Metaphysics and Epistemology are the two central pillars of philosophy, and they are deeply intertwined.
Metaphysics asks "What is real?" (Nature of Reality).
Epistemology asks "How do we know?" (Nature of Knowledge).
Relationship:
1. Epistemology precedes Metaphysics: Before we can claim to know what reality is, we must determine if our mind is capable of knowing it. (e.g., Kant argued we must critique reason before doing metaphysics).
2. Metaphysics influences Epistemology: Your view of reality shapes your theory of knowledge. If you believe only Matter is real (Metaphysics), you will likely rely on Senses (Empiricism). If you believe Reality is Ideal, you may rely on Reason (Rationalism).
3. Circular Dependence: You cannot define "Knowledge" without assuming some "Knower" and "Known" (Metaphysical entities), and you cannot define "Reality" without a way to know it (Epistemology).