I'd go with a couple of ideas.
Passive defensive technology exists that quite nearly negates most attacks, including directed energy beams and projectiles with stupid amounts of KE and momentum.
There's offensive technology that can defeat it, but it's so expensive in comparison to the defensive stuff (either due to rare materials or complexity of manufacture), or possibly has components that are too fragile, that it's too expensive or fragile to throw away as projectiles. There might even be components that are too fragile to use as projectiles at all, whereas a soldier can put the fragile part in a backpack and have it attached to his melee weapon with a cable.
Thus, while there's some ranged weaponry, statistically it's ineffective enough that taking and holding ground from the enemy in a practical amount of time requires one side to get in close and beat/stab the crap out of the other side.
The defensive technology can be either advanced armor materials or shields of some sort, or a combination of the two, with "intertial compensators" or some sort, perhaps.
The offensive stuff could be either just advanced materials too, or be some sort of fields like a lightsaber, or again, a combination of both.
On the other hand, you can make melee
necessary if you're fighting an opponent that simply has insane numerical superiority.
Human wave attacks disappeared when machine guns and mines became prevalent because even the most populous real-world human nation cannot deal with the casualty rates.
But if you're dealing with some sort of aliens or robots or otherdimensional beings, it's possible that they can simply swamp you with dozens, or hundreds, or thousands, or even billions of troops, trying to get into melee, that eventually they WILL get there, no matter how susceptible they were to ranged weaponry.
Then again, if they had those kinds of numbers, it sounds like they'd beat the crap out of all your troops anyway, through numbers, once they get into melee range.
Btw, I'd throw out precognition.
Because if both parties had precognition, and it allowed two precognitive melee fighters to second-guess the other guy's second-guess in a neverending recursion until one guy's gives out and he gets hit, then as a rule they can do the
same thing to each other at a distance, with lasers or high-velocity projectiles.
Haruhi wrote:And science-fiction is a subtype of fantasy.
I disagree. There is a clear delineation between the criteria for a piece of fiction to qualify as science-fiction or fantasy. While a work can qualify as both, that's because it ticks the boxes two separate lists.. but it's still two separate lists. One is not a subset of the other.
If you don't believe that's the case, I'm not sure why you're bothering to explore this topic at all. Just use magic!
Haruhi wrote:Simon_Jester wrote:Works if there are no futuristic weapons such as lasers or hypervelocity mass drivers, and specifically if you want duels between speedsters.
If speed is achieved through manipulation of space-time, the speeders apparently could exceed the speed of light without violate the general theory of relativity.
If they can go that fast, then these individuals are essentially hypervelocity mass drivers, just by throwing random stuff really fast.
I'm guessing they'd also violate conservation of energy, but I won't go into that, because I'm already rather interested in the extent of your understanding of "the general theory of relativity".
Anyway, so basically this is a world of DC comic book Flash expies?
"..history has shown the best defense against heavy cavalry are pikemen, so aircraft should mount lances on their noses and fly in tight squares to fend off bombers". - RedImperator
"ha ha, raping puppies is FUN!" - Johonebesus
"It would just be Unicron with pew pew instead of nom nom". - Vendetta, explaining his justified disinterest in the idea of the movie Allspark affecting the Death Star