We thought phlogiston was a thing, so someone invented chemistry
Chemistry is a fairly new science, invented in the 1770s. You could argue it only happened because one scientist was annoyed at a flimsy theory that attempted to explain a whole lot of everything.
According to MEL Science, Johann Joachim Becher was the first to come up with a theoretical substance he called terra pinguis. George Ernst Stahl gave it a name that became more popular — phlogiston — but it was essentially burning. The theory said this substance was contained in all things that burned and was released by the process of burning. Things that burn easily had a lot of phlogiston, and when it was gone, burning stopped. When the air absorbed too much of the substance it became phlogisticated and wouldn’t allow anything else to burn.
Sounds reasonable enough, right? The theory stood for about a century, until French scientist Antoine-Laurent Lavoisier decided to call bullgiston. He was the first to really sit down and have a long chat with phlogiston about all the reactions it couldn’t explain, and decided to come up with his own theories of combustion that actually worked. The American Chemical Society credits him with being the first to describe oxygen and for laying out a series of guidelines for the new science of chemistry, all so something like this phlogiston nonsense wouldn’t happen again and delay knowledge another century or so.