[All] are taught some simple truths as children, only to discover as teenagers or young adults that those truths were far too simple and that they themselves were embarrassingly simple to have accepted them. They strike off on their own, leaving the comfortable mental world of their childhood to find a wider and stranger world of ideas. They may experience this world as disturbing or as liberating, but in any event it is more exciting. If they are fortunate, however, they may come to rediscover for themselves the truths they were taught as children. They may return home, as T.S. Eliot put it, and know it for the first time. If so, they may see that, although they first learned these truths as simple children, neither the truths themselves nor the people who taught them were quite as simple as they supposed.

This requires, however, the difficult feat of questioning twice in one’s life—of undergoing two revolutions in one’s thinking. It requires being critical even of the ideas that one encountered in the first flush of critical thinking in one’s youth.

--Stephen Barr, Modern Physics, Ancient Faith