For the assessment of intelligence Alan Turing has devised a formal test which is now widely known as the Turing Test (for a short explanation see Appendix A). In short: ``It is proposed that a machine may be deemed intelligent, if it can act in such a manner that a human cannot distinguish the machine from another human merely by asking questions via a mechanical link.'' [Abe98] This hypothesis first gained momentum by the increase of knowledge on the biological brain. The neurobiological processes were first thought to be similar to or identical to the information processes of a computer.

John Searle disputed the notion that the brain is a computer at the fundamental level. He proposed the Chinese Room thought experiment. In short, it is a closed room with a person in it that knows no Chinese. He receives a message which he considers non-informational `data', but he applies instructions that are provided on cards in the room. The instructions allow him to generate an answer that appears to come from someone that understands Chinese. Still, the man is not consciously aware of what is being discussed. While the man, the room nor the cards can be said to be `aware' of it, there is no awareness in play. Similarly, an algorithmic machine would never be aware, or `understand' what it processes. [Sea80]

The neurobiological view was supported by the notion that once we have sufficient understanding of the laws of physics and the structure of the brain, we would be able to precisely simulate the operation of a brain. Hence, the operation of the brain would be computable.

Erik de Bruijn 2007-10-19