Good luck getting that printing press together without making any use of fire.
Stone tools to cut and shape the wood, carve the letters out of bone, dry your printing material in the sun. Ink can be made from vegetable dyes.
Along the lines of the printing press, I would say the written word is mankind’s greatest invention. Sort of a cop-out, I know, but hey…
Two more candidates:
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The assembly line.
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Beer. You don’t really think agriculture was invented so people would have grain handy to make bread, do you?
The invention of the “base 10”arabic numerical system.
This invention gave us the numerals we have today and eventually led to the Arabic invention of the “zero.” This allowed astronomical calculations to be made much easier than with Roman numerals, not to mention changing the face of education forever afterwards._
An interesting bit of trivia: Up until the end of the 18th century, Japan contibuted the least to mathematical development in the world. Why? Because they had a unique chartacter for each mathematical number. Imagine trying to remember each character to count up to 1,000,000. Impossible!
The edged tool-
aka Acheulian hand axe -
replacing sharp teeth and claws… predating the use of fire by hundreds of thousands of years, and not even invented by humans but our ancestors.
SF worldbuilding at
http://www.orionsarm.com/main.html
I’ll go with language.
But a lot of these things are “pick-up” inventions, aren’t they? Basically, found scattered on the ground?
The wheel. The axle is the real invention.
The axe.
Fire.
Language.
And even beer. 
Welcome to board, ArticCircle…you live in my town, and I can thus only speculate that your user name is wishful thinking about this time of year? 
There’s another thread on the board asking us to give our opinion on the most influential animal of all time. I will add to Zenster’s and E-Sabbath submission of Fire: the acceptance of animals into our life, i.e. the taming of dogs. It’s not an invention, of course, but it changed the world nonetheless.
Have I missed this, or has no-one mentioned the railroads? Many folks died while laying down those lines.
The condom.
Writing or currency probably.
Somebody go get James Burke, quick.
We need to determine here if we’re going to be looking at a single specific invention, or at the inventions that made that one possible.
Terry Pratchett wrote a few lines that can be usefully considered here. All you need is an axe and a way to make fire. That can get you a forge, and with a forge you can make simple tools, and with those you can make complex tools, and with those…
Nobody’s disputing your opinion. It’s just that, an opinion.
So, after three posts now, I think we’re pretty clear that you think fire is the most important invention, even though we technically didn’t invent fire, we just found a way to make it.
I’m surprised no one has mentioned clothing yet. Along with fire, clothing was responsible for mankind’s ability to exploit extreme environments, and provided a compelling reason to actively harvest the skin of the leopard, our natural enemy. Clothing also served as a medium for extensive personal adornment and class distinction, and the development of diverse textiles promoted trade both as utilitarian commodities and as luxury items. Although not quite as universally essential as the use of fire or bladed tools, clothing has been worn since the Stone Age in both the Old and New Worlds, and has been far more widespread than the printing press or the wheel. The accepted use of clothing in contemporary life also allows us to choose in advance whether to view someone naked, which I think most people would agree is a good thing. And without the sophisticated fabrics that the clothing industry has produced over the centuries, Muppets as we know them would have never evolved.
2trew - a James Burke fan ? all right !!!
And count me as someone who classifies FIRE as a human invention.
I believe Scientific American had an entire article on what they considered the #3 invention (they had classified fire and the wheel as **1 & 2 **respectively). They chose the bow and arrow for #3. (Unless someone wants to debate this should be TWO inventions).
Their reasoning was that the bow and arrow was a tool for a reliable food supply AND a VERY effective method for defense (and offense for that matter).
Personally, I’d side with Spevined and preidebt and say the plow should be #3.
As fire exists in nature, humans discovered fire. Humans did not invent it. Torches, matches, candles, etc. are inventions.
I dunno. If fire counts, then so should language. And language wins hands down as most important. It’s not even close. Language makes cooperation possible, and without cooperation, as a species we’re pretty much screwed.
Not beer
Refridgerators , to keep the beer cold
Declan
No one in their right mind is saying that humans invented fire.
I’m talking about the ability to make fire. The fire drill and use of flints changed the entire course of human existence. Watch the movie, Quest for Fire sometime. Before the ability to make fire came along, it required real ostiones to approach a burning forest or plain in order to extract some lit material.
I’ll restate how it is quite possible that without fire, humanity might never have survived. Fire came before domestication of animals or agriculture. Even knapped flints and spears did not match the survival benefits of having fire.
People were able to be productive at night, sterilize semi-rotted food prior to consumption, cook otherwise indigestible roots and nuts, temper wood spears and arrow shafts, ward off wild animals and most especially avoid freezing to death during winter. Being able to summon a profoundly life-giving force using such easily obtained components as a chunk of hardwood, a shaft, some rawhide lace, a bit of tinder and a bowed piece of wood was nothing short of miraculous.
Fire may not be an invention, but the making of it most certainly is.
A new device, method, or process developed from study and experimentation.
Definition of “invention.” Method and process - so the discovery of fire certainly qualifies, one must think.