Stallybrass is saying that you should allow the thoughts of others to influence you as they naturally will, and attempting to create your own thoughts is useless.  He implies that you can only take the thoughts of others and put your own spin on them.

Stallybrass’s claim is somewhat valid when it comes to reseach.  Most of what I will do with my research project is take the information (thoughts) of others and refine them into my own conclusions.  However, Stallybrass significantly downplays the importance of the refining that I will do with other’s conclusions.  In fact, I argue that the way I interpret others thoughts has more weight than the thoughts of others.