ABSTRACT
The chapter proposes to ignore physiological findings about the development of the brain, even though these deal, of course, with necessary conditions for the development of rationality. The basic structure of author's account of the development of rationality will be provided by the work of Piaget. Rational behaviour and belief spring from the recognition, implicit or explicit, that certain general considerations are grounds for action or belief. The reference to the social aspect of 'reasonableness' introduces another cardinal feature of 'reason' which is its publicity. The first stage is what Piaget calls the intellectual revolution of the first two years. The child now apprehends the world as one in which enduring objects existing in time and space stand in causal relations, though causality is at first interpreted purely in terms of agency. The absence of any proper account of the development of sympathy is also a failure of Piaget's more specific work on moral development.
