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Newell and Simon

Original nameAllen Newell & Herbert A. Simon

American Computer Scientist Pair, Co-Inventors of the "Logic Theorist" Program

Those Who Conceived That "a Machine Could Think" · Pioneers

The Logic TheoristThe General Problem SolverThe Founding Theory of Symbolist AI

Who they are

Allen Newell (1927–1992) and Herbert Simon (1916–2001) were an American computer scientist pair who long worked together at Carnegie Mellon University, collaborating for nearly thirty years and acknowledged as among the most important founders of the symbolist school of AI. Their 1956 "Logic Theorist" program could automatically prove several theorems in Bertrand Russell and Alfred Whitehead’s classic Principia Mathematica (one proof even more concise than the original book’s), widely held to be the first true AI program in history. The two thereafter proposed the "physical symbol system hypothesis," holding that the essence of intelligent behavior is the manipulation and transformation of symbols, a hypothesis that thereafter became the core theoretical program of symbolist AI for decades, contending with the later-rising connectionist (neural network) path. Simon was also an economist, winning the 1978 Nobel Prize in Economics for his research on organizational decision behavior, and the two jointly won the Turing Award in 1975.

Primary sourcesNewell & Simon, Logic Theorist (1956)The 1978 Nobel Prize in Economics citation for Simon

Key stories

A Machine That Proved Mathematical Theorems, and Proved Them More Concisely Than a Human

The "Logic Theorist" program attempted to prove 52 theorems in Principia Mathematica, at last successfully proving 38, one of them even more concise and elegant than the proof in Russell and Whitehead’s original book. Newell and Simon enthusiastically sent this result to Russell himself, who replied that he was glad to see it, but wryly said that had he known earlier the effort spent on that proof could have been saved, he would have been happy — an anecdote thereafter often cited as the earliest amusing footnote to the research field of "machine-assisted proof" that flourished thereafter.

Relationships

Disciple

🕸️Judea Pearl　The causal-inference theory Pearl later proposed continued and challenged the symbolist, heuristic-search tradition Newell and Simon began

Ally

🏷️John McCarthy

Echoes today

Below are how modern works borrow or reinterpret this name or story — not the original material. The two differ, so keep them apart.

The lasting dispute of the "physical symbol system hypothesis"This hypothesis the two proposed thereafter long stood in opposition to the connectionist (neural-network) path, and this dispute over "whether symbolism or connectionism is the better" is in a sense not yet wholly settled to this day.

Appears in

"Can Machines Think?" — The Birth of AITuring’s Question and the Dartmouth Conference

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