The "weeder" course isn't intended to be symbolic. It tends to be a course that can only be offered after the students have gotten through the basic math cycle,

The "weeder" course isn't intended to be symbolic. It tends to be a course that can only be offered after the students have gotten through the basic math cycle, i.e., 3rd year, and is heavily mathematical / theory oriented. I taught it once as an adjunct -- Electrodynamics in the EE department. Teachers are fully aware that a "weeder" course is a problem, and make a sincere effort to get as many students through as possible. But nonetheless it results in a lot of attrition.