Blockhead is the name of a theoretical computer system invented as part of a

thought experiment A thought experiment is a hypothetical situation in which a hypothesis, theory, or principle is laid out for the purpose of thinking through its consequences. History The ancient Greek ''deiknymi'' (), or thought experiment, "was the most anci ...

by philosopher

Ned Block Ned Joel Block (born 1942) is an American philosopher working in philosophy of mind who has made important contributions to the understanding of consciousness and the philosophy of cognitive science. He has been professor of philosophy and psych ...

, which appeared in a paper titled "

Psychologism Psychologism is a family of philosophical positions, according to which certain psychological facts, laws, or entities play a central role in grounding or explaining certain non-psychological facts, laws, or entities. The word was coined by Johann ...

and Behaviorism". Block did not name the computer in the paper.

Overview

In "Psychologism and Behaviorism," Block argues that the internal mechanism of a system is important in determining whether that system is intelligent and claims to show that a non-intelligent system could pass the

Turing test The Turing test, originally called the imitation game by Alan Turing in 1950, is a test of a machine's ability to exhibit intelligent behaviour equivalent to, or indistinguishable from, that of a human. Turing proposed that a human evaluato ...

. Block asks us to imagine a conversation lasting any given amount of time. He states that given the nature of language, there are a finite number of

syntactically In linguistics, syntax () is the study of how words and morphemes combine to form larger units such as phrases and sentences. Central concerns of syntax include word order, grammatical relations, hierarchical sentence structure ( constituency) ...

- and grammatically-correct sentences that can be used to start a conversation. Consequently, there is a limit to how many "sensible" responses can be made to the first sentence, then to the second sentence, and so on until the conversation ends. Block then asks the reader to imagine a computer which had been programmed with all the sentences in theory, if not in practice. Block argues that such a machine could continue a conversation with a person on any topic because the computer would be programmed with every sentence that it was possible to use so the computer would be able to pass the Turing test despite the fact that — according to Block — it was not intelligent. Block says that this does not show that there is only one correct internal structure for generating intelligence but simply that some internal structures do not generate intelligence. The argument is related to

John Searle John Rogers Searle (; born July 31, 1932) is an American philosopher widely noted for contributions to the philosophy of language, philosophy of mind, and social philosophy. He began teaching at UC Berkeley in 1959, and was Willis S. and Mari ...

Chinese room The Chinese room argument holds that a digital computer executing a program cannot have a " mind," "understanding" or "consciousness," regardless of how intelligently or human-like the program may make the computer behave. The argument was pre ...

. A recent objection to the Blockhead argument is Hanoch Ben-Yami (2005), who agrees that Block's machine lacks intelligence but compares its answers to a poetic dialogue in which one man is whispered romantic poetry to recite to his would-be lover as it answers only what it has been told to answer in advance by its programmers.

Sources

* . * . * Theory of computation Philosophy of artificial intelligence Thought experiments in philosophy of mind {{philosophy-stub

Overview

Sources

See also