Am I understanding skepticism?

I'm not sure if I really got the concept that Mason was trying to deconstruct in Chapter 5. He said he was going to look at the notion "that anything--or rather anything important--be can be beyond understanding." He then outlines what philosophical skepticism is, saying it's "the view that there are many things that, in practical terms, I do not or cannot understand. The barrier to understanding lies in the makeup of the human mind." But then he adds the slightly mocking example, "Just as I am not smart enough for superstring theory and too lazy to learn Finnish, so my mind may not be fitted to achieve certainty."

Unlike Mason (I think--everything I write in these blog posts should go with the caveat that I could be grossly misinterpreting the text), I believe that it's possible to have things be beyond understanding without saying that things are inherently unintelligible (a view I think we rejected on Tuesday) or that minds are weak enough that certain concepts are beyond us. Here's my thinking:

It's pretty much given that we don't understand everything. ('We' can mean either an individual or society as a whole.) However, we reject the idea that ideas that could be understood are inherently unintelligible--everything can be understood, though it must be placed in the correct background. So I place the reason that we don't understand everything somewhere in the human mind--but not where Mason does. He seems to present this view as saying that human minds are incapable of understanding certain ideas, which looks to me like the same kind of argument for unintelligibility--I don't think there's a concept a human mind can't comprehend, it just needs the right background to do so (which could indeed be near-impossible to achieve, but the point is that it shouldn't be entirely impossible.) So where are the limits?

I think we can also assume that, while human minds don't have this threshold of being able to understand certain things but not other things, human minds don't have unlimited abilities--that is, they can't do everything at once. Understanding is (most of the time) not instantaneous; it takes time. And that's where the big limit is. Could humans understand all there is to understand in an infinite amount of time? I don't see why not, given the bases this argument rests on. But it's not like I'm too lazy to understand Finnish and that's why I don't know Finnish (or substitute whatever-ancient-text that we haven't figured out how to translate), I'm just trying to understand other things in the limited time I have to do such things.