Wittgenstein's rule-following argument draws considerable attention: its policy significance for education , very little. Confronted with rule deviation, what justifies claims to 'sound"/"unsound" implementation of curricular reforms, or reasonable adaptation? Playing on John Mighton's Possible Worlds scenario, I probe these questions on different planes of inquiry through similar vignettes, focused on his ethically aimed math training program (JUMP). Surveying the topic space, I first touch on fervent debate between Rorty and his critics, Putnam and McDowell , over 'solidarity" grounding judgment. Must 'soundness' claims be "answerable to the world," and if so, how do we justify our educational practices ? Is sharing a 'sense"/'sensibility" (a fact/value) of "pedagogic soundness' sufficient to uphold its veracity? I then explore the controversy between contending paradigms of discovery learning and Mighton's guided training in math fundamentals, illustrating opposition between liberal-analytic definitions of teaching with training . In terms of student diversity, which possible worlds beckon account? Finally, drawing on Medina , we see the problem of encountering alien practices through the lens of "logical insanity." Faced with seemingly "unsound" reforms, teacher resistance acts as healthy, conservative brakes; alternately, recalcitrance can normatively blind teachers to innovation, effectively stalling improvement in learning . Not an either/or in terms of grounding, balance is advocated between the need for (a) faithful immersion in demonstrative practices in order to understand (immanently) their sense within the flow of classroom life; and, (b) the professional need for reasons or warrants—liberal-analytic , rational justification motivating the exertion of energy needed to sustain change initiatives.