18. Since evil and falsity are opposite to good and truth, it is plain that truth cannot be conjoined to evil, nor good to the falsity of evil; if truth be adjoined to evil, it is truth no longer, but falsity, because it is falsified; and if good be adjoined to the falsity of evil, it is good no longer, but evil, because it is adulterated. But falsity which is not of evil may be conjoined to good.
