There exists no single, clear and concise definition of intelligence, however many have been suggested (see above and [LH06] for 70 more). The fact that the definition of intelligence has received such devoted attention and still resists clarification so thoroughly, is alarming [Reb95,Jen99, part III, §11]. Because the first definitions given were rooted in psychology, specifically psychometrics (dealing mostly with measuring the human IQ), it inherited a cultural subjectivity of what is to be dubbed intelligent. Consequently, measuring how intelligent something is may be debated endlessly. Since the purpose of concise definitions is to prevent ambiguities and the resulting endless discussions (see your dictionary for a definition of the word 'definition'), we may want to lessen the definitional burden. What intelligence involves is quite simple to identify: abstraction, learning and dealing with novelty. Whether it is exactly this set of abilities that is fundamental, or another is hard to determine. Certainly, there is some consensus around the data on intelligence. It shows that most suggested abilities are significantly correlated, leading to the discovery of the g factor1.7. If it is ever pin-pointed what intelligence precisely is, or when scientists finally concur, most theories that have strong support will all be very close because of this strong correlation and overlap of these notions. It is exactly the correlation that reveals that a general principle is responsible for emergence of these abilities. Moreover, Jensen emphasizes that ``[i]t is not essentially a psychological or behavioral variable, but a biological one, a property of the brain.'' [Jen99, p. 1] In this research, intelligence is approached from an evolutionary and biologically inspired perspective.
There is some general agreement that evolution is an important driving force of intelligence. In animals (specifically chordates), neural networks have served as the substrate for evolution of higher behavior.
Erik de Bruijn 2007-10-19