There are many differences between Science Fiction and Fantasy, but some things blur the lines between them. Regardless, there are lots of ways that tropes from both can overlap.
Sister Trope to Gun/Sword Counterpart and Animal Counterpart, compare Magic Versus Science, Mother Nature, Father Science, Speculative Fiction Tropes, Clarke's Third Law, Sufficiently Analyzed Magic and Modern Day/Sci-Fi RPG Class Equivalents. Not to be confused with Fantasy Counterpart Culture, though the two could overlap.
Tropes:
- Alchemy Is Magic — Chemistry Can Do Anything
- All Myths Are True — All Theories Are True
- Anti-Magical Faction — Anti-Human Alliance (aliens to humans) / The Men in Black (humans to alien meddling)
- Our Homunculi Are Different — Artificial Human
- Aura Vision — Stat-O-Vision
- Ban on Magic / Fantasy Gun Control — Nuclear Weapons Taboo
- Benevolent Mage Ruler / Sorcerous Overlord — Emperor Scientist
- Blue-Collar Warlock — Street Samurai / Corporate Samurai
- Centauroid Form — Tank-Tread Mecha
- Chainmail Bikini — Latex Spacesuit
- Changeling Tale — Alien Abduction
- Child Mage — Psychic Children
- Creating Life — Artificial Intelligence
- Creating Life Is Awesome — Benevolent A.I.
- Creating Life Is Bad — A.I. Is a Crapshoot
- Constructed World — A Long Time Ago, in a Galaxy Far, Far Away...
- Cool Airship — Cool Starship
- Dark Fantasy — Sci-Fi Horror
- Deity of Human Origin — The Singularity
- Dem Bones — SkeleBot 9000
- Demonic Possession — Puppeteer Parasite
- Doing In the Wizard — Doing in the Scientist
- Dream Walker — Digitized Hacker
- Dungeon Punk / Gothic Punk — Cyberpunk / Bio Punk
- Evil Sorcerer — Mad Scientist
- The Fair Folk — The Greys
- Fantastic Science — Fictional Field of Science
- Fantasy Aliens — Wizards from Outer Space
- Fantasy Counterpart Culture — Days of Future Past / Space Romans
- Fantasy Kitchen Sink — Sci-Fi Kitchen Sink / Conspiracy Kitchen Sink
- Fantasy Metals — Unobtainium
- Forced Sleep — Instant Sedation
- Functional Magic — Psychic Powers
- Gentleman Wizard — Gentleman and a Scholar
- Ghost Invasion — Alien Invasion
- Ghost Pirates — Space Pirates
- Ghostapo — Stupid Jetpack Hitler
- Golem — Robot
- Gorgeous Period Dress — Crystal Spires and Togas
- Heroic Fantasy / Low Fantasy — Planetary Romance
- High Fantasy — Space Opera
- Historical Fantasy — Alien Space Bats
- Instant Runes — Matrix Raining Code / Tron Lines
- Knight in Shining Armor — Space Marine
- The Legions of Hell — Mecha-Mooks
- Lilliputians — Nanomachines
- Mad Oracle — Mad Scientist / Mad Doctor
- Made of Magic — Energy Beings
- Mage Species — Differently Powered Individuals
- Magibabble — Technobabble
- Magic A Is Magic A — Minovsky Physics
- Magic Carpet — Hover Board
- The Magic Goes Away — Technology Erasure Event
- Magic Staff — Boom Stick
- Magical Eye — Electronic Eyes
- Magical Land — Inside a Computer System
- Magic is Evil — Science Is Bad
- Magitek / Magic-Powered Pseudoscience — Magic from Technology
- Mystical Plague — Synthetic Plague
- New Powers as the Plot Demands — New Rules as the Plot Demands
- No Such Thing as Wizard Jesus — No Such Thing as Space Jesus
- Not That Kind of Mage — Not That Kind of Doctor
- Occult Detective / Vampire Detective Series — Androids and Detectives
- Our Elves Are Different — Space Elves
- Our Monsters Are Weird — Starfish Aliens
- Parody Magic Spell — It Runs on Nonsensoleum
- Portable Hole — Pocket Dimension
- The Red Mage — Omnidisciplinary Scientist
- Salem Is Witch Country — Roswell That Ends Well
- The Sky Is an Ocean — Space Is an Ocean
- Standard Fantasy Setting — Standard Sci Fi Setting
- Soul Jar — Brain in a Jar / Brain Uploading
- Spirit Advisor — Virtual Ghost
- Spirit World — Cyberspace
- Sufficiently Analyzed Magic — Clarke's Third Law
- Telepathy — Electronic Telepathy
- The Dung Ages — Used Future
- The Undead — Cybernetics Eat Your Soul
- Urban Fantasy — 20 Minutes into the Future
- Weird West — Space Western / Cattle Punk / Desert Punk
- Wizard Duel — Dueling Hackers
- Wizard Workshop — Mad Scientist Laboratory
