Yehoshua Bar-Hillel
Philosopher, Logician & Machine Translation Pioneer
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Yehoshua Bar-Hillel (1915–1975) was an Israeli philosopher and logician who worked at the intersection of language, information, and computation. With Rudolf Carnap he developed a theory of semantic information (1952–1953), an early attempt to put meaning back into Shannon's meaning-free measure of information. He was the first academic to work full-time on machine translation, at MIT, and organized the first conference on the subject in 1952 — then became its most influential skeptic, arguing that fully automatic high-quality translation is impossible without world knowledge (his example: only knowing the world tells you whether 'the box is in the pen' means a writing pen or a playpen). He spent his later career at the Hebrew University of Jerusalem.
Key Contributions
- Developed a theory of semantic information with Rudolf Carnap, addressing meaning that Shannon's theory set aside
- Became the first full-time academic researcher in machine translation and organized its first conference (1952)
- Argued that fully automatic high-quality translation requires world knowledge, a landmark critique of early AI optimism
- Contributed the Bar-Hillel (pumping) lemma for context-free languages in formal language theory
- Helped found computational linguistics at the Hebrew University of Jerusalem
Questions they sharpened View the streams
Papers & Publications
Connections
Rudolf Carnap
Influenced byPhilosopher & Logician
Bar-Hillel read Carnap's Logical Syntax of Language as a young man, corresponded with him through the 1940s, took a postdoctoral post under him in Chicago in 1950, and co-wrote the 1952 Outline of a Theory of Semantic Information, an attempt to give Shannon's meaning-free bits a measure of meaning. The disciple then carried Carnap's logic into machine translation and came back its sharpest skeptic. The line from one to the other runs from the hope that language can be fully formalized to the discovery of how much of it lives in knowledge of the world.
en.wikipedia.org · Carnap & Bar-Hillel, An Outline of a Theory of Semantic Information, MIT RLE Technical Report 247 (1952)
Hubert Dreyfus
InfluencedPhilosopher & AI Critic
What Computers Can't Do leans on Bar-Hillel at its key turns: his report on the state of machine translation, his 'fallacy of the successful first step', and his claim that because the facts we know are in a pregnant sense infinite, a translator stocked with an encyclopedia is 'utterly chimerical'. Dreyfus thought Bar-Hillel's pen-and-box example too physical and his infinity claim too strong, but he took over the core: understanding a sentence requires a world. He also quoted Bar-Hillel's doubt that machines that cannot learn 'in a sophisticated sense' would ever translate well, which turned out to be exactly where the field went.
Hubert L. Dreyfus, What Computers Still Can't Do (MIT Press, 1992), esp. pp. 215–216 and notes; full text: https://archive.org/details/what-computers-still-cant-do-a-critique-of-artificial-reason-hubert-l-dreyfus · Bar-Hillel, "The Present Status of Automatic Translation of Languages", Advances in Computers 1 (1960)
Claude Shannon
Influenced byMathematician & Father of Information Theory
Shannon's 1948 theory handed Bar-Hillel his problem. With Carnap he wrote An Outline of a Theory of Semantic Information (MIT, 1952), one of the first attempts to say that Shannon had measured signal transmission rather than information, and to supply what had been left out. Their measure keeps Shannon's logarithm but counts the possible worlds a sentence rules out, not the improbability of a signal. Bar-Hillel's debt was the debt of the dissenter who keeps the instrument and changes what it measures, and the gap between bits and meaning he pointed to is the one every argument about whether tokens carry meaning still crosses.
plato.stanford.edu · arxiv.org · dspace.mit.edu
