In mentioning a transcendental field, I am adapting a term from the one book of Sartre that I sort of liked long ago, The Transcendence of the Ego (1936). Husserl had built his phenomenology on the supposition of a “transcendental Ego” — a foundational Subject that was to be free of the limitations of empirical subjectivity, and prior to any particular content. Despite this unpromising beginning, Husserl achieved some keen insights into details of the nature of appearance. Sartre wanted to adopt some of these results without the baggage of the transcendental Ego. (See also Husserlian and Existential Phenomenology.)
In transplanting this term to a more Kantian register, I want to suggest we should pause at the level of an ecosystem of transcendental Subjectivity-functions, without going on to assume that it must take the form of a single, strongly centralized Subject-entity. The idea is that every bit of transcendental content is already in itself a bit of Subjectivity (which is how I want to read “Substance is also Subject”), and any number of such bits that is more or less coherent may be taken as together constituting a subject. I then want to combine this with Brandom’s reading of the Kantian transcendental as linguistic/social/historical in nature and his identification of it with Hegelian Geist. (See also Psyche, Subjectivity.)
The Postmodern Peripatetic 