A guilty conscience needs no accuser Cf. Disticha Catonis i. xvii. conscius ipse sibi de se putat omnia dici, the man with something on his conscience thinks he is always the subject of talk. For Catoun [Dionysius Cato] seith that he that gilty is Demeth alle thyng be spoke of him. [c 1390 Chaucer Canon's Yeoman's Prologue l. 688] A Guilty conscience is a worme that bites and neuer ceaseth. ‥A guiltie conscience is neuer without feare. [1597 Politeuphuia 10V] A guilty Conscience self accuses. A Man that has done ill‥shews his Guilt. [1721 J. Kelly Scottish Proverbs 9] It is an old saying, a guilty conscience needs no accuser. [1744 Life & Adventures Matthew Bishop viii.] ‘Where are you off to?’ asked George with a great effort. ‥A guilty conscience needs no accuser. [1881 D. C. Murray Joseph's Coat I. viii.] ‘Why should I think that?’ I said, groping for his identity. ‘Because you were thinking about me.’ Then I knew he was speaking of Hinckman's murder and must be the murderer—‘a guilty conscience needs no accuser.’ [1952 Ellery Queen's Mystery Mag. Apr. 25] http://www.answers.com/topic/a-guilty-conscience-needs-no-accuser Of anthropologists some do and some do not accept the Biblical account of man's origin; and the former class, admitting that Adam's descendants might soon have lost the traces of their higher descent, are willing to hear, with no pledge of endorsing, what the latter class have to say on the assumption of the human development even from an animal ancestry, and on the further assumption that in the use of evidences they may neglect sequence of time and place. It is not maintained by any serious student that the Darwinian pedigree is certainly accurate: it has the value of a diagram giving some notion of the lines along which forces are supposed to have acted. Not, then, as accepting for fact, but as using it for a very limited purpose, we may give a characteristic sketch of ethical development as suggested in the last chapter of Dr. L. T. Hobhouse's "Morals in Evolution". It is a conjectural story, very like what other anthropologists offer for what it is worth and not for fully certified science. http://www.newadvent.org/cathen/04268a.htm Through conscience and its related notion, synderesis, human beings discern what is right and wrong. While there are many medieval views about the nature of conscience, most views regard human beings as capable of knowing in general what ought to be done and applying this knowledge through conscience to particular decisions about action. The ability to act on the determinations of conscience is, moreover, tied to the development of the moral virtues, which in turn refines the functions of conscience. Secular views of conscience Modern day scientists in the fields of Ethology, Neuroscience and Evolutionary psychology seek to explain conscience as a function of the human brain that evolved to facilitate reciprocal altruism within societies. As such it could be instinctive (genetically determined) or learnt. Psycho-Analytical views The psychologist Sigmund Freud regarded conscience as originating in the superego, which takes its cue from our parents during childhood. According to Freud, the consequence of not obeying our conscience is "guilt," which can be a factor in the development of neurosis. Your conscience is the measure of the honesty of your selfishness. Bio-Psychological views Conscience can prompt different people in quite different directions, depending on their beliefs, suggesting that while the capacity for conscience is probably genetically determined, its subject matter is probably learnt, or imprinted, like language, as part of a culture. For instance, one person may feel a moral duty to go to war, another feels a moral duty to avoid war under any circumstances. Numerous case studies of brain damage have shown that damage to specific areas of the brain (e.g. the anterior prefrontal cortex) results in the reduction or elimination of inhibitions, with a corresponding radical change in behaviour patterns. When the damage occurs to adults, they may still be able to perform moral reasoning; but when it occurs to children, they may never develop that ability. Conscience as society-forming instincts The human animal has a set of instincts and drives which enable us to form societies: groups of humans without these drives, or in whom they are insufficiently strong, cannot form cohesive societies and do not reproduce their kind as successfully as those that do. They either cannot survive in nature, or are defeated in conflict with other, more cohesive groups. http://en.wikipedia.org/wiki/Conscience

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for the criminal there is the law man, your path is what you are, and there is an antithesis to everything and everyone. for instance when the people of a nation are dominantly "good" the ruler must be "evil" visa vi. good question though.