If one's understanding of _part_ of a system increases to enable manipulation of that part of the system, but one's ignorance of the effects of that change in the broader system remains, meaning that the increase in understanding has led to an increase in unexpected effects in the broader system, has one's overall understanding increased, or decreased?
Not sure if that's too abstract, but your statement that "the world has been significantly less predictable since the Enlightenment" made me wonder, because you'd think "less predictable" means that understanding has gone down.
I would draw a sharp distinction between 'understanding' and 'predictability'. Understanding is about our knowledge of and ability to manipulate the world. Predictability is our ability to reliably forecast the future of the social world.
Of course our understanding has increased. But that has generated rapid and accelerating changes in society and a monumental increase in its complexity, which together, make it significantly harder to predict the future of the social world.
I am not saying that we don't have a better predictive grasp of the natural world. We obviously do.
Not sure if that's too abstract, but your statement that "the world has been significantly less predictable since the Enlightenment" made me wonder, because you'd think "less predictable" means that understanding has gone down.