In this thesis, it is argued that the fundamental goal of education is one of equipping individuals to partake of the good life as members of a just democratic society. It is argued further that a necessary condition for the realisation of this goal is that individuals are equipped to think well; more precisely, to make decisions on the basis of arguments that are both logically cogent (that is, which have true premises and which are either inductively strong or deductively valid) and ethically grounded (that is, with premises which express appropriate regard for the welfare of others). The concern of the thesis is the role education might play in fostering both the capability and the readiness to engage widely in such thinking. Although this concern has a long and complex history within the Western tradition, insufficient educational progress has been made. It is suggested that progress has been hampered on the one hand by the stark disciplinary divide between the descriptive approach of psychology and the normative stance of philosophy; and on the other, by a failure on the part of educational programme developers to take into account the constraints of prevailing educational structures. It is argued that what is needed is a new model of interdisciplinary research.