Intelligence is a multidimensional concept that is not amenable to any single definition or quantization. Take for instance the idea of “the size of a tree.” Size could mean height, drip radius, mass, volume of smallest convex polyhedron that contains the whole organism, volume of water displaced if the tree was immersed in a tank, trunk girth at 6 feet, etc. The tallest redwood is taller than the tallest sequoia, but isn’t the sequoia bigger? Why is it bigger? Because it has greater mass? But what of the biggest banyan? It has a greater mass than both the redwood and the sequoia.
The problem with intelligence is not that it’s not quantifiable, but that different researchers use different mapping functions all the while pretending they’re measuring the exact same thing, heaping up the confusion. If you pick one specific mental activity (arithmetic, visual memory, music-compositional ability, language processing), it is rarely very difficult to measure and rank people by their adeptness. If, on the other hand, you try to come up with a “good” way to map many different intelligences together onto some scale, you’re going to be terrible at using this scale to predict individual performance at specific tasks. Further, individuals with low IQ (or other attempted measure at general intelligence) may be brilliant at specific tasks because of their low IQ in that because much of their brain is dedicated to that task, they have little left over for anything else. This is especially true of many autistic individuals.
In the end, intelligence is rather easy to define if you recognize it as the multifaceted phenomena that it is.
Intelligence is a multidimensional concept that is not amenable to any single definition or quantization. Take for instance the idea of “the size of a tree.” Size could mean height, drip radius, mass, volume of smallest convex polyhedron that contains the whole organism, volume of water displaced if the tree was immersed in a tank, trunk girth at 6 feet, etc. The tallest redwood is taller than the tallest sequoia, but isn’t the sequoia bigger? Why is it bigger? Because it has greater mass? But what of the biggest banyan? It has a greater mass than both the redwood and the sequoia.
The problem with intelligence is not that it’s not quantifiable, but that different researchers use different mapping functions all the while pretending they’re measuring the exact same thing, heaping up the confusion. If you pick one specific mental activity (arithmetic, visual memory, music-compositional ability, language processing), it is rarely very difficult to measure and rank people by their adeptness. If, on the other hand, you try to come up with a “good” way to map many different intelligences together onto some scale, you’re going to be terrible at using this scale to predict individual performance at specific tasks. Further, individuals with low IQ (or other attempted measure at general intelligence) may be brilliant at specific tasks because of their low IQ in that because much of their brain is dedicated to that task, they have little left over for anything else. This is especially true of many autistic individuals.
In the end, intelligence is rather easy to define if you recognize it as the multifaceted phenomena that it is.