This issue of "definition" is missing what's at stake. The issue is modelling nature in such a way that plausibly includes subjective experience. And then validating this model. But subjective experience is intrinsically inaccessible to empirical validation. We can test the physical predictions of the model, but how subjective experience fits into the model is an orthogonal question. If we are to answer the question of subjective experience, we need to embrace "speculation" without empirical anchoring to guide our investigations. Shutting down speculation is just to shut down any investigation at all.