Thought

• 1. Introduction

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  Thought, in its most ordinary meaning, is the cognitive activity that runs without any direct input from the senses. You can weigh an idea, judge whether a claim is true, or picture your grandmother, all while sitting perfectly still. The eyes and ears go quiet, yet something keeps working. The word itself carries this inwardness. It comes from the Old English thoht, from the stem of thencan, meaning to conceive in the mind, to consider. But naming the activity does not explain it. What actually happens when the soul, as some have put it, talks to itself? Is thinking a kind of silent speech, a parade of images, or a quiet machine shuffling symbols? Can an animal do it, or a computer? And why has a single word been stretched to mean both the act of thinking and the beliefs and ideas left behind once the thinking is done? The pages that follow trace how philosophers and psychologists have tried to pin down something that, by its nature, hides from view.

• 2. What Counts As Thought

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  In its most common sense, thought names conscious processes that occur independently of direct sensory input. Considering an idea, evaluating a proposition, or making a judgement all qualify. Under this usage memory and imagination count as forms of thought, while perception does not. The word narrows and widens depending on who is using it. A tighter sense reserves thought for the most typical conscious, conceptual, or linguistic operations: judging, inferring, problem-solving, and deliberating. A wider sense throws the doors open to every mental process, conscious or unconscious. In that broad Cartesian usage, where the mind is called a thinking thing, thought becomes nearly synonymous with mind itself. The cognitive sciences often adopt this expansive reading. The literature frequently sets thinking against feeling. On this contrast, thinking is rational and dispassionate, while feeling carries direct emotional engagement. A second ambiguity haunts the term. Thought can mean the process, but it can also mean the product: the beliefs, mental states, or systems of ideas held by a person or shared across a group. Academic discussions often leave it implicit which sense is meant, and that quiet slippage shapes how the next set of theories disagree.

• 3. The Classic Theories

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  Platonism casts thinking as a spiritual activity in which the mind perceives and examines Platonic forms and their relationships. These forms are universals in a changeless, non-physical realm: goodness, beauty, unity, sameness. The hard part is separating beauty itself from mere beautiful objects. Plato met the obvious objection, how we reach a realm we never enter, with his theory of recollection: the soul knew the forms before birth and can remember them. Modern philosophy rarely accepts the metaphysics this requires. Aristotelianism keeps its feet on the ground. The mind thinks about a tree by instantiating tree-ness, not in matter but in the mind, the same essence in both places. Universals here exist only insofar as they are instantiated, and the mind reaches them through abstraction from experience. Conceptualism sits close by, holding that thinking consists in mentally evoking concepts, most of them abstracted from sensory experience, a few perhaps innate. Both face a sharp objection. To think that it will either rain or snow, evoking the concepts of rain and snow is not enough. The disjunction, the or that binds them, goes uncaptured. Associationism, rooted in empiricism, offers a different picture: thinking is a succession of ideas governed by laws of association rather than logic. By similarity, contrast, and contiguity, one idea summons the next. But the chain need not be rational. Because cold links to Idaho, the thought this coffee shop is cold might slide into the thought Russia should annex Idaho. Imagism, one version, runs thought as a sequence of images, which stumbles on the things we can think but cannot picture, such as infinities in mathematics.

• 4. Thinking As Language

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  Inner speech theory, sometimes called psychological nominalism, holds that thinking consists of silently evoking words and stringing them into mental sentences. Awareness of one's own thoughts becomes a kind of overhearing of a private monologue. The view ties three features together: inner speech resembles hearing sounds, it uses language, and it forms a motor plan that could drive actual speech. Evidence helps it along, since thinking is often accompanied by muscle activity in the speech organs, activity that may assist thought without being required for it. Daydreaming gives critics their counterexample, a candidate for non-linguistic thought. The stakes reach the animal mind: if thought must be linguistic, only humans qualify; if not, the gap shrinks. Jerry Fodor introduced a sharper version, the language of thought hypothesis, naming the medium Mentalese. He defines a linguistic structure precisely. It needs atomic and compound representations, where each compound is built from others or from atoms, and where the meaning of a compound depends on the meanings of its parts. Fodor argues this is the best explanation of productivity: from few atoms, a system generates infinitely many representations, and human beings entertain an infinite number of distinct thoughts despite limited mental capacities. Systematicity and inferential coherence round out his case. Objections come from neural networks, which produce intelligent behavior without representational systems, and from mental representations that seem to run non-linguistically, as maps or images. Computationalists prized the hypothesis because operations that respect syntax and semantics, like an inference by modus ponens, can be carried out by physical systems through causal relations, and the same logical system can run on brains or computers alike.

• 5. The Machine Analogy

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  Computationalist theories, common in the cognitive sciences, understand thinking as a form of information processing. They rose with computers in the second part of the 20th century, when theorists saw thinking by analogy to computer operations: storage, transmission, and processing of information, encoded differently in the brain but in principle the same. The dominant definition leans on the Turing machine, capable of executing any algorithm from a few basic moves, reading a symbol from a cell, writing one to a cell, acting on what it reads. From these it can run deductive reasoning by the rules of formal logic and simulate language processing, decision making, and motor control. Computationalism makes the strong claim that thinking just is computation, that the mind is a Turing machine. Theorists split it two ways. Functionalist approaches define mental states by their causal roles, allowing both external and internal events, so a thought is whatever plays a certain part in producing further internal states and verbal outputs. Representationalism instead defines thoughts as sequences of intentional mental states, and pairs naturally with the language of thought hypothesis, reading those sequences as symbols ordered by syntactic rules. The objections cut deep. In one sense the theory seems trivial, since almost any physical system can be read as computing. The molecular movements in an ordinary wall have been described as isomorphic to the formal structure of a program, which would absurdly make the wall a thinker. A second objection grants that computation captures some aspects of thought but denies it can account for other crucial aspects of human cognition.

• 6. The Kinds Of Thinking

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  A judgment evokes a proposition and then affirms or denies it, deciding what to believe and aiming at truth or falsity. The traditional combination theory says judgments combine concepts, so judging that all men are mortal joins man and mortal. Franz Brentano offered a rival: every judgment is belief or disbelief in the existence of some entity, leaving only two fundamental forms, A exists and A does not exist. He stressed the gap between merely representing a content, called entertaining a proposition, and affirming or denying it. The grammar tracks the difference, since thinking that usually carries a judgment while thinking about names the neutral representation, as when one thinks about a grandmother with no proposition at all. Reasoning draws conclusions from premises or evidence. Deductive reasoning follows rules of inference that guarantee the conclusion if the premises hold, as all men are mortal and Socrates is a man yield that Socrates is mortal. Non-deductive reasoning, also called defeasible or non-monotonic, stays compelling without guaranteeing truth: induction concludes the sun will rise tomorrow from all the previous days, alongside inference to the best explanation and analogical reasoning. Fallacies break these norms. Denying the antecedent is a formal fallacy: if Othello is a bachelor then he is male, Othello is not a bachelor, therefore he is not male. Informal fallacies trade on ambiguous or vague language, as feathers are light, what is light cannot be dark, therefore feathers cannot be dark. Underneath all of this lie concepts, the general notions that sort objects into classes. You can only think about a proposition if you possess its concepts; without the concept wombat, the sentence wombats are animals can be read but not entertained. Concept formation acquires new concepts by learning the features shared across instances and the ability to identify positive and negative cases, often by learning the associated word, sometimes aided by metaphor.

• 7. Solving And Deciding

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  Problem solving aims at a predefined goal by overcoming obstacles, and it leans on two motions of mind: divergent thinking, which generates as many alternative solutions as possible, and convergent thinking, which narrows them to the most promising. Researchers chart steps along the way: recognizing the problem, understanding its nature, fixing the criteria a solution must meet, prioritizing those criteria, monitoring progress, and evaluating results. The type of problem matters. Well-structured problems make the steps clear though hard to execute, like long multiplication, an algorithm that guarantees success if applied correctly. Ill-structured problems leave the steps unclear, with no formula, and the answer may arrive in a flash of insight, the problem suddenly seen anew. Heuristics, by contrast, are rough rules-of-thumb that bring the thinker closer without guaranteeing success, such as working forward or working backward when planning a trip. Fixating on one course of action becomes its own obstacle. Experts and novices diverge here: experts spend more time conceptualizing the problem and build more complex representations, while novices rush to execute putative solutions. Deliberation turns thinking toward action. It formulates possible courses of action and weighs the reasons for and against each, using foresight to anticipate what might happen. Decisions compare alternatives and choose the most favorable. Decision theory models the ideal rational agent, who always selects the alternative with the highest expected value, the sum of each outcome's value multiplied by its probability. One tradition compares this whole inner process to the trial-and-error of animals facing a new problem, with one crucial difference: the trials run inwardly as simulation, so only the winning behavior need ever be carried out.

• 8. Below The Surface

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  Episodic memory relives past events, a form of mental time travel that re-experiences rather than copies, adding a feeling of familiarity and chronological placement absent from the original. It aims to represent how things actually were. Imagination, by contrast, presents objects without claiming how things are or were, and that missing link to actuality buys freedom: its contents can be varied, changed, and recombined into arrangements never experienced before. Both arise without sensory stimulation yet stay closer to sensation than abstract thought, since they present contents that could in principle be perceived. Unconscious thought runs further from view, in the background, unexperienced and never observed directly. Its existence is inferred. Faced with a hard decision, a person may fail to solve it, then later find the solution suddenly flashing before them with no conscious steps taken in between, a cognitive transition that seems to demand an unconscious thought to explain it. Some theorists go further, claiming conscious thought excels at simple problems with few variables but is outperformed by unconscious thought on complex problems with many variables, since conscious attention holds only a limited number of items at once. Others reject that superiority. The proposed contrasts persist: conscious thought tends to follow formal logical laws, while unconscious thought leans on associative processing, and only conscious thinking is conceptually articulated and runs through the medium of language. Psychoanalysis sharpened this hidden territory. In Sigmund Freud's structural model, the psychic apparatus splits into the id, holding uncoordinated instinctual trends, the ego, the organized realistic part, and the super-ego, the critical, moralizing function. For psychoanalysis the unconscious holds not everything outside awareness but what is actively repressed, a force known only by its effects, expressing itself in the symptom. Carl Jung went wider still with the collective unconscious, a reservoir of the experiences of our species, shared across a people or all humanity, holding concepts like science, religion, and morality. Jung traced the idea to the representations collectives coined by Lucien Levy-Bruhl in his 1910 book How Natives Think; Freud did not accept a collective unconscious.

  Cognitive phenomenology asks what it feels like to think. A much-cited thought experiment sets two people before a radio broadcast in French, one who understands it and one who does not. Both hear the same sounds, yet only the first has the accompanying thought that matches the meaning, which argues for a distinctive cognitive character beyond the sensory. Phenomenologists also contrast empty intentions, which present an object abstractly without sensory content, with intuitive intentions that present it through the senses. Searching for one's glasses, the empty intention of them lying on the kitchen table is intuitively fulfilled when one sees them there, so a perception can confirm or refute a thought. Metaphysics takes up the mind-body problem: how conscious experiences can arise from gray matter endowed with nothing but electrochemical properties, and how beliefs and desires can make neurons fire and muscles contract correctly. These puzzles have confronted philosophers at least since Rene Descartes. The embodied cognition approach, drawing on Heidegger, Piaget, Vygotsky, Merleau-Ponty, and the pragmatist John Dewey, claims the mind, the embodied agent's actions, and the environment form one whole, so analyzing the mind alone can never dissolve the problem. Psychology turns thought into an object of experiment. Cognitivism grew from the Gestalt psychology of Max Wertheimer, Wolfgang Kohler, and Kurt Koffka, and from Jean Piaget, who traced cognitive development from the sensorimotor stage of the first two years through concrete operations to formal operations on abstract principles. Neo-Piagetian theories ground that development in increasing speed of processing, enhanced cognitive control, and increasing working memory. Positive psychology adds another angle: in Character Strengths and Virtues, Peterson and Seligman catalogue positive characteristics, encouraging thought that builds on a person's strengths rather than fixing their symptoms, a thread that runs straight into the study of optimism and positive thinking.

  The laws of thought traditionally name three principles of logic: the law of contradiction, the law of excluded middle, and the principle of identity. Their acceptance is wide but not universal. Aristotle held the law of excluded middle false for uncertain future events, judging it currently neither true nor false that there will be a naval battle tomorrow. Modern intuitionist logic also rejects it, tying mathematical truth to proof, and Godel's incompleteness theorems show that unprovable cases exist in every sufficiently strong formal system. Dialetheists reject the law of contradiction, holding some propositions both true and false to escape paradoxes like the liar's paradox and Russell's paradox, though they must then dodge the principle of explosion, that anything follows from a contradiction. Some add a fourth, the principle of sufficient reason, that everything has a sufficient reason, ground, or cause, though it sits awkwardly as a metaphysical principle among logical ones. Counterfactual thinking represents what is contrary to the facts, answering What if questions. Thinking after an accident that one would be dead without the seatbelt changes a few facts while holding the rest in place. People engage in it more after something bad follows their own action, producing many regrets; these upward counterfactuals feel unpleasant, while downward counterfactuals, imagining something worse, carry positive emotion. Thought experiments lean on exactly this counterfactual reasoning, setting up imaginary situations to learn what follows. John Searle's Chinese room puts a person who does not know Chinese inside a closed room with a giant rule book for replying to messages, arguing that neither the person nor a computer truly understands. Critical thinking holds itself to standards of clarity and rationality, running meta-cognitive checks that the reasoning is sound and the evidence reliable, drawing on both formal and informal logic. John Dewey's example has a thinker watching foam bubbles move contrary to expectation, then modifying the situation to test rival explanations, which following an algorithm blindly or accepting a sudden flash of insight would not match. Positive thinking, an important topic in positive psychology, withdraws attention from the negative and aligns closely with optimism. Studies suggest a correlation with well-being, as students and pregnant women with a positive outlook handle stress better and recover faster from surgery. Yet its benefits depend on other factors: optimism can backfire when events lie outside the agent's control, and it can decay into unrealistic fantasy, while pessimism may soften disappointment by anticipating failure. In the New Thought movement, positive thinking appears in the law of attraction, the pseudoscientific claim that positive thoughts can directly attract positive outcomes from the external world.