Erasmus wrote that “every definition is dangerous.” His abhorrence for the sharp definition was due to a fear of dogmatism. I’m no Erasmus but I’d say, “let’s risk it.” Experience tells me that weak definitions can do even more damage. Our vague defining leads to misunderstandings and undermines sound decision making. If you aren’t sure what “balanced literacy” or “science of reading” mean, how can you deliver –- or avoid delivering — the appropriate pedagogy?    In education, we don’t define...