ABSTRACT
This discussion began originally, in Chapter 1, with the puzzle of the high intelligence-test scores that are sometimes found after a surgeon has destroyed a large part of the human brain. A tentative explanation was suggested, that these scores are due to a conceptual development which brain damage does not easily reverse. The chapters that followed have tried to make this intelligible physiologically (besides showing what the implications are for other problems). “Conceptual development,” “insight,” “thought,” and so on, have been given a physiological meaning, and a possible basis has been provided for seeing how capacities could be retained, once developed, despite brain injury which if it had occurred in infancy would have prevented the development. This chapter returns to the original problem of the effects of brain operations on intelligence. It presents an interpretation which fundamentally concerns the nature of intelligence, its normal development, and its later decline with old age.
