Stallybrass means that one’s thoughts should be reactions to the thoughts of (or facts presented by) others. What we believe and all that we think is a reflection of the world we live in; whether it be real life, reading or some other influence, our thoughts stem from experience.
The relevance of this idea to our research is essentially that our research question should not merely be something we dream up on our own (and it seems impossible for this to be the case), but rather a reflection of and reaction to all we have learned about a subject. Our research questions and the way they are shaped will depend upon how we interpret, understand, and believe in the ideas of others. The origin of a research question is not just the researcher him/herself, but instead is derived from external influences which have interested or shaped a questioner in some way.