Thought
In their most common sense, thought and thinking refer to cognitive processes that occur independently of direct sensory stimulation. Core forms include judging, reasoning, concept formation, problem solving, and deliberation. Other processes, such as entertaining an idea, memory, or imagination, are also frequently considered types of thought. Unlike perception, these activities can occur without immediate input from the sensory organs. In a broader sense, any mental event—including perception and unconscious processes—may be described as a form of thought. The term can also denote not the process itself, but the resulting mental states or systems of ideas.
A variety of theories attempt to explain the nature of thinking. Platonism holds that thought involves discerning eternal forms and their interrelations, distinguishing these pure entities from their imperfect sensory imitations. Aristotelianism interprets thinking as instantiating the universal essence of an object within the mind, derived from sense experience rather than a changeless realm. Conceptualism, closely related to Aristotelianism, identifies thinking with the mental evocation of concepts. Inner speech theories suggest that thought takes the form of silent verbal expression, sometimes in a natural language and sometimes in a specialized "mental language," or Mentalese, as proposed by the language of thought hypothesis. Associationism views thought as the succession of ideas governed by laws of association, while behaviorism reduces thinking to behavioral dispositions that generate intelligent actions in response to stimuli. More recently, computationalism compares thought to information processing, storage, and transmission in computers.
Different types of thinking are recognized in philosophy and psychology. Judgement involves affirming or denying a proposition; reasoning draws conclusions from premises or evidence. Both depend on concepts acquired through concept formation. Problem solving aims at achieving specific goals by overcoming obstacles, while deliberation evaluates possible courses of action before selecting one. Episodic memory and imagination internally represent objects or events, either as faithful reproductions or novel rearrangements. Unconscious thought refers to mental activity that occurs without conscious awareness and is sometimes invoked to explain solutions reached without deliberate effort.
The study of thought spans many disciplines. Phenomenology examines the subjective experience of thinking, while metaphysics addresses how mental processes relate to matter in a naturalistic framework. Cognitive psychology treats thought as information processing, whereas developmental psychology explores its growth from infancy to adulthood. Psychoanalysis emphasizes unconscious processes, and fields such as linguistics, neuroscience, artificial intelligence, biology, and sociology also investigate different aspects of thought. Related concepts include the classical laws of thought, counterfactual thinking, thought experiments, critical thinking, and positive thinking.
Definition
The terms "thought" and "thinking" are used in different ways in psychology and philosophy. In their most common sense, they refer to conscious processes that occur independently of direct sensory input. This includes activities such as considering an idea, evaluating a preposition, or making a judgement. In this sense, memory and imagination count as forms of thought, while perception does not. In a narrower sense, only the most typical cases are called thought-specifically conscious, conceptual or linguistic processes such as judging, inferring, problem-solving, and deliberating. Sometimes, however, the terms are understood in a much broader sense to include all mental processes, conscious or unconscious. In this wide usage, they can be treated as synonymous with mind, as in the Cartesian tradition and in the cognitive sciences. Some accounts further add that only processes leading to intelligent behavior should count as thought. A common contrast in the literature is drawn between thinking and feeling. In this distinction, thinking is seen as a rational, dispassionate activity, while feeling involves direct emotional engagement.The words thought and thinking can also refer to the results of these processes, such as beliefs, mental states, or systems of ideas held by an individual or shared within a group. Academic discussions often leave implicit which of these senses is intended.
The word thought derives from Old English þoht or geþoht, from the stem of ''þencan.
Theories of thinking
Many different theories of thinking have been developed. They attempt to describe the main features and processes involved in thinking. These theories are not necessarily mutually exclusive, meaning that some of them can be combined without contradiction.Platonism
According to Platonism, thinking is a spiritual activity in which the mind perceives and examines Platonic forms and their relationships. This process is described as a kind of silent inner dialogue, where the soul "talks to itself." Platonic forms are understood as universals that exist in a changeless, non-physical realm, distinct from the sensory world. Examples include the forms of goodness, beauty, unity, and sameness. The challenge of thinking, in this view, lies in recognizing and distinguishing these true forms from the imperfect copies and imitations found in the physical world. For instance, one must separate the idea of beauty itself from mere beautiful objects. A central difficulty for this theory is explaining how humans can think about or learn these transcendent forms if they exist in a different realm. Plato addresses this issue with his theory of recollection, which claims that the soul was once in direct contact with the forms before birth and can therefore "remember" them. However, this solution relies on metaphysical assumptions that are not widely accepted in modern philosophy.Aristotelianism and conceptualism
According to Aristotelianism, the mind thinks about an object by instantiating its essence. For example, when thinking about trees, the mind instantiates "tree-ness." Unlike actual trees, this instantiation does not occur in matter but in the mind, though the universal essence is the same in both cases. In contrast with Platonism, universals are not seen as timeless forms existing in a separate intelligible realm. Instead, they exist only insofar as they are instantiated. The mind comes to recognize universals through abstraction from experience, a view that avoids some objections directed against Platonism.Conceptualism is closely related. It holds that thinking consists in mentally evoking concepts. While some concepts may be innate, most are acquired through abstraction from sensory experience before they can be used in thought.
Critics argue that both theories face difficulties. One problem is explaining the logical structure of thought. For instance, to think that it will either rain or snow, it is not enough to instantiate the essences of rain and snow or to evoke the relevant concepts. The disjunctive relation between them is not captured in this way. Another challenge lies in providing a clear account of how the mind acquires essences or concepts through abstraction.
Inner speech theory
Inner speech theories hold that thinking is a form of inner speech. This position, sometimes called psychological nominalism, maintains that thinking consists of silently evoking words and connecting them to form mental sentences. A person's awareness of their own thoughts is explained as a kind of overhearing of one's silent monologue. Three central features are often associated with inner speech: it is in some sense similar to hearing sounds, it involves the use of language, and it constitutes a motor plan that could be used for actual speech. The link between thinking and language is supported by evidence that thinking is often accompanied by muscle activity in the speech organs. Such activity may facilitate thought in certain cases but is not required for thinking in general. Some versions of the theory propose that thinking does not occur in ordinary languages like English or French but in a specialized symbolic system with its own syntax. This is known as the language of thought hypothesis.Inner speech theory has strong intuitive appeal since introspection suggests that many thoughts are accompanied by inner speech. Critics argue, however, that not all forms of thinking are linguistic. Daydreaming, for example, has been cited as a case of non-linguistic thought. This debate is significant for the question of whether animals can think. If thinking necessarily depends on language, then there is a sharp divide between humans and other animals, since only humans possess sufficiently complex languages. But if non-linguistic thought exists, then this gap may be smaller, suggesting that some animals are capable of thought as well.
Language of thought hypothesis
There are various theories about the relation between language and thought. One prominent version in contemporary philosophy is called the language of thought hypothesis. It states that thinking happens in the medium of a mental language. This language, often referred to as Mentalese, is similar to regular languages in various respects: it is composed of words that are connected to each other in syntactic ways to form sentences. This claim does not merely rest on an intuitive analogy between language and thought. Instead, it provides a clear definition of the features a representational system has to embody in order to have a linguistic structure. On the level of syntax, the representational system has to possess two types of representations: atomic and compound representations. Atomic representations are basic whereas compound representations are constituted either by other compound representations or by atomic representations. On the level of semantics, the semantic content or the meaning of the compound representations should depend on the semantic contents of its constituents. A representational system is linguistically structured if it fulfills these two requirements.The language of thought hypothesis states that the same is true for thinking in general. This would mean that thought is composed of certain atomic representational constituents that can be combined as described above. Apart from this abstract characterization, no further concrete claims are made about how human thought is implemented by the brain or which other similarities to natural language it has. The language of thought hypothesis was first introduced by Jerry Fodor. He argues in favor of this claim by holding that it constitutes the best explanation of the characteristic features of thinking. One of these features is productivity: a system of representations is productive if it can generate an infinite number of unique representations based on a low number of atomic representations. This applies to thought since human beings are capable of entertaining an infinite number of distinct thoughts even though their mental capacities are quite limited. Other characteristic features of thinking include systematicity and inferential coherence. Fodor argues that the language of thought hypothesis is true as it explains how thought can have these features and because there is no good alternative explanation. Some arguments against the language of thought hypothesis are based on neural networks, which are able to produce intelligent behavior without depending on representational systems. Other objections focus on the idea that some mental representations happen non-linguistically, for example, in the form of maps or images.
Computationalists have been especially interested in the language of thought hypothesis since it provides ways to close the gap between thought in the human brain and computational processes implemented by computers. The reason for this is that processes over representations that respect syntax and semantics, like inferences according to the modus ponens, can be implemented by physical systems using causal relations. The same linguistic systems may be implemented through different material systems, like brains or computers. In this way, computers can think.