Blockhead
Encyclopedia
Blockhead is the name of a theoretical computer
system invented as part of a thought experiment
by philosopher Ned Block, which appeared in a paper entitled Psychologism and Behaviourism. In this paper, Block argues that the internal mechanism of a system is important in determining whether that system is intelligent, and also claims to show that a non-intelligent system could pass the Turing Test
.
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
and grammatically
correct sentences that can be used to start a conversation. From this follows the point that there is a limit to how many correct responses can be made to this first sentence, and then again to the second sentence, and so on until the conversation ends.
Block then asks us to imagine a computer which had been programmed with all these sentences. Although the number of sentences required for a 30 minute
conversation is said to be greater than the number
of particles
in the universe
, it is clear that such a machine could at least logically exist (this makes for a purely theoretical argument which can't be applied in practice). From this, 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. On this basis, the computer would be able to pass the Turing test
despite the fact (according to Block) that 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
's Chinese Room
.
A recent objection to the Blockhead argument is Hanoch Ben-Yami (2005).
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
system invented as part of a thought experiment
Thought experiment
A thought experiment or Gedankenexperiment considers some hypothesis, theory, or principle for the purpose of thinking through its consequences...
by philosopher Ned Block, which appeared in a paper entitled Psychologism and Behaviourism. In this paper, Block argues that the internal mechanism of a system is important in determining whether that system is intelligent, and also claims to show that a non-intelligent system could pass the Turing Test
Turing test
The Turing test is a test of a machine's ability to exhibit intelligent behaviour. In Turing's original illustrative example, a human judge engages in a natural language conversation with a human and a machine designed to generate performance indistinguishable from that of a human being. All...
.
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
Syntax
In linguistics, syntax is the study of the principles and rules for constructing phrases and sentences in natural languages....
and grammatically
Grammar
In linguistics, grammar is the set of structural rules that govern the composition of clauses, phrases, and words in any given natural language. The term refers also to the study of such rules, and this field includes morphology, syntax, and phonology, often complemented by phonetics, semantics,...
correct sentences that can be used to start a conversation. From this follows the point that there is a limit to how many correct responses can be made to this first sentence, and then again to the second sentence, and so on until the conversation ends.
Block then asks us to imagine a computer which had been programmed with all these sentences. Although the number of sentences required for a 30 minute
Minute
A minute is a unit of measurement of time or of angle. The minute is a unit of time equal to 1/60th of an hour or 60 seconds. In the UTC time scale, a minute on rare occasions has 59 or 61 seconds; see leap second. The minute is not an SI unit; however, it is accepted for use with SI units...
conversation is said to be greater than the number
Number
A number is a mathematical object used to count and measure. In mathematics, the definition of number has been extended over the years to include such numbers as zero, negative numbers, rational numbers, irrational numbers, and complex numbers....
of particles
Elementary particle
In particle physics, an elementary particle or fundamental particle is a particle not known to have substructure; that is, it is not known to be made up of smaller particles. If an elementary particle truly has no substructure, then it is one of the basic building blocks of the universe from which...
in the universe
Universe
The Universe is commonly defined as the totality of everything that exists, including all matter and energy, the planets, stars, galaxies, and the contents of intergalactic space. Definitions and usage vary and similar terms include the cosmos, the world and nature...
, it is clear that such a machine could at least logically exist (this makes for a purely theoretical argument which can't be applied in practice). From this, 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. On this basis, the computer would be able to pass the Turing test
Turing test
The Turing test is a test of a machine's ability to exhibit intelligent behaviour. In Turing's original illustrative example, a human judge engages in a natural language conversation with a human and a machine designed to generate performance indistinguishable from that of a human being. All...
despite the fact (according to Block) that 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 Searle
John Rogers Searle is an American philosopher and currently the Slusser Professor of Philosophy at the University of California, Berkeley.-Biography:...
's Chinese Room
Chinese room
The Chinese room is a thought experiment by John Searle, which first appeared in his paper "Minds, Brains, and Programs", published in Behavioral and Brain Sciences in 1980...
.
A recent objection to the Blockhead argument is Hanoch Ben-Yami (2005).