So you hold to a syllogism that says if people thought there were specific things we would never be smart enough to understand, and it turned out they were wrong about those things, this principle by necessity extends now to everything? This is the fallacy of the excluded middle. More likely, there are things we didn't think we could understand, yet we did, and there are things we think we will understand, yet we won't. Often I observe a kind of "selective reasoning", where any time we understand something, it gets classified as science, and every time we don't, it gets classified as philosophy. This is quite convenient for allowing us to imagine that science can figure out anything (and philosophy, nothing), but it's really just a form of creative accounting.With respect, I totally reject the notion that there are aspects of nature that we are simply not smart enough to understand as non-sequitur.
That's what people said in Newton and Galileo's day too.