The student, though, is seldom aware of this, primarily because he's never told what they are, he's never exposed to philosophical thinking and his teachers are often ignorant of those assumptions as well. Every specialised science at the least assumes that its own subject matter has a distinct existence. In the methodology they follow, every specialised science also reveals assumptions about how that subject matter relates to the subject matter of other disciplines. In our study this term we will be doing what amounts to the metaphysics of ethics. This is the branch of philosophy that is concerned with the theory of knowledge.
Any epistemological theory has metaphysical assumptions behind it.
Knowledge is always characterised in terms of what is taken to be real. Because every specialised science relies upon methodologies of investigation for acquiring knowledge of its subject matter, every specialised science also has epistemological assumptions operating behind it.