An open system is a system that has external interactions. Such interactions can take the form of information, energy, or material transfers into or out of the system boundary, depending on the discipline which defines the concept. An open system is contrasted with the concept of an isolated system which exchanges neither energy, matter, nor information with its environment. An open system is also known as a flow system. A viable open system exchanges energy, matter, and/or information with its surroundings through semi-permeable, regulated, or established boundaries that preserve identity while enabling adaptive flow.