If post-qualitative studies is committed to rethinking epistemologies and ontologies of matter and humanism, then why is the field perpetuating narrow, "one-slit," theorizing? Does it matter who we theorize with? And what matter matters in post-qualitative inquiry? These questions guide the discussion in this essay as Pillow offers a critique of how post-qualitative inquiry thought with narrow interpretations of new feminist materialism is limiting itself theoretically resulting in epistemological ignorance and ontological whiteouts. After a review of what is at stake, Pillow provides a brief introduction to quantum theory and the famous double-slit experiment suggesting that by ignoring their own ontological whiteouts "new" feminist materialisms and post-qualitative studies are reproducing colonial "one-slit" theorizing. Pillow concludes by discussing how ethico-onto-epistemic response-ability--theoretically and in praxis--is necessary to whatever post-post times we are in. This is a response-ability that refuses "one-slit" theorizing and enters into inquiry with entangled ensembles and decolonial attitude.