Distinctive theories, often referred to as 'ISMS', are philosophical and ideological beliefs that have been developed over time. These theories are typically based on the ideas of a particular individual or group, and they can be used to explain and interpret the world around us. Examples of ISMS include Marxism, capitalism, and existentialism. Each of these theories has its own unique set of principles and beliefs, which can be used to explain and understand the world in different ways.