A world similar to earth (climate fluctuations, the need to cook food), and because the natural atmosphere doesn't have oxygen, the intelligent organisms there don't breath oxygen. How far could a civilization go without fire, if at all? Is there an alternative to fire for heat and light? It doesn't have to be a single source, it could be two chemical reactions separately producing heat and light.
Stephen R. Donaldson wrote a series called The Gap Cycle which seriously discussed what a civilisation that used biological processing for all their needs, rather than the high energy density "hard" technology that humans rely on (all ultimately based on burning some form of fuel at some stage in the extraction/production process), would need to go through to produce equivalent products. As I recall the demonstrative example was making a tonne of steel; humans take a large quantity of iron ore mix with coke and flux light it on fire, pour it out, blow hot air through it and have finished metal of finely controlled quality within a few hours. We could mold, machine or forge a finished product the same day. The aliens would have to take that same ore, soak it in a vat of acids and/or enzymes (the character who was talking wasn't too clear) and then give the acid slurry and a carbon feedstock to a tailored bacteria to lay down the steel in a 3D printer type of arrangement. The finished product was slightly superior (no stresses caused by the item taking a pounding during production and it was truly a single homogeneous whole) but the process took weeks and while the energy input level was lower at any given stage the overall energy requirements were a lot higher, as were the material inputs. The aliens were quite keen to co-opt as many human ideas about material science as they could because humans were behind on territory but well ahead on the energy budget side of things.
I'd suggest that without fire a race of instinctual bioengineers could create heat, light, electricity, and even manage the reduction processing of metals (though depending on the atmosphere they live in they may not need to do more than shape existing reduced metallic deposits to their purposes) through any of a number of different biochemical and/or biomechanical pathways but everything would cost more (in terms of the embodied energy of a given object) and take longer.
I would think the odds of them never discovering fire would be vanishingly small though, most (possibly all) propellants and explosives are self oxidising mixtures or compounds, they burn regardless of the atmosphere they are in. As soon as they start to push into energetic chemistry fire is going to be a fun additional discovery.
Note we do have a number of existing examples of animals that use bioluminescence to create cold light, all endotherms create metabolic heat, bombardier beetles create enough chemical heat to vapourise water, and a number of creatures ranging from bacteria to insects, mollusks and even some fish are known to excrete pure reduced elements as a defensive adaptation to their toxic environment, a defense against predation or to allow them to feed more effectively. So life on Earth is certainly capable of creating some of the foundational materials we take for granted as part of our modern technological culture and probably much more with a little tinkering.
I don't think a fireless civilization could start.
Fire is useful because it gives its user some free energy to use. In principle there are exothermic reactions which do not involve open flames, for example the thermite reaction $2Al + Fe_2O_3 \rightarrow 2 Fe + Al_2O_3$, which could be used to release the heat needed in whatsoever process.
The problem is that all those reactions start with an element present in its reduced state, ready to be oxidized. Normally, as entropy goes, such an element would not be freely available for long times when exposed to the environment, and would need to be produced somehow.
With fire we are lucky because we get carbon "for free" thanks to the photosynthesis of other organisms, and with that and the oxygen in the atmosphere we can start the wheel, so to say, and accessing also the underground resources of other carbon-based and eventually also fissile materials.
One might also use geothermal heat or naturally occurring nuclear reactors as kickstarters, however such places are normally very limited in space and make the chances of success slimmer, and the related temperatures might not even be useful for some sort of progress.
Fire can be lit anywhere where there is wood or grass. One thing is to unintentionally throw some locally sourced copper ore or siliceous sand in a bonfire and notice it has changed after interaction with the heat, another thing is to carry it in the place where there is the heat source.
Fire isn't a 'start' of technology
Technology isn't bound by fire. Though many research stems from it, fire isn't the only tech tree.
We can already see many technologies that do not require fire to start. We have seen apes use impromptu spears. Something humans probably did as well. This can be enhanced without fire, like with adding a sharp stone point.
Architecture, agriculture and clothes all don't require fire. You can use all of this to create and improve, along with many other directions.
The missing of fire can be difficult in many areas, stifling the technology. That doesn't mean it can't thrive in other areas and that they can find ways around it. The lack of oxygen can even help with some sciences. Heating materials (solar power?) can give different results, as no oxidising reaction can start. So you can possibly mold or combine materials without getting an oxidation impurity. As an example, welding iron is best done without oxygen (though you need an alternative for the heat source).
Again, some areas might be stifled, but that by no means causes technology to not progress. Other heat sources will be discovered and used, as well as so much technology not requiring it.
This, is borderline impossible to answer with any degree of certainty, as the oxygen-less planet is just so fundamentally different from what we have, that any guesses are just that, guesses. But lets give us a chance and just simplify the core of the question and discard everything else.
What is fire. Fire is nothing more than the most simple way that we (early humans) have found to generate abundance of useful energy. Why did that help us?
At our earliest stages, it made us much more energy efficient. No longer did we have to waste chemical energy to keep warm (foraging and hunting all day to pay our warm blooded evolutionary bill). Cooking food, decreases the energy cost digestion, again saving us more chemical energy for more useful stuff. Even the earliest pottery, allowed us to store food longer, allowing us to not work for our food all the time as it took longer for the food to spoil.
As we advanced to future, most of our energy sources were also fire dependent. Burning coal, oil, natural gas, to produce heat and later steam are all part of the same process, we use combustion to change a latent energy of whatever to useful energy.
Gamechanger is electricity. It allows us to replace combustion. No longer do we go from latent chemical energy -(combustion)> heat -> useful, instead we do latent chemical energy -(electricity)> useful (be it heat, motion or both). Once you have a fire independent source of electricity, you can develop in whatever direction you wish.
So the question is, can we skip 10,000 years of combustion-based technological development and go straight to electricity? I think the answer is as simple as, do we have an alternative source of readily available energy, that allows us to advance enough to be able to transform other energy sources into electricity.
With difficulties and quite a bit of luck, yes as I see one viable source of readily available energy. Geothermal.
I am picturing a civilization starting around a fault line with stable volcanic activity. By shear luck, the volcanoes remain stable and active for a few millennia, to allow our people to go from stone age, to bronze age, to iron age. Fertile lands surrounding the ridge allow them to grow food surplus and form a scientific/philosophic class, who work on the further advancements. They are however locked to their fertile, energy abundant area.
Introducing iron age Nicola Tesla. He is fascinated with a rock, that attract iron flakes, and discovers, that sparks sometimes forms when he moves the rock through a sufficiently long coil of copper wire. He works on the theory of electromagnetism and gives birth to the first generators, which allow him to extract energy from the geothermal steam vents and later hydro-plants and wind-plants. Following which, the humanity is able to spread across the land, as the readily available source of energy is no longer just volcanoes, but any stream of water, or wind ridden valley. From this point on there is no limit to how far they can technologically evolve.
Not that much less plausible than "non-human advanced civilization." In the real world, we have no evidence of any kind of civilization-forming non-human intelligent life, fire-using or no. If you're supposing a race of intelligent aliens with an advanced civilization, you're already well into the realm of hypotheticals.
As for the interesting part of the question (how to make it plausible), that kind of has to be up to you. It's your story and world. One thing to keep in mind that fire is mainly useful as a source of heat and light. Light is useful on its own (assuming your aliens use sight as their primary sense), but there are other ways to get it even at the same "ground" level at which we started using fire - bioluminescence, natural chemiluminescence or phosphorescence/fluorescence (maybe some of their rocks are natural glow-in-the-dark things), handwavium crystals, etc. Show these aliens using some natural-looking glowy thing as a light source and your audience will make up an explanation for you that you can then pretend was your plan all along. Heat is mainly useful for (a) keeping certain kinds of organisms alive in cold environments (by way of reducing the internal energy they have to spend on maintaining homeostasis) and (b) speeding up chemical processes in various ways, either as a straightforward catalyst or by melting solid objects so you can mix them together. Both have workarounds. The first can be bypassed by just saying your alien species doesn't need to worry about freezing to death because of its alien biology. Implausible? Sure, but they're aliens so that ship sailed long ago. The second is really just a speed thing - as someone else mentioned, you can make the same reactions happen through other means, it just takes longer.
The real question is how they would develop things like metallurgy in the first place - there's some debate on precisely how we figured it out, but all of the explanations involve fire. The Gap Cycle-style bioengineered acid-refined metal-printing that Ash mentioned is a solid end state (not to mention extremely cool), but you need a lot of worldbuilding legwork to justify how they figured out bioengineering in the first place.
Alternatively, you could just slot in different sources for heat and light - various isotopes of handwavium crystals - and go from there. You can get a civilization started with cold-hammered metallurgy just fine, and once they figure out electricity they can run it through different arrangements of wires to get whatever combination of heat and light they need. Steel would be tricky, because it's a carbon alloy and the carbon usually comes from the coal you're burning to heat the iron, but there are certainly other ways to mix carbon in. Maybe there's a native organism that eats iron and carbon and extrudes a steel shell. Maybe "steel" is this dangerous but valuable stuff found only in the ruins of events too destructive for anyone to do on purpose. Maybe they just don't develop steel until much later, after they've developed things like electric arc furnaces or induction heating, when someone decides to add carbon to the mix and accidentally discovers a new super-metal. It's all up to you.
Heat, and thus fire, matters for most science and technology that we know so broadly neither trains nor tracks to run them on.
Still Asia, Europe and North Africa jogged along quite happily with horses and carts for millennia; no need there for fire.
Since neither sub-Saharan Africa nor the Americas had either, Great Zimbabwe might represent one limit. Does that help?
Without fire aren’t volcanoes, hot springs and hydrothermal vents valid sources of heat? All of those might limit the location but for laboratories and workshops, how might that matter?
Though the Munomutapa, and their wider Bantu family, used fire as did both Plains and Mesoamerican peoples, what says they had to? Could civilised creatures not eat fruit; work by daylight, phosphorescence and bio-electricity; live in warm climates?
Fire as a defence by night has been useful but who says it was necessary here, or must be on a built world?
That the Plains peoples of North America saw “living in cities” as anathema, I mention solely because it raises the secondary question: Is this about “pure” civilisation, or do cultures without cities also count?
The Mongol hordes that Genghis Khan and his descendants led to overcome much of Europe and China and all of India were by definition uncivilised but didn't they also, by definition through outcome, have one of the strongest cultures ever seen?
They might have eaten fruit, if it grew on the Steppes… and they might have treated their cattle as the Masai of modern Kenya did; sometimes still do: drinking not only the milk but also the blood and having opened veins to leach out that blood, also slicing flesh from a living beast before allowing the beast to heal in time for the next harvest.
If cultures count, what about the North American Plains people, the South Sea islanders, the Maori of modern New Zealand or the Inuit of the far north? Do Australian Aborigines have a place here?
To help define the parameters of the original Question, I suggest two more:
How will a world with no oxygen compare to the many already seen in science fiction whose creatures breathe other gasses or live under water? Does the difference here reach slightly sideways or in every sense, stretch worlds away?
How are the lack of oxygen and (how much) similarity to Earth the only important details? There’s no need to follow my style, and I would have started by imagining the civilisation I needed, then working back to who built it, before considering what they breathed - unless there was an over-riding reason for another approach…
I got your alternative right here!
Incandescent bulbs produce light and heat via the ohmic heating to incandescence of a durable filament. The filament does not burn up because it is in a vacuum.
You can also produce electric light using a tube of low pressure gas - a neon light is an example. You can produce heat by using a resistance wire, like in a space heater.
No fire is involved, just electricity.
Look at the downvotes. The pain! And all because of assumptions. That is ok. I will bring you all along. Especially you, @Ash.
The OP said nothing about primitives and there is no requirement that these advanced people developed everything solo. The OP wants an advanced civilization with heat and light and no fire. Just about all tech innovations are given or sold from the inventors to the new users. Iron for example was invented in one place and then spread over the world.
So too your advanced civilization. Another people came along and sold them stuff. The nonoxygen breathers are not stupid. They figured it out. Now they are advanced: they have induction furnaces and smelt metal and make glass and they have generators and all that stuff.