Human forms of feeling, objects of human attraction, our reactions constituted in art, are as universal and necessary, as revelatory of the world, as the forms of the laws of physics. This is the writer’s faith . . . — Stanley Cavell [The Senses of Walden, 102]
Cavell also announces that not only categories (like causality) but also — and this is a surprise — images carry the weight of the a priori :
our images . . . of dawn and day and night, of lower and higher, . . . of freezing and melting and moulting, of birds and squirrels and snakes and frogs, of houses and bodies of water and words, . . . are as a priori as our other forms of knowledge of the world.
Putting two and two together, it seems Cavell is willing to grant to Kant’s productive Imagination a power and authority in “world-shaping” no less active and legitimate than Kant’s Understanding in its exercise of authority in “world-shaping.” Understanding prepares us for knowledge of the world filtered by categories like causality. Kant grants a necessity to the categories like causality that underlie our grasp of the world that physics and the sciences and lawyers negotiate. Cavell will grant a necessity no less crucial than the necessity of “causality” — shall we call it aesthetic or poetic necessity? — to the images underlying our grasp of the world of artists immersed in their art, or of Thoreau immersed in his seeing a reflection of a Maker in the waters of Walden Pond. A moment of wonder-apprehension is delivered (when it is) as a moment of poetic [or poetic-religious] necessity held in Imagination; a moment of factual apprehension is delivered (when it is) as a moment of necessity held in the the storehouse of Knowledge.
If I follow, then the poet’s reality can be just as powerful and real as the physicist’s reality. Good news for a religiously poetic writer like Thoreau (and so many others).
 Cavell, Senses of Walden, 101.