Philosophy Language of Thought
Murat Aydede
  • LAST REVIEWED: 18 November 2022
  • LAST MODIFIED: 27 June 2017
  • DOI: 10.1093/obo/9780195396577-0151


The language of thought hypothesis (LOTH) is a foundational and yet largely empirical thesis about how thoughts (as states) and thinking (as processes) are realized in creatures with sufficiently complex minds. It postulates a language-like system of mental representations as the vehicles of thought and thinking. These representations are presumed to be multiply realized in the brain (or the relevant hardware) of cognizers. This system is said to be a mental language (“Mentalese”) in virtue of satisfying the following two conditions: (i) its representations have a combinatorial (compositional) syntax and semantics, that is, complex representations of the system are systematically built out of the simple ones according to whatever grammar turns out to govern their constructions, and their semantics is a function of the semantics of their simple constituents together with their syntactic structure; and (ii) the operations defined over these representations are causally sensitive only to their syntax. In such a system, propositional attitudes such as beliefs and desires are identified with different computational relations to such mental representations. Condition (i) is a commitment to the representational theory of mind (RTM), whose history in one form or another goes back at least to the British empiricists with their postulation of simple and complex ideas. Condition (ii) is a newer development whose roots lie deeply in the development of modern symbolic logic and digital computers and is sometimes known as the computational theory of mind (CTR); this is the more controversial aspect of LOTH. Thus LOTH can be seen as the conjunction of RTM and CTM, sometimes abbreviated as CRTM.

General Overviews

Aydede 2010, Block 1995, and Rescorla 2015 are among the most comprehensive and historically sensitive article-length introductions to the language of thought hypothesis (LOTH), with slightly different emphases. The latter two focus more on the computational aspect of LOTH, whereas Aydede 2010 offers a more comprehensive and detailed presentation of the thesis. Maloney 1994 is a more concise introduction. Fodor 1985 presents a nice categorization of the positions in the approaches to mental representations, emphasizing various positions within the intentional realist camp, and offers the standard arguments for why LOTH is the best form of representational theory of mind (RTM). Pylyshyn 1990 is a longer but more in-depth and detailed overview.

  • Aydede, Murat. “The Language of Thought Hypothesis.” In The Stanford Encyclopedia of Philosophy. Edited by Edward N. Zalta, 2010.

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    This is the most up-to-date and comprehensive article-length introduction to LOTH, and like other Stanford Encyclopedia entries, it is updated regularly every four or five years. It also contains an overview of the debate between language of thought (LOT) theorists and connectionists.

  • Block, Ned Joel. “The Mind as the Software of the Brain.” In An Invitation to Cognitive Science. Edited by Daniel N. Osherson, Lila Gleitman, Stephen M. Kosslyn, S. Smith, and Saadya Sternberg, 377–425. Cambridge, MA: MIT, 1995.

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    This is a long article that officially gets to LOT only halfway through, but it lays out the theoretical and computational framework in a very intuitive and accessible (yet detailed) way. Contains very detailed but nontechnical discussion of the computer model of the mind, and distinguishes between intelligence and intentionality. Also discusses some criticisms of LOTH, such as John Searle’s Chinese room argument and Searle’s criticism that anything can be seen as a computer.

  • Fodor, Jerry A. “Fodor’s Guide to Mental Representation: The Intelligent Auntie’s Vade-Mecum.” Mind 94.373 (1985): 76–100.

    DOI: 10.1093/mind/XCIV.373.76Save Citation »Export Citation » Share Citation »

    Starts with the big divide between intentional realism (about propositional attitudes) and irrealism, then proceeds to describe the options for realists through a number of diagnostic questions, leading to the presentation of LOTH as the best account of attitudes. A very accessible and at times entertaining survey for a fairly general audience. Reprinted in Fodor, A Theory of Content and Other Essays (Cambridge, MA: MIT Press, 1994) as well as in Mental Representation: A Reader, edited by Stephen Stich, and T. Warfield (Oxford: Blackwell, 1994).

  • Maloney, J. Christopher. “Language of Thought (1).” In A Companion to the Philosophy of Mind. Edited by S. Guttenplan, 401–407. Oxford: Blackwell, 1994.

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    This is a shorter presentation. Clear and accurate.

  • Pylyshyn, Zenon W. “Computation and Cognition: Issues in the Foundations of Cognitive Science.” In Foundations of Cognitive Science: The Essential Readings. Edited by Jay L. Garfield, 18–74. New York: Paragon House, 1990.

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    Fairly detailed and comprehensive overview geared toward a more professional audience. Particular emphasis on the notion of cognitive architecture.

  • Rescorla, M. “The Computational Theory of Mind.” In The Stanford Encyclopedia of Philosophy. Edited by Edward N. Zalta. Stanford, CA: Stanford University, 2015.

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    Insightful, detailed, and historically sensitive discussion of computation and how it is relevant to the study of mind. Useful organization of the material. Clearly written.

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