Professor John McCarthy
Father of AI


Ascribing Mental Qualities to Machines

This paper concerns what it means for a machine to have beliefs. This started the dispute about whether thermostats could be considered to have beliefs. It was published in 1979 in an obscure collection and reprinted in my 1990 book 'Formalizing Common Sense'.

Ascribing mental qualities like beliefs, intentions and wants to a machine is sometimes correct if done conservatively and is sometimes necessary to express what is known about its state. We propose some new definitional tools for this: definitions relative to an approximate theory and second order structural definitions.

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