the positive aspects of one's situation and is intimately related to optimism. Definition The terms "thought" and "thinking" refer to a wide variety of psychological activities. In their most common sense, they are understood as conscious processes that can happen independently of sensory stimulation. This includes various different mental processes, like considering an idea or proposition or judging it to be true. In this sense, memory and imagination are forms of thought but perception is not. In a more restricted sense, only the most paradigmatic cases are considered thought. These involve conscious processes that are conceptual or linguistic and sufficiently abstract, like judging, inferring, problem solving, and deliberating. Sometimes the terms "thought" and "thinking" are understood in a very wide sense as referring to any form of mental process, conscious or unconscious. In this sense, they may be used synonymously with the term "mind". This usage is encountered, for example, in the Cartesian tradition, where minds are understood as thinking things, and in the cognitive sciences. But this sense may include the restriction that such processes have to lead to intelligent behavior to be considered thought. A contrast sometimes found in the academic literature is that between thinking and feeling. In this context, thinking is associated with a sober, dispassionate, and rational approach to its topic while feeling involves a direct emotional engagement. The terms "thought" and "thinking" can also be used to refer not to the mental processes themselves but to mental states or systems of ideas brought about by these processes. In this sense, they are often synonymous with the term "belief" and its cognates and may refer to the mental states which either belong to an individual or are common among a certain group of people. Discussions of thought in the academic literature often leave it implicit which sense of the term they have in mind. The word thought comes from Old English þoht, or geþoht, from the stem of þencan "to conceive of in the mind, consider". Theories of thinking Various theories of thinking have been proposed. They aim to capture the characteristic features of thinking. The theories listed here are not exclusive: it may be possible to combine some without leading to a contradiction. Platonism According to Platonism, thinking is a spiritual activity in which Platonic forms and their interrelations are discerned and inspected. This activity is understood as a form of silent inner speech