Any sufficiently advanced technology is indistinguishable from magic. – Clarke's Third Law
Corollary: Everything magical can be achieved with sufficiently advanced technology.
Most fantasy I've seen takes the stance that "magic just is and people are born able to use it". Some of it applies real-world physical laws or posits science-like processes, and some of it doesn't, but magic's always just there as an independent entity. That's fine by me. I enjoy those stories. I don't think magic itself can be done any other way.
However, can we replicate it? Can we, in a science-rich, magic-poor world, create the effects and creatures we associate with fantasy? (Or, can we create magic-poor fantasy worlds where all the "magic" is advanced science? A kind of blend between sword-and-sorcery and cyberpunk?*)
- Transformation spells: We'd need a way to quickly and efficiently alter bodies or objects. I suggest nanotech keyed to genetics and/or morphological qualities. Easiest way to initiate the "spell" would be injection, though I'm sure we could find a way to make ingesting a "potion" a better option.
- Location spells: It's going to be tricky to find a distant person with technology, assuming tracking devices aren't an option. The simplest method I can think of is locking onto a DNA signature or the personalized vibration of atoms in a human body.
- Premonitions and prophecies: This'll involve a form of time travel or access to information from either alternate time streams or time waves.** We'd get this with a) supercomputers b) lab-based evolution c) brain implants.
- Hybrid creatures: Obviously, highly-advanced gene splicing. How else are we ever getting a gryphon?
More ideas, anyone?
* I should be fair and point out that there is fantasy out there that already does this, to a degree. The Artemis Fowl and WebMage series, for starters.
** Not exactly mutually exclusive.