“When the rookery is pretty well filled, and the nest-building is in full swing, the birds have a busy and anxious time. To get enough of suitable small stones is a matter of difficulty, and may involve long journeys for each single stone. The temptation is too strong for some of them, and they become habitual thieves. The majority remain stupidly honest. Amusing complications result. The bearing of the thief clearly shows that he knows he is doing wrong. He has a conscience, at least a human conscience, i. e., the fear of being found out. Very different is the furtive look of the thief, long after he is out of danger of pursuit, from the expression of the honest penguin coming home with a hard-earned stone.

“An honest one was bringing stones from a long distance. Each stone was removed by a thief as soon as the owner’s back was turned. The honest one looked greatly troubled as he found that his heap didn’t grow, but he seemed incapable of suspecting the cause.

“A thief, sitting on his own nest, was stealing from an adjacent nest, whose honest owner was also at home, but looking unsuspectingly in another direction. Casually he turned his head and caught the thief in the act. The thief dropped the stone and pretended to be busy picking up an infinitesimal crumb from the neutral ground.”

“The Heart of the Antarctic,” Sir Ernest Shackleton, Vol. II, p. 253 (Section on the Adelie Penguin, by James Murray, Biologist of the Expedition).

The word “conscience” was perhaps originally synonymous with consciousness, but it gradually came to mean self-consciousness of a very special type, namely, the silent commendation or censure which a man may bestow upon his actions or his projects. This word “conscience” replaced the Middle English term inwit,—a term made famous in the title of a book (circa 1340) called the “Ayenbite of Inwit” (that is, the “Again-bite or Remorse of Conscience”). The concept of conscience has played an important part in modern ethical theory, and it is supposed by many persons to be the foundation of all morality. What place it deserves to hold in a constructive, mechanistic ethics can be determined, however, only by careful analysis. So many extravagant claims have been advanced in its behalf as to make one suspect that none of them are true. Things which people have “always heard lauded and never discussed” are only with difficulty saved from oblivion when intellectual revolutions have altered the emphasis which man puts on the values of life. It was thus with the word “soul,” and with the word “immortality,” and it is likely to be the same with the word “conscience.” At least it will be an advantage to look at the philosophical pedigree of this once mighty shibboleth.

It may be surprising to learn that as far as ethical theory is concerned, the doctrine of an infallible conscience is the product of no less recent a time than the XVIII century. The Conscience-theory is the philosophical property of such men as Butler, Clarke, Kant, Shaftesbury, and Reid, rather than of their predecessors. Thomas Hobbes (1588-1679), who founded critical English ethics, flatly refused to give to the then immature concept of conscience any recognition; indeed, he declared it to be nothing less than a “disease” of the state, and one “of those things that weaken or tend to the dissolution of a commonwealth.” In Chapter XXIX of the “Leviathan,” he states the current notions of conscience: (1) “That every private man is judge of good and evil actions,” and (2) “That whatsoever a man does against his conscience is sin.” Both of these notions Hobbes condemns. “For,” he observes with characteristic sagacity, “a man’s conscience and his judgment is the same thing, and as the judgment so also the conscience may be erroneous.”

This emphasis which Hobbes placed upon the untrustworthiness of private ethical judgments was fatal to his purpose. His successors began straightway to reanimate that which he had sought to bury once and for all, and, whether on account of their temperamental antipathy to the intellectualism of Hobbes, or because they were honestly seeking for some valid ethical principle, they asserted, first timidly, and later with a surprising boldness the very thing which Hobbes had sought especially to efface from the docket of ethical discussion.

We find this reaction beginning in Shaftesbury (1671-1713). Albeit this author gives a minor place in his ethical theory to the notion of a “moral sense,” or rational, reflex affection which approves only socially beneficial actions, yet the positive emphasis which he puts upon it is nevertheless significant. The affirmation proved to be contagious, for those who followed Shaftesbury immediately elevated conscience to a central position in their systems. We refer here to Butler, Clarke, Kant, and Reid, who are known as intuitionists.

According to Butler (1692-1752), conscience is a “principle of reflection” and not a mere feeling. And this principle of reflection is for him a natural or inherent property of man’s mind. It is the principle by which a man “approves or disapproves his heart, temper, and actions”; it is a faculty which “tends to restrain men from doing mischief to each other, and leads them to do good.” Be it noted here that Butler says nothing about the so-called infallibility of conscience, nor does he argue that it must be the same for all persons. Moreover, he gives a somewhat analytical definition of it, and is willing to grant that its function is utilitarian.

The old belief in the certainty of conscience now begins to reappear. It was Clarke (1675—1729) who attempted to defend it by the use of a mathematical analogy. We are all familiar with the axiom (or truism) that things which are equal to the same thing are equal to each other. If now we keep the general form, but alter the substance of this axiom, so that it reads: “Whatever I judge reasonable or unreasonable for another to do for me, that by the same judgment I declare reasonable or unreasonable that I in the like case should do for him,” we have Clarke’s Law of Equity. To an arm-chair philosopher such a statement sounds fairly cogent, but its empirical value is not thereby guaranteed. As every student of psychology knows, individual differences, individual preferences, and the capacity of individuals by this method of give-and-take are completely ignored in the formulation of this law. Besides, Clarke’s conception of conscience may be said to contain a hint of ethical solipsism, or the theory that oneself is the only accurate authority on social justice. We need not pause longer over the insuperable difficulties of such a point of view.