Truth is within ourselves; it takes no rise From outward things, what'ere you may believe. There is an inmost centre in us all, Where truth abides in fulness; and around, Wall upon wall, the gross flesh hems it in, This perfect, clear perception -- which is truth ... and to KNOW, Rather consists in opening out a way Whence the imprisoned splendor may escape, Than in effecting entry for a light Supposed to be without.
~ from "Paracelsus" by Robert Browning with thanks to John Bryan