Representationism, also known as representationalism, refers to the philosophical concept that reality is, in some way, represented or mediated by knowledge or perception. Synonyms for representationism include idealism, conceptualism, and mentalism, which all propose that our ideas or concepts of the world are the source of our understanding of reality. Another synonym is phenomenalism, which suggests that our perceptions of reality are the only things that can be known directly. Some philosophers also use the term constructivism to describe the concept of representationism, as it suggests that knowledge and reality are constructed through the interpretation of perceptions and concepts.