Descartes does not reject his early education because it was poorly taught or because he was a poor student. He rejects it because he came to see that it had produced in him a mixture of genuine knowledge and confident error with no reliable way to distinguish between them. He had been given tools for disputation — not tools for discovery. The accumulation of received opinions, each adding another layer, had built a structure with no secure foundation. The only remedy was to start again.
He is careful, however, to say that he would never recommend this course to everyone. A person who tears down an established building to rebuild it had better know what they are doing. The same is true of the mind: only someone who has the ability to guide themselves safely through radical doubt should attempt it. For everyone else, the risks of collapsing into scepticism without finding firm ground on the other side are too great.
The image of the lone walker in darkness captures the existential dimension of Descartes' project. He is not a revolutionary destroying tradition for sport but a careful explorer moving through unfamiliar territory, testing each step before committing weight to it. The slowness is not timidity; it is the appropriate response to the difficulty of the ground. In philosophy, more than anywhere else, haste produces disaster.
Descartes draws an analogy with architecture and city planning: a city built by a single architect according to a rational plan is more beautiful and coherent than one that has grown by accretion over centuries. The same is true of knowledge: a system built on a single set of principles, derived step by step from firm starting points, is more reliable than one assembled from the contributions of many centuries and many thinkers with conflicting assumptions. This is a defence not of arrogance but of coherence — the kind of unified rational structure that the Meditations attempts to construct.
The metaphors of building and rebuilding run through Part II of the Discourse. Descartes' analogy between knowledge and architecture or city-planning became influential in Enlightenment thinking about rational reconstruction. The same theme appears in the opening of the Meditations on First Philosophy.