There are several answers, of course. The Bible suggests that there was already a weapons user, or abuser, in the first human generation, in fact, the first born human: Cain, who slew his younger brother Abel. (The scriptures are silent on how exactly Cain did it, so maybe he didn’t use a weapon at all and just strangled the guy).
If you’re diffident about the creationist approach, we can offer you the fruits of science today. While no one is completely sure when the first Neanderthal bashed a peer’s ridged brow in with a rock, archaeologists had, until recently, evidence that projectile weapons like spears and arrows were invented twice, once about 60,000 years ago and again some ten or twenty thousand years later, after the technology died out once. But now they have new evidence that we’ve been spearing one another, and our now-extinct Neanderthal rivals, since about 71,000 years ago.
The (UK) Independent reports:
The fine stone blades were excavated from a prehistoric site called Pinnacle Point on the southern coast of South Africa and are between 6,000 and 11,000 years older than the previous oldest known samples of spear and arrow blades, scientists said.
The discovery suggests that the invention of lethal projectile weapons came far earlier in the course of human prehistory than previously realised and that, once invented, the knowledge was passed down the generations, according to a study in Nature led by Curtis Marean of Arizona State University.
Previously, scholars thought that the technology of “projectile weapons” was first invented about 60,000 years ago and then lost for many thousands of years before being reinvented between 40,000 and 50,000 years ago.“
Every time we excavate a new site in coastal South Africa with advanced field techniques, we discover new and surprising results that push back in time the evidence for uniquely human behaviours,” Dr Marean said.
Arrows and spears were probably the key weapons that allowed anatomically modern Homo sapiens to migrate out of Africa and successfully colonise other parts of the world, including Europe where the Neanderthals lived, he said.
“When Africans left Africa and entered Neanderthal territory they had projectiles with greater killing reach and these early moderns probably also had higher levels of hyper-cooperative behaviour,” he said.
“These two traits were a knockout punch. Combine them, as modern humans did and still do, and no prey or competitor is safe. This probably laid the foundation for the expansion out of Africa of modern humans and the extinction of many prey as well as our sister species such as Neanderthals.”
Of course, some Neanderthal genes and traits survive today in modern humans, thanks to ancient interspecies uggle-dee-boo. But if you look at what Dr Marean says were the advantages that allowed our ancestors to vanquish those Neanderthals, you see the same traits that make elements, units, and nations victorious today: superior projectile weapons with greater kliling reach (think of our essay on range here) and superior organized, cooperative behavior.
If only Abel had had weapons, and someone to team up with, the whole Book of Genesis might have gone a different way. Instead, he’s a dead end, like the Neanderthal.
One last thought: just because a weapon is superseded by new technology doesn’t mean it goes away. Many news stories have noted that American homicides are statistically more likely to involve blunt-trauma weapons (like Ogg’s rock up there) than “assault weapons, ” and that even Cain’s stranglin’ thumbs remain viable as lethal weapons millennia later. That’s why, while some combatants only master the latest lethal technology, whether it’s a sniper rifle or an F-22, true warriors apply the warrior spirit to any weapon that comes to hand, and failing any weapon at all, hands themselves.
Einstein’s famous observation that he didn’t know what weapons would be used in World War III, but “World War IV will be fought with sticks and stones,” was facile, but false in this: we never stopped fighting with sticks and stones. New weapons are additional, not in lieu of old favorites.