Okay, looking back, I was kind of vague on what the vital force actually is in my original post.
Yes, it's what makes the difference between living and non-living things, but that's not the whole story.
One of the things that Vitalism leads to is the prediction that Spontaneous Generation occurs.
Well, before the last few hundred years, people didn't understand a lot about the world. One of the things they didn't have a good grasp on was why food goes bad.
Leave out meat and maggots appear, or mold or rats.
People used to think that these things were spontaneously generated out of the air.
Which is fair enough for people who couldn't observe things on a microscopic level, like fly eggs or mold spores, but not so much when it comes to the rats. I'm not inclined to be kind when it comes to those.
This probably sounds absolutely ridiculous, especially about the rats, but this is a thing that people genuinely believed for a rather long time.
It was supposed that the vital force is present in the air, and when exposed to dead matter (such as meat) life forms would appear spontaneously and fully formed.
It seems obvious to us that this doesn't make sense, that life has to come from life via reproduction, but things like the reproduction cycles of insects and fungi weren't fully understood at that point. This was a time where it wasn't fully understood that what a mother saw during pregnancy or conception wouldn't impact on the appearence of a child (but we'll get to that another time).
On the subject of biogenesis (life from life) it's important to draw a distinction between spontaneous generation and abiogenesis.
Abiogenesis is the name given by science to describe the origins of life in the first place. The development of biological reactions and molecules from simpler non-biological chemicals. It's a complicated process that's not fully understood by science, but we do have a number of details worked out. From what we know, it's definitely possible, even if we can't fully describe it yet.
Unlike spontaneous generation, abiogenesis does not require some nearly undetectable force in the air and it doesn't create complicated life forms such as maggots, mold and rats.
I'm bringing this up because on a superficial level, these two things do sound similar.
Another reason for bringing it up is because some people try to poopoo the idea of abiogenesis by comparing it to spontaneous generation, so it is important to make the distinction clear.
So, according to vitalism, there is a vital force in the air that can react with certain things and make complex life forms appear like magic. What is this exactly?
One interpretation is the breath of god.
Yeah, sounds super cool doesn't it?
This one is derived from the god of the bible. According to Genesis, he breathed the breath of life into Adam (and possibly Eve too, it's a touch contradictory on this front, but we can cover that another time).
This is partially what leads us to interpret the god of the old testament to be a wind god. Yes, there's some sun god stuff in there (particularly when you take into account the new testament) but we're more concerned with the wind god aspect.
The Christian and Jewish god is generally believed to be omnipresent, and wind does that a heck of a lot better than the sun does.
As a quick experiment, wave your hand around in the air. You can feel the air molecules brush against you skin, so you can see why a wind god would have a more compelling claim to be omnipresent than a sun god would. Clearly a sun god isn't, I'm writing this after the sun has set, after all.
So, when combined with the idea of vitalism, we have the notion of a god that imbues everything with life by his mere presence.
With this all in mind, how can this help your worldbuilding?
Well, as with the phlogiston, it's all about creating a world that is superficially similar, but fundamentally different.
The natural fit for vitalism, spontaneous generation and the breath of god, is fantasy fiction, but I do think that any kind of spec fic could use these concepts. It would make a very interesting twist for the reader.
If twists aren't your hing, then if you do have an omnipresent god in your world, you could very effectively use spontaneous generation to show that. You could also use it to demonstrate the absence of such a god if that is part of your story.
This is just one suggestion of what you can do with these concepts, the sky is the limit when it comes to how these ideas can be exected in your world.