You probably know this rhetorical canon primarily as "brainstorming," though I think it's broader than usual definitions of the strategies that encompass brainstorming.

Invention is a process of discovery: how can we find what we want to say? It is both creative and critical. As such, brainstorming and prewriting join research and reading—gathering—and a broader analysis of the rhetorical situation (purpose, kairos, audience, and a sense of the appropriate genre and its expectations) to go into the creation of arguments and writing.

You might think of invention as the big, messy mass of strategies and approaches that many writers use as they get to an early draft. We'll try out many different invention strategies this semester! Some of my favorites are freewriting and mapping.