The perception of truth depends as much on the state of him that desires to perceive as on the objects that are presented to his view. No slight or swift or uniform process will enable any one to master the mere art of discerning truth from false appearance. But, not to speak of this most needful and most various mental preparation, there is another condition which is never forgotten with impunity. The more we know of truth, the more we come to see how manifold is the operation by which we take hold of it. It is not reached by one organ but through many. No single faculty, if indeed there be any single faculties, can arrogate a right to exclude from the domain of truth what cannot be readily subjected to its own special action. It may be that no element of our compound nature is entirely shut out from taking part in knowledge. It is at all events certain that the specially mental powers will never be able to judge together in rightful relation when the nature as a whole is disordered by moral corruption. There is no evil passion cherished, no evil practice followed, which does not cloud or distort our vision whenever we look beyond the merest abstract form of things. There is a truth within us, to use the language of Scripture, a perfect inward ordering as of a transparent crystal, by which alone the faithful image of truth without us is brought within our ken. Not in vain said the Lord that it is the pure in heart, they whose nature has been subdued from distraction into singleness, who shall see God; or, we may add, who shall see the steps of the ladder by which we may mount to God.
The stedfast and prescient pursuit of truth is therefore itself a moral and spiritual discipline.
F.J.A. Hort, The Way, The Truth, The Life (London, 2nd edn. reprinted 1897) 92-3, quoted in Andrew Louth, Discerning the Mystery. An Essay on the Nature of Theology, (Oxford: Clarendon, 1983) 57.