and the Chronicles of Krypton, Episode 3
- Lana: You're Green Arrow. You're better than this.
- Oliver: You sound like Clark.
- Lana: If we want to fight for the greater good, maybe we all have to be a little more like Clark.
- Season Eight, Bride
- Oliver: Kick his ass, Clark. Get this thing out of our lives, once and for all.
- Clark: You want me to kill him.
- Oliver: No. I need you to kill him.
- Season Eight, Beast
- Chloe: I must have thrown a million green rocks away and I've never really saved you. Now, I can.
- Clark: Chloe, listen to me, this is your life that we're talking about. Don't do this!
- Chloe: Clark, if there's one lesson I've learned from you, it's that choosing the greater good is never a sacrifice.
- Season Eight, Beast