Invention: This common word takes on a whole new meaning in the context of rhetorical practice. You might imagine a scientist working in a lab or engineers working to develop the latest and greatest technological innovation. Rhetoricians, those who study and teach rhetoric, use the word to mean discovery, that is, ways of finding the best and most effective means of communicating. Invention includes generating topics for writing, studying and learning about those topics, undertaking library research and other kinds of inquiry, planning arguments and gathering evidence, experimenting with genre, and thinking carefully about audience. Invention in short, is the engine of all rhetorical practice.
Remember that collaboration is often a powerful means of invention. Sharing ideas, posing questions, challenging one another--these activities push and refine our thinking. For many of us, talking to people, whether in person or virutally, is essential to moving our writing forward.
The invention process of the hypothetical student writer in our earlier example includes coming up with a research question, looking into background materials about the issue at hand, researching for more specialized information, reading and evaluating the sources, reformulating ideas, perhaps by talking to peers and teachers, planning what sources to incorporate into the writing project, and deciding the most effective means of clearly and persuasively presenting research.
Given what we have said here, you would be right to conclude that rhetorical invention is a process of critical thinking and of learning.