Read another response by Douglas Burnham
According to Heidegger philosophy has never really asked what we mean by "Being". According to him we ask what the essence of this or that form of being is but we never concern ourselves with being proper. Perhaps what Heidegger means or alludes to in this question is the idea that the very fact of being is in some way the very essence of being. This reminds me of Fichte's idea of the fact of consciousness rather than a principle of consciousness as the starting point of philosophy. And yet this fact of being just like the fact of consciousness is mysterious and elusive, while paradoxically present, and hence suppressed by a reductive urge within philosophy. Yet, I'm kind of skeptical about Heidegger claim of a suppression within philosophy of the question of being. It seems as if the question of being was first made problematic far further in the German tradition than Heidegger, as early as Kant, if its not something that has always been with philosophy. Kant argued very much like Heidegger, I think, that it was impossible to know being through thought but that there were non-cognitive means of apprehending being. So is Heidegger really bringing an innovative question that has been suppressed by philosophy?