<p>It is up to the professor to decide how many people he will let in. Usually if there are too many people signed up, there is a lottery. Sometimes for overenrolled classes additional sections are added to allow more people to take the class (this happened last year with “History of the Future” freshmen seminar and “Foundations” art class).</p>
<p>For some classes, however, the decisions are made in a different way - in some cases preference is given to majors or to upper classmen, since underclassmen will be able to take the class later. This particular class is very popular, and is often overenrolled, but as far as I know all the juniors and seniors that signed up are allowed to take it.</p>