Once upon a time, down on the farm, ordinary lives had few options. Only a few neighbors were available as friends or lovers, only a few careers were possible, and most careers had rather predictable daily schedules. (Forager work varied only a bit more.) By contrast, cities, travel, and even war offered many exciting possibilities. Fiction celebrated these things, and fiction itself offered even more possibile experiences.

Our modern world is chock full of cities and travel, and many career and leisure options. Our diverse fiction celebrates this expansion of possibility. In fact, endless expanding possibility seems central to our modern view. We all “know” that new techs expand our possibilities, and an endless series of new techs lie ahead, each more unpredictable than the last. Science fiction emphasizes a blizzard of strange futures, from which most folks take the lesson that the future is so unpredictable that there is little point thinking about it. Most think we can’t even count on basic physics, as new paradigms could change everything.

But in the long run, this faith in endless possibility is completely wrong. Yes our dreamtime era is fantastically rich with change and possibility, but on cosmological time scales this simply cannot last. And not only is it possible for foresee outlines of the future, it is important that we do so.

Yes, our physics isn’t the last word, for but for most practical purposes it is damn close. New physics will only make a difference in incredibly unusual cases. Our understanding of basic economics is also hardly the last word, but we still understand enough for it to give useful insights into future societies.

Yes, new tech have recently given us each more options, but this is mainly because new tech tends to make us each richer. Wealth gives options. If our descendants are, as I suspect, much poorer than we, they may well have fewer options than us. And eventually economic growth and tech innovation must slow to a crawl. Our finite universe simply cannot continue our exponential growth rates for a million years. For trillions of years thereafter, possibilities will be known and fixed, and for each person rather limited.