Education is dangerous. Authoritarian governments and religions have persistently tried to control the content of education and ration its distribution. In the colonial world, education was always a site of struggle as the colonizing powers sought control and modernization, and the colonized sought some balance between protecting local cultures and winning new knowledge and resources. Currently, a major shift is happening between old forms of inequality based on institutional segregation and new forms of inequality based on market mechanisms. Individuals cannot sensibly define a socially just education system by removing ourselves from this scene, as if justice could only be realized on another planet. They need to think principles through in relation to the real problems of contemporary education. In modern education systems, educators' mutual responsibility for children (and for adult learners) is mediated through a school system. Just education can be regarded as a system designed to make this responsibility effective. A just education system can allow itself to trust: to trust learners, without the whip of examination, and to trust teachers, without the club of auditing. It seeks security rather than insecurity, knowing that a basic security allows both deep learning and intellectual and cultural adventuring.