  Phenomenology as a discipline is distinct from but related to other key disciplines in philosophy, such as ontology, epistemology, logic, and ethics. Phenomenology has been practiced in various guises for centuries, but it came into its own in the early 20th century in the works of Husserl, Heidegger, Sartre, Merleau-Ponty and others. Phenomenological issues of intentionality, consciousness, qualia, and first-person perspective have been prominent in recent philosophy of mind.