'...doubts enter into the mind almost imperceptibly: they exist only as vague indistinct surmises, and by no means take the precise shape or substance of a formed opinion. At first, probably, they even offend and startle by the intrusion; but by degrees the unpleasant sensations they once excited wear off: the mind grows more familiar with them. A confused sense (for such it is, rather than a formed idea) of its being desirable that their doubts should prove well founded, and of the comfort and enlargement which would be afforded by that proof, lends them much secret aid. The impression becomes deeper, not in consequence of being reinforced by fresh arguments, but merely by dint of having long rested in the mind; and as they diffuse themselves over the whole of religion, and possess the mind in undisturbed occupancy.'
William Wilberforce, A Practical View of Christianity, p.265.