This can be within the context of education as a societal institution or more broadly as the process of human existential growth, i.e. how it is that our understanding of the world is continually transformed via physical, emotional, cognitive and transcendental experiences.
Plato is the earliest important educational thinker. He saw education as the key to creating and sustaining his Republic. He advocated extreme methods: removing children from their mothers care and raising them as wards of the state, with great care being taken to differentiate children suitable to the various castes, the highest receiving the most education, so that they could act as guardians of the city and care for the less able. Education would be holistic, including facts, skills, physical discipline, and music and art, which he considered the highest form of endeavour. For Plato the individual was best served by being subordinated to a just society. Platos belief that talent was distributed non-genetically and thus must be found in children born to all classes moves us away from aristocracy, and Plato builds on this by insisting that those suitably gifted are to be trained by the state so that they may be qualified to assume the role of a ruling class. What this establishes is essentially a system of selective public education premised on the assumption that an educated minority of the population are, by virtue of their education (and inborn educability), sufficient for healthy governance.
Plato should be considered foundational for democratic philosophies of education both because later key thinkers treat him as such, and because, while Platos methods are autocratic and his motives meritocratic, he nonetheless prefigures much later democratic philosophy of education. This is different in degree rather than kind from most versions of, say, the American experiment with democratic education, which has usually assumed that only some students should be educated to the fullest, while