Was Pure Science Necessary For Inventing a Steam Engine?

I had an interesting discussion on Twitter with the person who goes by the handle “Pseudoerasmus” and with David Wootton about the genesis of steam engine technology. I am thankful to both for taking the time and also for their patience with me. I have to confess some weaknesses here, I am not a physicist, and as I see in retrospect I got a few things wrong. Still I think my argument stands. It was not possible to make it in a succinct way on Twitter, so I will lay it out in this post.

The question at stake is whether you need “pure science” to invent a steam engine or not. If that was necessary, pure science must have played a crucial role in the development. That means it is hard to conceive how someone could have circumvented the pure science and still have developed a steam engine. In this case, it should be possible to show where the necessary input from pure science occurred.

If it was not necessary, there might still have been an input from pure science. But it should have been inessential. There would have to be some alternative way to develop a steam engine also without it. An even stronger claim would be that pure science did not play a role, which a forteriori also shows that it was not necessary. In what follows I will try to show this stronger claim. There is one point where there may have been an input from pure science. I am not convinced. But even if that was so, I will show why it was inessential for the whole development.