G.K. Chesterton on the denial of original sin, from his book Orthodoxy:
The strongest saints and the strongest skeptics alike took positive evil as the starting point of their argument. If it be true (as it certainly is) that a man can feel exquisite happiness in skinning a cat, then the religious philosopher can only draw one of two deductions. He must either deny the existence of God, as all atheists do; or he must deny the present union between God and man, as Christians do. The new theologians seem to think it a highly rationalistic solution to deny the cat.