->''"''Know'' that flesh cannot mark steel. ''Know'' that steel may mark flesh. In ''knowing'' this, Zerthimon became free."''
-->-- '''Dak'kon''', ''VideoGame/PlanescapeTorment''

A motif quite often present in ScienceFiction and sometimes also in Fantasy: We have two civilizations, one is organic, possibly psychic, and tends to involve [[OrganicTechnology lots of tentacles and ichor]]. The other is inorganic, prefers metal or robotics. Often (but not always) "flesh" has connotations of hedonism and desire (especially hunger and lust) while "steel" has connotations of discipline and austerity, thus invoking EmotionsVersusStoicism. If there is a third faction, expect lots of PureEnergy [[EnergyWeapon Technology]].

It is not nature versus science as in most cases *both* are highly technologically advanced: Rather it is about biotech (or biomagic) versus inorganic tech.

Tends to be a big component of either a BugWar or a RobotWar, depending on which side humans count as.

See also: ForceVersusDiscipline, ScienceIsBad, LuddWasRight and most of the other similar tropes. StrongFleshWeakSteel is the literal version of this.

[[AC:Anime and Manga]]
* ''Anime/GargantiaOnTheVerdurousPlanet'': The gist of Human vs. Hideauze conflict. According to Chamber, the two forces represent fundamentally different survival strategies: the humans of the Galactic Alliance have formed a civilization capable of building advanced mechs to augment their weak bodies, while the [[spoiler: formerly human]] Hideauze survive through the sheer toughness of their bodies and have no need for civilization.

* In ''TabletopGame/MagicTheGathering'', the shards Esper and Naya in the recent 'Shards Of Alara' block represent steel and flesh (respectively).
** The metal world Mirrodin, which is inhabited by people, is attacked by machines seeking to transform everyone into a weird Frankenstein robot. The Mirrans are normal people (who happen to have metal grow naturally in them). Their enemy is the Phyrexian virus, which gives the infected a religious (literally) urge to spread the virus. One of their tenets is that flesh is weakness and should be replaced by metal.
*** [[http://gatherer.wizards.com/pages/Card/Details.aspx?multiverseid=218070 "Skin is the prison of the blessed and the stronghold of the heretic."]] —Argent Etchings, plate 64, passage 17.

* Forms the DrivingQuestion that underlines ''Film/{{Conan The Barbarian|1982}}'': What is the answer to the "Riddle of Steel"? Throughout the movie, three different answers are given:
** Conan's father takes a literal approach: "For no one - no one in this world can you trust. Not men, not women, not beasts. [Points to sword] This you can trust." This position winds up undone when Conan's father dies an undignified death, unable to even fight back while being torn apart by war dogs.
** Thulsa Doom, the movie's BigBad, however comes to the opposite conclusion, "What is steel compared to the hand that wields it?" This leads him to create a ReligionOfEvil to control people themselves, and is basically the main perspective Conan has to contend with.
** Ultimately, Conan goes on to TakeAThirdOption, with the answer that both tools and physical strength are nothing compared to resolve, and relying on these things alone is foolish. Conan's inner strength in the end is what allows him to destroy his father's sword being used by TheDragon, and then fight off Doom's mind control before taking his head off.
* The ''Franchise/{{Alien}}'' tetralogy, with the technology-using humans vs. the organic Xenomorphs.
* The movie of ''Film/StarshipTroopers'', with the alien bug castes as biological weapons vs. the human technology or [[HollywoodTactics lack thereof]].
* The second Franchise/StarWars trilogy featured humans (later clone troopers) against droids.
** And the ''first'' [[Film/ANewHope Star Wars]] movie contained the immortal words: "The ability to destroy a planet is insignificant next to the power of the Force."
*** Which begs the question: why did the Emperor bother to build not just one but two Death Stars, then? Pork-barrel projects?
* ''Film/PacificRim''. [[spoiler:The Precursors use organic tech to build huge, destructive Kaiju]]. Humans defend themselves with HumongousMecha, all pimped out with modern technology (including nuclear reactors). Notably flips the usual message of a Kaiju movie, with human ingenuity overcoming destructive nature (assuming evil aliens count).

* ''Franchise/StarWars: The Literature/NewJediOrder''.
** The Yuuzhan Vong are an extragalactic species who abhor inorganic technology to the point of considering it heresy. Their ships, armor, weapons, and communications are all taken by organic, specially crafted organisms. Their buildings are grown from a type of coral. Besides all that, they're wholly separated from the Force, unable to be detected or manipulated by its power.
* ''Literature/{{Schismatrix}}'' by Bruce Sterling brings us the conflict between the Shapers and the Mechanists. The Shapers work with genetics while the Mechanists prefer cybernetics.
* The future war backdrop of the ''Literature/BelisariusSeries'', with the two hyper-evolved offshoots of humanity at war with each other. One has become artificial and inorganic, the other claims to be "pure humans" but aren't. Rare case of the inorganics being the good guys.
* ''Literature/SecondApocalypse'' has aspects of this, we have the hyper-rational Dunyian vs. the Lust-obsessed Inchoroi, although there are hints they might come to the same conclusions in the end.
* In ''Literature/{{Leviathan}}'' by Scott Westerfield, the alternate World War One is like this, fought between the Clankers, who use {{Walking Tank}}s, and the Darwinists, who [[GeneticEngineeringIsTheNewNuke combine and alter DNA to create living airships and such]].
* The ''Literature/LegendsOfDune'' prequels are classic Machine vs Human. The [[Literature/PreludeToDune 1st trilogy]] doesn't have a Machine 'race' but is also Flesh vs Steel. On Arrakis, flesh, standard unarmored humans, is the most durable. War machines and even basic technology doesn't handle the sand, electrical activity and local wildlife very well.
** The prequels also emphasize this aspect by having many humans engage in hand-to-hand combat with machines. Why? It's never made clear, as the machines don't have [[DeflectorShield Holtzman field]] technology. The only possible explanation seems to be fanaticism.
* While the two do not come into direct conflict, overall, these are the two possible extremes taken by those reduced to an EmptyShell in ''Midnight'' by Dean Koontz. [[spoiler: One side transform into monstrous animalistic forms, in order to remove their higher thoughts and focus entirely on physical sensation. The other merge with technology and data, giving up their individual thought and so their desire to have emotions. The BigBad dreams of [[AmbiguousRObots blending the two extremes]] together, but the opportunity never presents itself.]]
* The planet Pyrrus in Creator/HarryHarrison's ''Literature/{{Deathworld}}'' has its entire flora and fauna determined to kill the human colonists, more specifically, the so-called "junkmen" who live in Perimeter, the only city on the planet. The "grubbers", who live in villages in, more or less, harmony with the native life, don't participate in the fight. The "junkmen" use guns, flamethrowers, poisons, and explosives to keep the native life at bay, while the native life, thanks to a higher-than-normal radioactivity of the planet, mutates almost as fast as the "junkmen" figure out new ways to protect themselves. Of course, the native life is slowly but surely winning, but [[BerserkButton don't tell that to a city Pyrran if you value your life]].

* In ''Series/StarTrekVoyager'' we have the Borg vs. Species 8472: Techno-zombies versus a biological species with an immune system so powerful it kills any other living creature they come into contact with.
** Of course, it's a decidedly one-sided conflict. When a single Species 8472 bioship (piloted by a single being) can destroy a dozen Borg cubes before they even finish their TheAssimilator speech, and the Borg nanites are useless against them, then you know the Borg are doomed. Oh, and about half-a-dozen of these bioships can merge their beams in a [[Franchise/StarWars Death Star]]-like manner to obliterate a planet.

* The Imperium in TabletopGame/{{Warhammer 40000}} relies on mass-produced vehicles and weapons, non-disfiguring biological implants, and [[TheDeterminator sheer stubbornness]] to face mutated Chaos monstrosities and the [[HordeOfAlienLocusts Tyranid swarm]].
** The Eldar use some psychic powers and a lot of hyper-advanced technology for everything, while the [[EvilCounterpart Dark Eldar]] are vat-grown and have a fondness for growing strange monsters and grafting bits onto themselves.
** It's heavily implied that the Necrons and the Daemons of Chaos wage war on each other regularly, intending to destroy each other. This is good, and bad, because if Chaos is destroyed, our universe and the Warp will not become one, but the Necrons will eat most life in the galaxy and keep the rest around to breed new snacks (and then eat them again. Repeat for all eternity). If Chaos wins, the Necrons are no longer a threat but the Chaos Gods' plans continue.
** Strangely enough, the literal version happens comparatively rarely: Tyranids exist only to feed on biomatter, which Necron tomb worlds tend to be poor in, [[OmnicidalManiac for obvious reasons.]] And while Necrons exist to destroy all life in the galaxy, they need to be woken up (say, by something invading their world and alerting the tomb's defense systems, which the Adeptus Mechanicus can't go five minutes without doing).
* The Slaad and Inevitables from most versions of ''TabletopGame/DungeonsAndDragons''.
** And the [[{{Expy}} Proteans]] and Inevitables in ''TableTopGame/{{Pathfinder}}'' do this as well.
* This is what happens when you combine [[TableTopGame/IronKingdoms WARMACHINE and HORDES]].
* This is the principle conflict in TableTopGame/{{Mortasheen}}, with the human-dominated, technophilic civilization of Wreathe versus the chaotic city of mutants and monsters that is Mortasheen. The latter are our heroes by the way.
* In ''TabletopGame/HcSvntDracones'' Pulse, a MegaCorp specializing in athletics equipment, performance-enhancing drugs, cosmetic surgery, and BioAugmentation; has a strong rivalry with Applied Sciences and Robotics. Though their use of biotech is strictly medicinal, they use inorganic technology for their other products. Transcendent Technologies Inc on the other hand, which produces things like living armor, living ships, and bio-implants that warp reality, no one else really wants to associate with them much because their products have a tendency to kill their owners. And their biggest rival, Progenitus, also produces biotech, though almost exclusively for non-elective surgery and cures.

* ''Toy/{{Bionicle}}'' seems to be hinting at tension between the biomechanical Matoran and the mostly organic Agori. The Agori of Bota Magna, in particular, take it to the extreme and have rejected all mechanical technologies, instead using primitive weapons and plant-based armour.

* Part Dak'kon's teachings in ''VideoGame/PlanescapeTorment'', who puts a spin on the origin story of the Githzerai (and Githyanki) from ''TabletopGame/DungeonsAndDragons''. The Gith were slaves of the illithids, psionic mind-controlling brain eaters, but at one point a Gith named Zerthimon finds a steel knife embedded in the skull of a corpse. He is surprised by the concept that something might die without becoming food for the illithids. This leads him to formulate the Scripture of Steel: "Steel may mark flesh, but flesh cannot mark steel." And he reasons that while the Illithids [=*know*=] flesh and can shape it to their will, they do not [=*know*=] Steel...
* ''VideoGame/StarCraft'' has aspects of this as well. With the technological Terrans, psychic Protoss and biological Zerg.
* ''VideoGame/KrushKillNDestroy'' has the "Evolved" (mutated humans riding giant insects) versus the "Survivors" (surviving unmutated population using high-tech equipment) the sequel adds a race of sentient tractors as well. Making it bridge the entire scale.
* In ''Point of View'' (a GameMod for ''VideoGame/HalfLife1''), it is stated that a factor of Xen's hostility to humankind is that humans use technology, while the Xen aliens use controlled evolution, and their "machines" are organic. (Note that it's strictly {{Fanon}}.)
* ''VideoGame/SystemShock'' and especially ''VideoGame/SystemShock 2''. SHODAN thinks flesh is worthless and weak. The Many is all about flesh.
-->'''SHODAN:''' Your flesh, too, is weak. But you have... potential. Every implant exalts you. Every line of code in your subsystems elevates you from your disgusting flesh.
-->'''The Many:''' Do you not trust the feelings of the flesh? Our biology yearns to join with yours. We welcome you to our mass. But you puzzle us. Why do you serve our mother? How can you choose cold metal over the splendor of the flesh?
* The factions from VideoGame/TotalAnnihilation. CORE who rely on robotics and ARM who use cloning.
* ''Videogame/WorldOfWarCraft'' has its share of this trope with some of OrderVersusChaos thrown in the mix, as featured more extensively in the Ulduar instance, which showcases the ancient conflict between the [[SufficientlyAdvancedAlien Titans]] and the [[EldritchAbomination Old Gods]]. Lore-wise, shortly after the Titans had finished crafting Azeroth, they had intended it to be taken cared of by [[LivingStatue humanoids made of solid rock or metal]] (like the Earthen, which later became the [[OurDwarvesAreAllTheSame dwarves]]) and MechanicalLifeforms (like the Mechagnomes, which became the [[OurGnomesAreWeirder gnomes]]) to maintain order and stability. When the Old Gods appeared, they hexed Azeroth with the Curse of Flesh, which turned the Titans' seed races into fleshy, mortal creatures in order to [[TheVirus facilitate assmiliation]]. The respective factions' {{Mooks}} thus follow this trope, with the stone-like [[AmbiguousRobots Titanic Watchers]] vs. the viscous [[{{Cthulhumanoid}} Faceless Ones]] ([[spoiler:Some of the former were [[BrainwashedAndCrazy brainwashed]] by the boss of the Ulduar instance [[SealedEvilInACan Yogg-Saron]].]])
* ''VideoGame/{{Fracture}}'' is about a war between The Atlantic Alliance, which is devoted to advancing the technological prowess of humanity (cyborgs) and the Republic of Pacifica which is devoted to enhancing the human genome (bioengineering).
* ''Warhammer 40000: Rites of War'', an old RTS game based on the ''TabletopGame/{{Warhammer 40000}}'' universe plays the above mentioned three-way version of this dynamic perfectly: the all-consuming Tyranids (Flesh), the technocratic Imperium of Man (Steel) and the highly psychic Craftworld Eldar (Energy).
* ''VideoGame/CivilizationBeyondEarth'' has this dynamic going on with the technological affinities the various factions can adopt. Harmony (Flesh) believes that that their new planet is a paradise and strive to avoid repeating the same mistakes as humanity did on Earth; they want to integrate Humanity fully into the alien environment by turning their citizens into [[HalfHumanHybrid half-human, half-alien hybrids]], their military also has infantry in biological armor, tanks built with OrganicTechnology and genetically engineered alien monsters within its ranks. Supremacy (Steel), meanwhile, believes mankind's technology is it savior and will allow them to live in any environment they choose. They turn their citizens into cyborgs, along with developing advanced artificial intelligence and robotics. Purity (the final affinity), rejects the rampant transhumanism of the other two affinities; though it does use gene-therapy to cure disease and tweak human performance. They also specialize in PoweredArmor, heavy artillery and flying battleships so they kind of take up a place in the middle.
** The ''RisingTide'' expansion adds hybrid Affinities. The Supremacy / Harmony hybrid makes their military units into bizarre mergers of cybernetics and engineered flesh like the Nanohive (a walking tank that outputs swarms of nanomachines to grind away their enemies) and the Aquilon (an AirborneAircraftCarrier described by the developers as a "meat zeppelin").

* Hinted at somewhat in ''Webcomic/QuentynQuinnSpaceRanger'' ... the Kvrk-Chk, are largely living berserker battletanks, and the Empire forced them into surrendering by [[StarKilling incinerating one of their systems]]. It's further implied by the biotech quarters aboard the Sapphire Star... biotech based civilizations are noted as being rather rare, and are regarded as technologically inferior due to the many inherent problems with organic technology.
* In ''Webcomic/AliceGrove'' [[http://www.alicegrove.com/image/110864583014 Ardent and his sister Gavia represent this split]] although it's limited to philosophical argument rather than violent conflict.

* ''Franchise/{{Transformers}}'' has used this trope on a few occasions. In both ''Anime/BeastWarsII'' and ''WesternAnimation/BeastMachines'', the heroic, technorganic Maximals fight against the evil, purely robotic Predacons/Vehicons. This situation was inverted in ''[[Anime/TransformersRobotsInDisguise Robots in Disguise]]'', in which the heroic, completely mechanical Autobots fight the evil, technorganic Predacons.
* ''WesternAnimation/GeneratorRex'': The nanites turn most people into freakish, warped monstrosities, while Rex gets the ability to produce gleaming, futuristic machines to fight them.