Btukfyl

Normally, technology in numerous fields will advance due to breakthroughs driven by a need for something like more efficient weapons or farming. How can I explain a civilization being "technologically stagnant" and having themselves stuck with technology found around the time ancient Rome existed (600 BC). I have theorized that they can't advance to using electricity due to solar flares constantly bombarding the planet, although I don't know if this is plausible. Also the world they live on is an Earth analog, although it has no fossil fuels present.

You've pretty much answered your own question insofar as if there is no need for technological advancement, there won't be any.

If your farms are producing all the food you need and the climate is consistent and temperate all year around, there are no barren areas, no strategic points of coastlines or ports that are envied by the rulers of opposing nations, no resource shortfalls...

...you get the picture...

Then there's no need to develop anything like better weapons, ploughs, or technology in general. Putting this another way, there is no reason to advance if your life is fine as it is.

This in point of fact leads to an interesting anthropological theory I once heard that said that technological advancement only happens in cold climates. The reason was that the cold made life uncomfortable, and provided a forced scarcity of food over a winter period. This meant that people strived to find ways to make their lives more comfortable and as such, developed and refined new ways of doing things and new tools to do them with.

Regardless of that theory, if you look at the relative technological level of European explorers and African tribes in the 18^th and 19^th centuries, it is clear that Europeans with their harsh winters and relatively scarce resources had advanced more than the African tribes with their temperate climates and a bountiful and relatively constant food supply.

So; make your civilisation relatively happy and content, and advancement won't be as fast as if they're struggling and uncomfortable.

I have a few thoughts on this based on groups on some historical context (and their modern philosophical descendants):

1. Groups which shun technology for religious reasons


2. Groups which cut themselves off from the outside world due to fear


3. Groups which fear technology itself and were it will take us in the future

Amish - religious angle

The Amish have definitely hit a stopping point when it comes to technological advancement. They've chosen to live simply in order to better serve their religion and idea of what it's god would wish. Indeed, this does not only limit technology use but limits the needed education (most stop school at 8th grade) that would be required to engineer new devices/tools.

Isolation or Fear of outside influence & loss of control

Now technological advancement (or at least economic advancement which can support such) requires periods of peace with access to rich cultures and resources (pgs.7-10). However, when pursuit of that peace causes such a fear of returning to war that governments start to impose heavy restrictions on its populace and actively force out any outside influence (pg.13) to ensure the power base of their own government - it tends to squash any ideas or technological development due to fear it will lead to revolutionary ideas or someone gaining a powerful "weapon"¹ the government does not control. It is basically trading growth for stability - at least until someone starts shooting cannons off your shore.

Fear of technology

There have always been those who prefer to live "off the grid" and those who fear what new technology will bring. One can look at Henry David Thoreau's Walden and the transcendentalist movement of the late 1880s and see elements of these ideas. While the Luddites of that same era - actually smashed new technology out of fear it would eliminate their livelihoods.

In modern times, we see the Neo-Luddist who range from the off-the-grid survivalist to calls for moderation - all the way to people still committing violence for fear of what technology will bring.

Or why not all three

It would not be hard to imagine a group which saw these driver-less cars coming (lets say Uber and Taxi drivers) starting a movement against this specific technology, began excluding countries and peoples who supported them. Then being expanded their philosophy to slowly include all technology as evil ("un-natural") and eventually take on religious undertones as justification for their fears.

^{1: Weapon here could be an actual weapon but also any form of new technology which allows you to generate income, food, or even good will at a rate that allows you to be a threat to those in power (whether you intend to us it or not)}

Pretty simple solution. Deny access to higher education. Or make it only for an elite group, several countries doing this right now. People can only work with what they actually know or have access to learning.

All ancient civilisations were essentially shaped by theology, so you simply need to make yours prohibit - and severely punish - technological advancement. I suggest you refer to the Safehold series by David Weber for an excellent example of how this could be achieved.