"Conscience, indeed, is a frightful Apparition itself, and I make no Question but it oftentimes haunts an oppressing Criminal into Restitution, and is a Ghost to him sleeping or waking: nor is it the least Testimony of an invisible World that there is such a Drummer as that in the Soul, that can beat an allarm when he pleases, and so loud, as no other Noise can drown it, no Musick quiet it or make it hush, no Power silence it, no Mirth allay it, no Bribe corrupt it."
— Defoe, Daniel (1660?-1731)
Conscience raises many a Devil, that all the Magick in the World can't lay; it shows us many an Apparition that no other Eyes can see, and sets Spectres before us with which the Devil has no Acquaintance; Conscience makes Ghosts walk, and departed Souls appear, when the Souls themselves know nothing of it.
This thing called Conscience is a strange bold Disturber, it works upon the Imagination with an invincible Force; like Faith, it makes a Man view things that are not, as if they were; feel things that are not to be felt, see things that are not to be seen, and hear things that are not to be heard; it commands the Senses, nay even the Tongue it self, which is so little under Command, submits to this sovereign Mandate; and tho' I do not see that Conscience always over-rules it to Silence, yet it often makes it speak, even whether it would or no, and that to its own Ruin and Destruction; making the guilty Man accuse himself, and confess what his Policy had before so effectually conceal'd, that no Eye had seen it, no Evidence could prove it.
Text from An Essay on the History and Reality of Apparitions: Being an Account of What They are, and What They are Not; Whence They Come, and Whence They Come Not. (London: Printed: and sold by J. Roberts, 1727). <Link to ECCO-TCP>