My goal in this paper is nothing less than to make philosophical sense of the term “transcendental” as it is used in twentieth-century philosophy. I want to do this by constructing a notion of philosophical reductionism which not only defines the term “transcendental” but also renders explicit the idealistic theses implicit in transcendental philosophies. While I intend an ideal construction of the notions “transcendental” and “idealism,” I think that the notions I develop apply to the philosophies of Husserl, Merleau-Ponty, and (...) Heidegger. The historical locus of the paper is Husserl’s transcendental phenomenology, but later sections of the paper will show that the primary concern is not simply to offer a reinterpretation of Husserl but to make intelligible the very notions of “transcendental subjectivity” and “idealism.” Readers who find that their philosophical questions are answered by claims that the world is constituted in transcendental intersubjectivity and that “There is no world without an Existence that sustains its structure” will not share the urgency this writer feels to attain a modicum of clarity. (shrink)