No fire, but what instead?

Question

It has been noted by many that dolphins don’t have fire and any marine animal would have trouble developing technology. But we need fire on Earth. What if fire was not a thing, but something else allowed manipulation over the materials in the environment beyond what mere animals can do?

In this post I speculated on life in a superdense gas that would seem similar to a liquid in terms of being able to move through it, perhaps even is a supercritical fluid which has low viscosity and is compressible like a gas and has properties variously like gas or liquid. (Thanks to ArborianSerpent for the inspiring question. The inclusion of the ↭ is a complete coincedence as I did not notice his username until just now!)

Considering what oxgenated supercritical water is used for, I think that in general this atmosphere, being at a super-high pressure, will not be very reactive. So flame and fire using air as one of the reactents will not be a thing on this world.

Now I described these beings as tool users and hunter-gatherers. I already know how mermaids would “cook” and I was careful to say that meat was “prepared” for eating and animal materials could be “cured” or “preserved” for tools and materials use, without saying how.

So why does everyone say that technological development needs fire? What limits will they run into if they don’t have an effective and safe way to work with high temperatures? I suppose chemical reactions can geneate high temperatures which they learn to work with once they already have some level of technology.

Why do they need fire? Is there something present in their environment that can take its place? Is fire just a specific example of this enabling thing, the details of which can vary from planet to planet with radically different environments?

Answer 1

Fire was an important early technology because its something almost all living things fear. Given how weak humans are, being able to generate fire was a major step towards protecting ourselves in a primal world.

Cooking with fire tends to kill bacteria + organisms, so you'd have more deaths from food without a complete replacement (or diet alteration).

I think a lot of the chemicals and reactants we would use to replace fire rely on goods created with fire (glass) in order to store them. I'm not sure if natural glass products created by volcanoes and such would be able to store similar chemicals, but its probably possible. These things don't tend to be very abundant on our planet though, so you're talking about replacing something cheap (fire) with a more precious and likely less renewable option.

Smelting was mentioned as something that requires fire. That assumes your culture is going to use metals. Raymond E. Feist's Riftwar series had a world almost completely devoid of metals that functioned with treated woods that were around the same hardness as metals. Very hard bones would also be an acceptable substitute.

In books I've read, the main alternatives to metal-based tech are either magic or biological. You could "grow" a computer on a wooden circuit board if you possessed an organism capable of processing inputs in the same fashion as a computer processor.

I suppose another replacement option for dolphins might be undersea magma vents (above the ocean, active volcanoes?). You might be able to engineer a process to work in/near one of those to generate the temperatures you need to cook things, smelt metals or whatnot.

Answer 2

Fire is incredibly useful. As humans we've invented too many uses to count. However a few of the highlights include: climate control, cooking, sanitization, metalworking, protection, warfare, transportation and combustion engines. There are workarounds for some of these such as using electricity to cook, fuse metals together, or using radiation to sanitize.

Not having fire means that if you want an advanced society you need to have a different path through history. The main reason is that early advancements like firing clay, basic copper and bronze tools, and the invention of better ceramics for transporting and preserving goods require heat.

Without the ability to use fire, your society must use some other heat source. Cooking, metalworking, firing clay, and things of that nature don't require fire specifically, they require heat. It just happens to be that fire was the most readily available form of heat to humans.

Another barrier to advanced civilizations is that to get the ability to automate things using computers, wiring, and even basic electricity you need a source of heat. Without it there's no way to reach advanced technology.

However, all is not lost. Fire might be the simplest, cheapest, most readily available source of heat here on earth, but on a world of gas that would probably be chemical reactions. Exothermic chemical reactions release heat and there are lots of sources for them. Throwing combustion aside for now, neutralization is probably the easiest. This is the reaction that occurs between an acid and a base. Using strong acids and bases you can achieve a portable heat source all you have to do is mix them together and poof heat. Another workaround for creating a lot of heat (enough for metalworking and everything else) is a thermite reaction using iron oxide and aluminum you can get temperatures of up to 2500 °C (iron's melting point is 1538 °C). Thermite does require some heat to get it up to its reaction temperature but using other chemical reactions you could achieve this.

Answer 3

While chemical reactions can allow for welding and cooking, there is one thing they cannot do. Smelting. Sure, using reactions we can connect veins, but if we want to mold the metal into sword or axes, fire is the best solution available by a massive margin.