This page should be split because I'm getting some weird bugs partway down, at about the section titled, "On thickness".
Apparently, loading this page myself using Firefox 8.0 results in the problem you've mentioned, while IE 9.0 displays the page normally in its entirety. From this observation, my guess is that it could be a rendering issue.
That being said, the page is long enough that dividing the page still makes sense from a readability point of view regardless.