Recent studies indicate that scientific research is part of prewriting in the scientific writing process. This article argues that since invention in scientific research is discovery of the unknown of the scientific community and invention in writing is discovery of ideas within existing knowledge, scientific research cannot be part of prewriting in the scientific writing process. Researchers should be aware that inventional heuristics introduced in freshman composition courses, which serve to discover ideas within existing knowledge, are not always applicable in real-life situations where scientific writing occurs, because the content of discourse is sometimes given in these situations.