Heidegger says, “human comportment is tuned throughout by the openedness of beings as a whole” (GA 9: 193/147, translation modified).
So, the first thing to say is that our disclosure of essences is not an explicit grasp of what the essence is, nor is it a particular experience or comportment with a particular entity. “Addressing something as something,” Heidegger notes, “does not yet necessarily entail comprehending in its essence whatever is thus addressed. The understanding of being (logos in a quite broad sense) that guides and illuminates in advance all comportment toward beings is neither a grasping of being as such, nor is it a conceptual comprehending of what is thus grasped” (GA 9: 132/104). Heidegger illustrates this point: “we are acquainted with the ‘essence’ of the things surrounding us – house, tree, bird, road, vehicle, man, etc. – and yet we have no knowledge of the essence. For we immediately land in the uncertain, shifting, controversial, and groundless, when we attempt to determine more closely, and above all try to ground in its determinateness, what is certainly though still indeterminately ‘known’: namely, house-ness, treeness, bird-ness, humanness” (GA 45: 81). As a result, “the essence of things,” Heidegger notes, is ordinarily something “which we know and yet do not know” (GA 45: 81). The essence is “not first captured in a ‘definition’ and made available for knowledge” (here, Heidegger is speaking specifically of the essence of truth; GA 45: 115). This is because, as he explains, the knowledge of essences is originally manifest in the way “that all acting and creating, all thinking and speaking, all founding and proceeding were determined by and thoroughly in accord with the unconcealment of beings as something ungrasped” (GA 45: 115).
We can say, then, that the disclosure of being consists in our being disposed in a particular way for the world. An understanding of being is concealed when it is not operative in our experience of the things in the world. What distinguishes each historical age from another, Heidegger claims, is that each has a different style of “productive seeing,” of perceiving things in advance in such a way that they are allowed to stand out as essentially structured (see GA 45, section 24).
We can illustrate this by going back to the gold example above. The fight between medieval and modern conceptions of gold is based ultimately in different ways of picking out salient entities in the world – that is, different ways of responding to some evident property or properties that they possess. One way of being disposed might lead us to find the true being of a thing in the extent to which it approaches God by being like Him. Another way of being disposed might lead us to find the true being of a thing in its ability to be turned into a resource, flexibly and efficiently on call for use. When someone disposed to the world in the first way uncovers a lump of gold, and subsequently defines gold as such and such a kind of thing, what she takes to be an essential property will be driven by her background sense that what is most essential in everything is its nearness to God. When someone disposed