That makes sense, and it's likely that if I read through the entire book that you linked to, I'd grasp it pretty clearly. But it was certainly out of my mental

That makes sense, and it's likely that if I read through the entire book that you linked to, I'd grasp it pretty clearly. But it was certainly out of my mental reach as an 18-year old. And believe me, I tried. In general, it appears that our ability to ask philosophical questions, especially of the mathematical variety, far outpaces our ability to find answers or even comprehend answers that others have come up with. It is highly plausible that this is linked to the disturbingly high occurrence of depression, bordering on mental illness, among mathematicians. (I know enough mathematicians personally for that observation to have some statistical validity, but anyone who has read many biographies of mathematicians should get the sense of it.) What I'm trying to say is that while many of the questions of mathematical philosophy pique our curiosity greatly, and it can certainly be a rewarding experience to get a taste of the beauty of the field, everyone should have a mental threshold for how much they are willing to get involved. Perhaps this is obvious to other people, but since it was a painful lesson for me, I feel obliged to share it :-)