# Does a large population make sense in a galactic society with automation tech?

So I am writing a Sci-Fi novel where humans are currently spread out over 440 Star systems ( ~ 2000 Light years). There has been several breakthroughs in Automation technology and all manual labor jobs are done by bots. Humans are only needed to supervise and work in certain service industries (Therapy, Writing, Acting etc..)

So I am having a hard time justifying a large population. In fact, my calculations are currently giving me less than 1 billion people. What would people do in such a society? Does a large population even make sense? ( Large meaning in billions)

I thought about having a large military (Occasional conflicts with aliens) but even that would not require billions of humans.

PS: There is no FTL travel, Only FTL communications. There are Stargates (Discovered from ruins) which are used to go from system to system.

Edit: The people do not really need to work to survive. Agriculture is fully automated and can easily meet the demand. If a family is just trying to meet basic needs then one person probably only needs to work once a week ( One person in a 4 member family). Yet there are things like spaceships which are very expensive and would need decades of income for an average person (For the cheapest shuttle). Real estate varies by location. Real estate on a space station is vastly more expensive than a planet.

• Out of curiosity, and to calibrate your calculations, given today's technology here on Earth, how much population do you calucate Earth needs? I suspect your calculation is incredibly conservative, doesn't take into account the fact that tech is never universally available, and that there are always members of the population who are non-contributing (children, the aged, the disabled, etc.). In the end, if you want a large population, you need to craft the world to fit, not craft the world, and then wonder how to justify an aberration.
– JBH
Dec 24, 2018 at 4:05
• Are you sure you did your math correctly? In 2009, there were 20.5 million active duty military (estimated) world-wide against 6.8 billion people. That's 0.3%. That suggests you have a vanishingly small military. But, more to the point, the structure of a society is much more complex than a multiplier applied to the military.
– JBH
Dec 24, 2018 at 5:04
• The support & administrative staff attached to the military services has been continually expanding over time. The fighting force component continues to shrink. If this trend continues, tiny armies, the actual fighting troops, will be surrounded by huge echelons of supporting personnel. Dec 24, 2018 at 6:20
• 440 star systems would mean 2.27 million per star system. That isn't a lot if you think about it. The population of New York City, the 10th most populated city on the planet has 18.6 million people. If we're to assume more than one planet potentially per star system, this becomes even more reasonable still. Not sure I understand the rationale behind needing to ensure it is realistic.
– Neil
Dec 24, 2018 at 8:19
• Human societies don't decide upon a goal (standard of living, economy, employment, culture, etc) and then grow/shrink their population to achieve it. Those aren't really goals at all - they are actually just measures of what the population is doing with their time. Robots might do lots of manual labor, but there's lots of other kinds of work to be done. Dec 24, 2018 at 15:07

Your large population could exist without justification, if your story needed it.

Consider retired persons. There are millions of them in the developed world. There is no particular need for them - they are living because they were born, grew old and did not die. Many help younger members of their families, but otherwise they spend their time with hobbies, socializing, watching sports and other such leisure pursuits.

If you want a big population in your post-scarcity society, you could model it along those lines. It sounds pretty nice, actually.

• Yeah I understand. I just find it awkward to be so spread out and still have less than a billion people. Especially since we have 7 billion now just on Earth. Dec 24, 2018 at 3:26

Your population will depend on your society's view on family and children, and economic conditions which help or hinder having a family and raising children.

If most work is automated, how will people earn what they need to survive or be comfortable? Are people poor because there's no work and they're dependent on government handouts? Are people rich because they're living on trust funds established by ancestors generations ago?

If people are safe, free, comfortable, possessed of ample living space, and they have cultural values which promote families, they'll have children. If they can spend all day at home with their families, they might have four or six children instead of two or one. That could increase your population.

Like another poster mentioned, older people living longer will increase population, and also lower infant mortality rates will increase population. Advanced medical technology could allow people to live active productive lives much longer than in reality, and it could increase fertility.

Colony world governments could incentivize having children to build up the labor force. Tax breaks, bonus payments, land grants and social rewards could all contribute to a higher birthrate over time.

it would depend on the society structure.

Does it make sense to justify all of those people in a purely capitalistic society? Yes and No.

• Yes, The service industry litterally explodes as humans having copious amounts of free time work 2-days a week and have 5-days a week of social time in restaurants, theaters, theme-parks, etc...
• No, every job is a standardish 40-50 hour work week. The excess labour is consistently on social security and the political landscape collapses as the population actively revolts and impedes commerce even dismantling the automation.

The essential feature is to provide income for everyone to live off comfortably or ensure that those people are too focused on surviving to care that the rich have unlimited production or are incapable of mounting a significant threat to that production.

A society may make this a given. The automation is the peoples property and everyone gets a portion of the production as their right. Some of the production is directed toward state activities etc. Those who wish to provide non-automated services may work in the hopes of acquiring time-shares of the automated production. These would include acting, politics, teaching, etc... The worker might only work 1 day a week or for 1 week in every five. People wishing to use these services would pay a portion of the time-shared production to them. Products could be done similarly by allowing the inventor to receive a portion of the production time-shares spent by an individual in acquiring that specific product.

Alternately society may manufacture meaningless work to force everyone into a job. The society can certainly afford this as the high-levels of automation ensure that the state does not have to play nice with the people.

Another society may in fact leave 99.9999% of people in subsistence life-styles with all of that automation going to the rich/state.

• "...standardish 40-50 hour work week." There's no particular reason that should be "standardish". Work weeks have been reducing in the developed world for quite some time: the American average is 33 hours, Netherlands 27, France 30, Germany 25.6. There have been arguments for reducing it to 21 hours, to a four-day work week, to going as low as 15 hours for office workers (analysis that shows desk workers are only productive 3 hours per day). By the time society has spread out to other star systems, a single 8 hour workday in a week, except for certain professions, could very well be the norm. Dec 24, 2018 at 18:48
• @Keith Morrison I know there is no "standard" work week ever. But considering that there are 168 hours in a week, and 56 of those are needed (roughly) for sleep, that leaves 112 hours for living and working. Splitting that equal gives 56 which are 8 hours days 7 days a week. Also those averages are (generally) over the whole of society (unless you can point out the specific surveys) so that does include many stay at homes, students, homeless, and those who choose to work reduced hours for health or other reasons. My point was a society could favour a small core of workers, excluding others. Dec 26, 2018 at 22:57

The way to a large population is simple, and it even happened before on earth.

Earth's baby boom was in part the soldiers returning home from ww2, but another factor that people overlook is the increase in living standards that people had also led to a higher birthrate for a good time after the war even with widespread birth control. If your peoples are wealthy, have high living standards, lots of space and short work hours, they will get bored fast and start reproducing. It does not make sense for their to be a low pop if you have your people living high on the hog and not having a lot to do, as supervising a drone system should not take all day unless something goes really wrong.

The large population might well by a hindrance rather than something that needs justification. There are too many people than there are jobs, but only because nobody has figured out a way to cut the population down.

In this case, all that automation is required to support the population, not the other way around. The majority of people might be unemployed, but surviving off some form of welfare.

Perhaps the government has tried to reduce population growth, but failed. There could have been schemes like China's one child policy that have failed, and so society is forced to bear the burden of all these unnecessary people.

I would expect plenty of social and economic issues as a result.

This situation lends itself well to any number of dystopian futures. See the Earth in the Expanse for an example of one.

As two other answers mentioned, retired people and large families could lead to a large population, automated labour or not. And you mentioned manual labor is automated, but with the possibility of large families, you could reason there need to be educated individuals or unions to educate the children and do administrative work. We're talking several stages of education: primary school, high school, various universities, etc.

Then as for retired people, you need medical personnel who would care for them - doctors for diagnostics, controlling therapy and such.

Another reason could be that your colony is something of a resort or haven for education, or something that would incentivize people to move to this particular colony. If it's a resort, there is administration, real-estate work and so on. Lots of coordination.