For all the posts implying that people who came up with the concepts of phlogiston and elan vital were just using science without the benefit of today's education is missing the point.
Today's scientists come up with ideas like string theory or dark energy, but they don't stop there: they are frantically trying to find evidence for them and so far failing. So they are just neat ideas that might explain a lot if shown to be true,, but not much more than that. General relativity goes on providing evidence supporting it, including the new evidence for "frame dragging".
Phlogiston and elan vital were ideas that died for the LACK of evidence. The discoveries of oxygen and electrochemistry killed them. However, when the ideas were proposed, if you didn't know the answer, you left it there or made something up. I might mention also caloric, which was a pure guess based on very little but quashed by science in the form of experiments whose results fitted the concepts of energy much better.