There are numerous urges rooted in man's nature each of which plays an important role in his welfare and development. The greatest power that moves the wheels of life and motivates individuals comes from the urges whose source lies within their being.
As long as the bonds that relate a person to life are there, he does not cease to crave and the flames of desire keep burning in his heart. All the continuous hardships and pains that he bears and undertakes are for the sake of satisfying his inner desires. As i soon as one of his desires is fulfilled, another sprouts in his heart, I impelling his body to action and effort and compelling him to begin a new activity and endeavour.
Man cannot find the path of happiness solely through the guidance of nature. The animals, on the other hand, traverse the course of their development through innate guidance by relying upon their instincts, by the help of which they regulate and discipline their lives. It is instinct that determines the functions of every animal species in accordance with its laws and they do not stand in need of education and training for knowing how to regulate their lives. However, in the case of the human being instinct is not capable of assuming this regulating role as in the case of animals and protecting him from deviation and destruction. It is reason and intellect, man's primary guide, that distinguishes him from other animals in showing him the path of life. It is through intellect and thought that man can recognise the path of his felicity and direct his efforts towards this end, until he attains to the highest goal that is worthy of him.
The caravan of humanity makes its onward journey with the guidance of intellect and thought, and it is with the assistance of reason that humanity solves its vital problems, conquering a new front every day in its struggle the problems posed by nature. In the great battlefield within the human spirit there is always a tough battle going on between reason and instinct. These two powers are pitched in a relentless battle in which each of them seeks to overpower the other. In order that we may benefit from our inner powers and remain secure from their harm, we must bring instincts under the domination of reason, to which all other urges, impulses and motives of ours must submit in complete obedience. It is reason which is our most invaluable asset that reveals to us the real dangers that we face and gives an order and discipline to life by teaching us the right way of employing our inner powers.
Of course, the intensity of desires is not the same at different stages of life and the character and configuration of the urges and motives changes according to age, conditions and circumstances.
In the same way as it possible for man to lay the foundations of his welfare on the basis of reason and will power without allowing the dangerous internal enemy to dominate his soul, it is also possible that he may be overcome by rebellious urges and be ultimately drowned in the dark and terrible vortex of corruption and decadence. Hence if he is interested in his own welfare he must build a firm shield to protect his soul from the harm of delusive urges and plan his course from the very beginning. He should know where the blind alley of desires would ultimately land him so that by the means of giving a system to his thoughts he may spend the springtime of life in the shadow of virtue and piety; for without sacrifice and forbearance, which are essential to life, it is not possible to spend a 1ifetime with purity and dignity.
Someone who gives special care to the principles of human virtue from the beginning of his rational existence, getting used to avoiding vices, develops his spiritual capacities in the best possible manner. For him the continuation of this policy will be easier at the more mature stages of life. After passing safely out of the critical frontiers of youth, the dangers of deviation will be reduced and the person will become somewhat immune against corruptive influences.
An absolute freedom in regard to satisfaction of inner desires, in addition to leaving evil and undesirable effects on the individual's soul and personality, also weaken the very foundations of social security. Hence, in order to attain personal welfare and happiness, as well as to protect the order of society, it is necessary to overlook a part of one's desires.
Professor Alexis Carrel says:
We have not yet learnt to submit to the laws of life in the same way as we submit to the laws of physics and gravity. There is a tragic conflict between human freedom and the laws of nature, a conflict to which modern man is prey, for man wants absolute autonomy. Nevertheless, he cannot without peril make use of his freedom beyond its permissible limits.
Freedom, like dynamite, as an effective but dangerous means whose way of utilization has to be learnt. Fortunately, the one who can make use of it is someone who possesses reason and will. Accordingly, this submission to the natural laws involves the limitation of the freedom of will. Life is not possible without an internal order.
The conflict between human freedom and the consequents of natural laws necessitates an exercise in self-discipline. In order that we may deliver ourselves and our descendants from the danger of catastrophes, we must resist most of our wishes, expectations and desires. A harmony with the order of the universe is not possible without sacrifice, and sacrifice is a law of life. It is by refraining from satisfying some desires that health and power can be secured. Greatness, beauty, and holiness cannot exist without sacrifice.
Every one must sacrifice because sacrifice is one of the necessities of human life. This necessity has emerged from the time when instinct gave way to free intellect in our ancestors Every time that man has made total use of his freedom, he has violated the natural laws and faced severe punishment. 
The Capacities of the Intellect
The intellect is one of the greatest gifts of God to man and with which man has been blessed. God says in the Holy Qur'an:
(It means:) O Prophet, declare that it is God Who has brought you out of non-being and given you existence and bestowed upon you hearing, vision and an aware heart (so that you should thank Him for His bounties), though there are few persons who are grateful to their Lord for His gifts. (67:23)
The Master of the Faithful, may peace be upon him, says:
The intellect is man's most precious asset, for it restores his dignity after his humiliation, uplifts him if he falls, guides him if he is lost and gives firmness and rectitude to his speech when he speaks. 
In Islamic teachings the intellect has been considered as man's 'inner' prophet and guide and as God's 'proof'. Imam al-Kazim, may peace be upon him, said:
God has appointed two kinds of guides for mankind. One is outward and manifest and the other is inward and hidden. The manifest proof are the prophets, messengers and the holy leaders of the faith. The hidden proof is the intellect. 
Since the intellectual capacities of people are not of the same level and are different in degrees, every man on the Day of Judgement will be held responsible in proportion to his intellectual ability. The Fifth Imam said:
On the Day of Judgement God shall scrutinise the record of His creatures', conduct (with a severity) in proportion to their intellectual capacities in the world. 
In the present era man has been greatly fascinated by the wonderful accomplishments of reason in the form of scientific discoveries, considering them the ultimate purpose and end of life. This enchantment has dealt an irremediable blow to the role of the intellect and its place in human life. It has caused him to ignore and neglect the power and faculty which has a direct connection with the suprasensible and the Source of being. Had the enchanted man seen the distant and wider horizon and ventured into the vast panorama of the suprasensible, he would not have stopped at the fascinating manifestations of reason. Islam is fully cognisant of the real worth and capacity of the intellect and the scope of its activity. It is on the basis of this knowledge that it has given so much care to the training and growth of the intellect so that it may view the realities of existence with thoughtful care. The Qur'an asks the intellect not to hold on to anything which has not been proved with certainty and beyond doubt. It requires the intellect not to accept anything until there is a clear and decisive proof to justify such acceptance.
And follow not that which thou hast no knowledge of; the hearing, the sight, the heart-all of those shall be questioned of. (17:36)
This express warning clearly underlines the necessity of making sufficient investigation before accepting anything as true. Similarly, the Qur'an points out the deviant character of those who do not base their beliefs on certainty and merely follow their conjectures and presumptions. It says about them:
They follow only surmise, and surmise avails naught against truth. (53:28)
Thereupon by adopting a firm approach based on an unshakeable reasoning it demolishes the intellectual foundations of blind imitation and surmise. It warns the blind and unquestioning followers who blindly imitate the creed and beliefs of their ancestors that their approach is sheer folly.
They say, 'No; but we will follow such things as we found our fathers doing.' What? And if their fathers had no understanding of anything, if they were not guided ? (2:170)
These exhortations are aimed to develop a critical mind and to put the intellect back in its true role by rejecting reliance on surmise and conjecture. By this means it seeks to habituate the intellect to discipline and critical scrutiny in its field of action, so that thereby it may regulate the various faculties and set in order the ideas and conceptions under its dominion. The kind of thinking that Islam requires is not one of an abstract kind removed from concrete realities that takes the form of philosophical speculation. By calling attention to the signs (ayat) of creation it seeks to awaken the intellect so that man may employ his conscious faculties to contemplate profoundly regarding the signs of Divine Majesty and Wisdom manifested in the system of creation. It is a thinking that is free from fantasy, free and perceptive of realities, not one which is lost in the dark wilderness of fancies. It is thinking that links man, with his perception and senses, to the Divine Spirit that circulates through the entire world of being, and this is the highest merit of the intellect.
Spinoza, the European philosopher, writes:
The highest thing which the mind can understand is God, that is to say, Being absolutely infinite, and without whom nothing can be nor can be conceived, and therefore that which is chiefly profitable to the mind, or which is the highest good of the mind, is the knowledge of God. Again, the mind acts only in so far as it understands and only in so far can it be absolutely said to act in conformity with virtue. To understand, therefore, is the absolute virtue of the mind. But the highest thing which the mind can understand is God (as we have already demonstrated), and therefore the highest virtue of the mind is to understand or know God. 
The ultimate purpose of thought and inquiry in Islam is to cure the human heart and to lay the foundation of life on truth and justice. When a person arrives at a certain conclusion through thinking and is made profoundly conscious of its implications, he puts it into action and implements it in his practical life. Once that dynamic conviction informs his thought, behaviour and faculties of perception, he is prepared for a serious struggle against every indignity that compromises the real worth of the human being. Although the intellect is the best guide and the biggest source of discernment, it loses its brilliance as a result of the curtain that obfuscating desires and lusts draw over the intellect and obstruct its light. Then the intellect practically loses its capacity of guidance. The Qur'an refers to the misguiding role of desires and lusts in these words:
Then (O Prophet) if they do not respond to thee, know that they are only following their desires: and who is further astray than he who follows his desire without guidance from God? Surely God guides not the evildoers. (28:50)
Nay, but the evildoers follow their own desires, without knowledge.... (30:29)
Had the Truth followed their desires, the heavens and the earth and whosoever is in them had surely corrupted. (23:71)
Hast thou seen him who has taken his desire to be his god, and God has led him astray out of a knowledge. (45:23)
Without doubt, to overcome and control one's desires and negative urges is a very difficult task. Only with persisting efforts and exercises can one keep the rebellious passions in check and make them tractable and subject to reason. This is the way to overcome the tyranny of desires and to benefit from them in a right and worthy manner. The Noble Prophet, may God bless him and his Household, once addressing a group of warriors returning from the battlefield said to them:
'Bravo to those who have accomplished the minor jihad and who yet remain to wage the major jihad!' He was asked, 'O Messenger of Allah, what is that major jihad?' He replied, 'That is the jihad against the self.
He who attains bliss and nearness to God is one who is vigilant over his violent and dangerous urges and one who does not allow his carnal motives to dominate his intellect and turn him to impiety and aberration.
But as for him who fears the station of his Lord and forbids the soul its desire, surely Paradise shall be the refuge. (79:40-41)
Is Conscience a Product of Internalised Prohibition?
Another major moderating agent of the instincts and impulses of the human psyche is moral conscience. Since the beginning of man's appearance on the earth until today long ages have passed and man has throughout been inclined towards goodness and abhorred vice. He has always heard an inner moral voice calling from within called 'conscience'. His rational life throughout the ages has existed by the side of the life of conscience.
When man can distinguish between thorns and flowers, avoiding the former and relishing the latter, when he can distinguish between filth and cleanliness, certainly he does not confuse between virtue and vice. The fundamental nature of the conscience is one of the most attractive phenomena of creation.
Man in a state of spiritual equilibrium is attracted to honesty and justice and is repelled by dishonesty and injustice. In fact moral conviction is more pronounced than rational conviction, which has a definite value for ascertaining facts. That is because the mind is well aware that the knowledge of external objects perceived by it, which carries the stamp of conviction put on it by the intellect, pertains to a reality separate from and external to the mind, where as the certainty created by the conscience stands above the kind of certainty that goes with perception and observation. In the case of moral conviction, the object is felt as a part of the subject.
Some psychoanalysts, like Freud and his followers, deny that moral conscience is inherent in man. They believe that repressed wishes and social inhibitions that become deposited in the unconscious mind make up what is called 'conscience'. In other words, conscience is a product of civilisation and has no essential roots in the human psyche.
Freud in his psychological investigations and analysis of various phenomena looks for sexual roots and pays no attention to other inner factors that form the source of good and bad actions.
There has been no society in the world that may consider dishonesty, injustice and breach of trust as something good and honourable, or honesty, justice and loyalty as bad and improper, or one which should consider its welfare and felicity to lie in vices and moral evils.
Freud's theory would be applicable if man had learnt to distinguish between good and evil through experience. But those virtues and vices which have been recognised by all men on the surface of the earth, civilised and savage, and even by peoples ignorant of the teachings of prophets and reformers, can never be said to be products of social prohibitions and repressed impulses.
Freud's denial of the innate nature of conscience-in the sense understood by ethics-and his degradation of the human being to an assembly of purely physical impulses and instincts, leads him inevitably to a total negation of all moral values and spirituality as well as the worth and sublimity of man's sacred urges so active in the depths of his psyche. This denial makes all its manifestations, such as compassion, justice, goodness, and helpfulness for the weak and the helpless, meaningless and absurd.
On the basis of such a doctrine, no one can take a step towards the world of spiritual and moral values without repressing his natural urges and instincts and forego pleasures by relying on his will power. Rather, according to it, all inner restraints are totally a product of external forces of social compulsion.
Should the conscience be considered a product of the forces of external environment, the actions of those who without any selfish benefit in view voluntarily deny themselves many pleasures for the sake of attaining to higher ideals and goals, and put up with pains and sufferings in the way of higher interests, remain unexplained by Freud's inadequate ideas, which view them as a subterfuge of the unconscious as a compensation for repressed wishes. The majesty of surrender to the guidance of the conscience will always remain a difficult and insoluble enigma for such theories.
The great reformers who have been humanity's vanguard have drawn the people to the world of human purity. The people too did not submit to these leaders in the way tyrants and strongmen are obeyed. Man takes to the path of merit and edification voluntarily and out of his free will and love for sublimity, and he refrains from carrying out some of his carnal impulses without confronting any psychic complex. It is with voluntarily zeal and enthusiasm that he responds to his sublime human feelings and performs goodly services which have not been forced upon him by custom, religion and society.
These are facts which show that man's inner psychic reality is not made up of a dark, pleasure-seeking principle pursuing merely the fulfilment of base desires; rather there is also grounded in him the urge for the highest good. There is a principle within him that is an independent source of virtuous actions and conduct. It is the conscience that reminds him that everything in life is not to be sought for selfish ends and that life is not mere pursuit of desires.
There are many individuals in the world who consider a life devoid of conscience to be a disgrace and an affront to their personal dignity as human beings. They are prepared to forego life and embrace death but are not ready to violate their conscience. When they perform a good deed by following their inner impulse, they have such a profound feeling of its worth and beauty that they would not be prepared to exchange the value of that moment of life for the entire world.
Had the foundation of man's personality been a subjective principle of an infantile character in which the pursuit of pleasure and avoidance of pain are the only functions that count, man's science and industry would not have attained such a level of progress and development.
The Domain and Role of Conscience
Conscience seldom makes any error in its judgements. The various errors of human beings in their social life either result from the errors of reason and the senses or are a consequence of the conscience losing its power of resistance against violent impulses.
Therefore, the numerous errors observed in the different walks of human life are not related to any weakness or misjudgement on behalf of conscience, because this innate faculty does not play any role outside its domain of activity. Conscience examines the conclusions and data provided by reason and the sensory faculties and its judgement is based on these.
A person with a pure and wholesome nature is repelled by crime and sin. Nevertheless it is possible that under the influence of certain factors he may become tainted by sin and vice and these may cast a shadow of shame and guilt over him. But after the offence has been committed once man turns to himself and consults the sublimest light within him, he realises the vicious character of that which happened and a burning flame leaps up from the depths of his being. A painful feeling of guilt and shame envelops his entire being. This is what is called conscience, which censures the offender even after he has been punished and torments him continually with the lashes of regret.
Conscience is not only a reliable guide in the course of life, it is a just and honest witness over man's conduct that keeps a watch over it and declares what it observes. A person may say with the tongue something which is the opposite of that which is in his heart, or he may hide his secret thoughts by controlling his apparent movements. But he has no power to silence the voice of his conscience or to stop it from reproaching him. Conscience cannot be deceived. It may be possible to elude it through some mental deception or trick or even to put it to sleep for a time. But once it wakes up and studies the sinful record of one's deeds, it declares with perfect candidness the ugly character of his vicious conduct and flogs him severely with the whip of guilt and regret.
A human being loves nothing more dearly than its own 'self'. One who suffers the most painful torture of guilt is in fact one who has been disowned and abandoned by his own 'self'. He comes to feel as if his crime and sin were a fire that consumes his being in its fierce flames. Hence conscience is the most effective agent in avoiding crime and sin.
If the intensity of the pangs of conscience that he suffers were beyond his power and tolerance, a feeling of anxiety and agitation fills all his conscious state, overshadows all other feelings of satisfaction. The tormenting pressure of the conscience in some cases disturbs the normal course of the person's psychic activities and give rise to pathological conditions. The study of psychic tensions in some cases of dementia that have been studied show that such persons are those who lost their sanity and rational faculties as a result of the shattering torment and pressure of conscience resulting from commission of crimes and sins and have fallen into the furnace of guilt and regret.
At times one's improper wishes and impulses are so strong that man wants to deceive his conscience and to stall its activity. It is a marvellous characteristic of the conscience that it can put up a steadfast resistance against powerful impulses and fight against them. As long as there occurs no failure in its resistance to the pressure of instincts, it carries on its effort and does not neglect its duty.
Henri Baruk says:
Conscience is strong in its persistence, and even when its light becomes so dim that it ceases to be visible it remains more or less vigilant and aware. And even at times when its light can be perceived with difficulty, it can, all of a sudden, begin to shine with a dazzling brilliance. 
Ultimately, everyone who has disobeyed his conscience and deviated from the course of nature has always faced mental torment and anxiety. On the contrary, one who heeds the warnings of the conscience and obeys its commands finds mental peace and tranquillity, the peace and tranquillity in whose search the misguided run after every mirage.
The Qur'an and the Voice of Nature
Today many scientists reject Freud's view and consider the conscience to be an innate part of man's nature. The thinkers who have employed the powers of sound and active intellect for acquiring the knowledge of man and the universe have affirmed the innate phenomenon of conscience. They have been led to the conviction that inclination toward virtue and repulsion from vice has natural roots in our being, that the system of creation has placed this blessed asset in the innate nature of every human being.
Here, along with some relevant verses of the Glorious Qur'an, we shall cite the views of some Western thinkers and scholars concerning this matter.
The Holy Qur'an considers man's inner faculty of discrimination between good and evil, virtue and vice as a Divine inspiration invested in his being.
By the soul, and That which shaped it and inspired it to lewdness and godfearing! (91:7-8)
Jean Jacques Rousseau writes:
Cast your eyes over every nation of the world; peruse every volume of its history; in the midst of all these strange and cruel forms of worship, among this amazing variety of manners and customs, you will everywhere find the same ideas of right and justice, everywhere the same principles of morality, the same ideas of good and evil.... There is therefore at the bottom of our hearts an innate principle of justice and virtue, by which, in spite of our maxims, we judge our own actions or those of others to be good or evil, and it is this principle that I call conscience...
Self-interest, so they say, induces each of us to agree for the common good. But how is it that the good man consents to this to his own hurt? Does a man go to death from self-interest? No doubt each man acts for his own good, but if there is no such thing as moral good to be taken into consideration, self-interest will only enable you to account for the deeds of the wicked; possibly you will not attempt to do more. A philosophy which could find no place for good deeds would be too detestable.... If such doctrines ever took root among us, the voice of nature, together with the voice of reason, would constantly protest against them, till no adherent of such teaching would plead an honest excuse for his partisanship...
The decrees of conscience are not judgements but feelings. Although all our ideas come from without, the feelings by which they are weighed are within us, and it is by these feelings alone that we perceive fitness or unfitness of things in relation to ourselves, which lead us to seek or shun these things.... To know good is not to love it; this knowledge is not innate in man, but as soon as his reason leads him to perceive it, his conscience impels him to love it, and it is this feeling which is innate...
Conscience! Conscience! Divine instinct, immortal voice from heaven, sure guide for a creature ignorant and finite indeed, yet intelligent and free; infallible judge of good and evil, making man like to God! In thee consists the excellence of man's nature and the morality of his actions; apart from thee, I find nothing in myself to raise me above the beasts- nothing but the sad privilege of wandering from one error to another, by the help of an unbridled understanding and a reason which knows no principle.
Thanks heaven we have got rid of all that alarming show of philosophy; we may be men without being scholars; now that we need not spend our life in the study of morality, we have found a less costly and surer guide through this vast labyrinth of human thought. But it is not enough to be aware that there is such a guide. We must know her and follow her. If she speaks to all hearts, how is it that so few give heed to her voice? She speaks to us in the language of nature, and everything leads us to forget that tongue. Conscience is timid, she loves peace and retirement; she is startled by noise and numbers; the prejudices from which she is said to arise are her worst enemies. She flees before them or she is silent; their noisy voices drown her words so that she cannot get a hearing; fanaticism dares to counterfeit her voice and to inspire crimes in her name. She is discouraged by ill-treatment; she no longer speaks to us, no longer answers to our call; when she has been scorned so long, it is hard to recall her as it was to banish her. 
Prof. Friedman says:
The voice of conscience is not a product of education or training or some other agency; rather, it is a part of the human personality. Whoever that rises to a high and distinguished position in society or becomes a standard-bearer of humanity, it is the voice of his conscience that guides him towards virtue and piety. 
A psychologist says:
Conscience is not a contrived reaction but a most profound agent inherent in the human nature. Despite various kinds of repressive efforts, men cannot silence or expunge the conscience. Moreover, the stability and extraordinary persistence of conscience, even in severe illnesses and in the course of madness and psychic disorders, and its survival even after the dimming of the light of intelligence, bear testimony, as said earlier, to its greatly significant and prominent position in the human psyche.
Some scientists ask themselves whether conscience is not a product of education and upbringing or that of religion. But it must be pointed out that salient features of this conscience have been found in primitive rituals. The expression of awe and dismay accompanying the seeking of forgiveness in these primitive tribes and also in many idol-worshipping peoples bear witness to the ancient character of conscience which has been with man since his beginnings. A denial of this fact is tantamount to utter failure in understanding the human psyche. 
The Holy Qur'an declares:
Have We not appointed to him two eyes, and a tongue, and two lips, and guided him concerning the two highways (of goodness and virtue and of evil and vice) ? (90:8-10)
We created man of a sperm-drop, a mingling, trying him; and We made him hearing, seeing. (76:2)
Samuel Smiles writes:
Conscience is that peculiar faculty of the soul which may be called the religious instinct. It first reveals itself when we become aware of the strife between a higher and a lower nature within us-of spirit warring against flesh-of good striving for the mastery over evil... To enjoy spiritual freedom of the highest kind, the mind must have been awakened by knowledge. As the mind has become enlightened, and conscience shows its power, the responsibility of man is increased...
Conscience is permanent and universal. It is the very essence of individual character. It gives a man self-control- the power of resisting temptations and defying them.... The only comprehensive and SUst;0ined exercise of self-control is to be attained through the ascendancy of conscience-in the sense of duty performed. It is; conscience alone which sets a man on his feet, frees him from the dominions of his own passions an propensities. It places him in relation to the best interests of his kind. The truest source of enjoyment is found in the paths of duty alone. Enjoyment will come as the unbidden sweetener of labour, and crown every right work. At its fullest growth, conscience bids men to whatever makes them happy in the highest sense, and forbear whatever makes them unhappy.... Without conscience, a man can have no higher principle of action than pleasure.... A race so constituted, with intellect and 1passions such as man possesses, and without the paramount influence of conscience to govern their deeds, would soon be consigned to utter anarchy, and terminate in mutual destruction. The greatest intellectual power may exist without a particle of magnanimity. The later comes from the highest power in mans mind-conscience, and from the highest faculty, reason, and capacity for faith- that by which man is capable of apprehending more than the senses supply.... The great lesson to be learnt is, that man must strengthen himself to perform his duty and do what is right, seeking his happiness and inward peace in objects that cannot be taken away from his. Conscience is the conflict by which we get the mastery over our own failings. It is a silent working of the inner man, bat which he proves his peculiar power of the will and spirit of God. 
The Qur'an declares:
I swear by the Day of Resurrection I swear by the reproachful soul. (75:1-2)
In this verse the inner cry of reproach and blame that arises from the depths of man's conscience has been called 'the reproachful soul' (al-nafs al-lawwamah). This is the same inner faculty which the psychologists called 'conscience'.
Prof. Otto Friedman writes:
Someone may spend many hours drinking wine in a bar or while away his time on the gambling table or engage in playing tennis. In any case, while he is occupied with all such diversions he might have an inner feeling of disquiet which continuously torments him and deprives him from drawing any pleasure from his pastime. An inner voice reproaches him that you are wasting away the hours of your life. This voice constantly echoes in his conscience.
On the other hand, instead of engagement in such pastimes the thought may occur to one that it would be much better if he engages in the training of his children or tending his garden and plants. It is here that his conscience guides him towards good actions which are useful for himself as well as beneficial for others. It is here that one always keeps on comparing himself with others and his conscience keeps on reproaching him. The greater and the steadier one's obedience to the voice of conscience, the proportionately greater will be his creative power and spiritual strength and the greater his zeal and vigour in life. And the lesser is one's attention to the voice of conscience, to the same extent he will be more violent and unrestrained. 
The Holy Prophet, may God bless him and his Household,
One who is overwhelmed by self-reproach loses all peace. 
It may happen that one loses his equilibrium in a moment of carelessness and his base impulses get the better of him. As a consequence he is rendered wretched and miserable and its regret and shame remains with him for a lifetime. Imam 'Ali, may peace be upon him, said:
How often does an hour of pleasure leave behind a long-lasting misery. 
Human societies in all ages have benefited from the inner agency of conscience in times of need. Individuals who are devoid of the moral feeling, for whom virtue and vice have no significance and who see pursuit of pleasure, food and lust as the purpose of life are like pieces of straw carried away by the flood of animal instincts and have no credibility or standing in any society, nation or community. When someone is trusted with a job, the presence of conscience is the presumed guarantee of its being carried out. There should be a good measure of confidence that he will act according to his duty. Otherwise it is unwise to delegate a task to someone whose conduct is suspect from the viewpoint of conscience or opposed to conscientious behaviour.
Islam has paid special attention to conscience and it bases the efforts at the improvement and betterment of social conduct on the individual's conscience. Islam tries to convince individuals to place a watchman in their inner souls which may restrain them from committing aggression and offence against others even in conditions of hostility and anger. The Qur'an warns human being in these words:
Let not detestation for a people move you to commit in justice. Be equitable-that is nearer to god-fearing. (5:8)
Accordingly no one has the right to aggress against others or violate the rights of others in any circumstances whatsoever. Positive law with the limited means at its disposal tries to restrain the human being from outside from committing acts of offence. But Islam lays great importance on cultivating and nurturing the conscience of individuals. With a developed conscience individuals themselves perceive the necessity of refraining from certain actions so that they may achieve spiritual edification and salvation. Without doubt, this kind of self-restraint motivated by religious faith and moral sense offers a surer means and a shorter way to the goal.
In the view of Islam the attainment of the higher goals of life is possible only through co-operation and mutual love between individual human beings. It invites the people to these virtues and asks them to base their relations on co-operation and love. In the light of such a teaching, every one feels that his existence as a human being is like a lamp that lights up the horizons of humanity when he, happily and without any reservations, extends his co-operation and love to others.
Imam al-Sadiq, may peace be upon him, reports the Noble Prophet, may God bless him and his Household, as having said:
It is the duty of every person to observe the seven rights of his brother in faith: (1) that one should not fail to show him respect and reverence; (2) one should really love him from the bottom of one's heart; (3) one should share one's belongings with him equally; (4) one must refrain from backbiting him and mentioning unseemly things about him in his absence; (5) one should visit him when he falls ill; (6) one should attend his funeral on his death; (7) one should not mention him except kindly after his death. 
Man listens to the summons of nature and discriminates virtue from vice when there isn't anything to obstruct the course of nature. A conscience in bondage and deprived of its free movement by the weighty chains of lust and position and power seeking impulses, cannot manifest its real character and be a trustworthy judge. Thus during crises of war and revolution and such extraordinary conditions conscience suffers terrible blows and its activity comes to a standstill. In such circumstances perverse ideas and doctrines emerge as the most potent dynamic force and the suppression of the collective conscience results in irremediable losses and harms for mankind.
There is a great difference between a conscientious person and an unconscientious one; this difference is even greater than the one that separates man from other creatures. If fire with its quality, which is to burn, burns a human body, it is a consequence of its essential nature. It has no consciousness that which it burns is a living creature, a human being that intensely feels the torment of burning. But whatever an unconscientious person does is done with knowledge and consciousness. Cruelty, injustice and suffering inflicted by men on other human beings are acts performed consciously.
One of the things alters man's primordial nature and casts dark shadows on the luminous face of pure nature is repetition of sin. A brutal criminal commits many terrible crimes without feeling any psychic torment for his ugly conduct. Such a sadistic condition is something quite exceptional.
Society can attain social justice only when individuals accept an inner agent that may act as a judge and invigilator over their acts and comply with its commands. If all people in a real social unit that gives meaning to their humanity possess a common and identical ethos, that not only brings about a perfect condition of coexistence, but makes them like parts of an organism and links of a mechanism.
The Bedrock of Reason and Conscience
When the rebellious impulses try to undermine the role of reason and conscience and make man a captive of lusts, faith turns out to be the best support for relying upon. Faith is the greatest support and foothold of conscience and reason. With its support reason and conscience acquire the capacity to suppress rebellious instincts in all circumstances, resist the hostile pressure of desires and to overcome any kind of dangerous inclination. A human being armed with the weapon of faith is one who, in the words of the Qur'an, "has laid hold of the most firm handhold that can never break.'' 
The function of theoretical reason on which metaphysics, natural science and mathematics are based, is to make judgements concerning reality. However, it is practical reason that forms the basis of the sciences of life and its function is to form judgements concerning the duties and responsibilities of man. The path and approach selected by the human being in life is related to the character of judgements made by practical reason.
One of the important factors that gives clarity of vision to the intellect is godfearing (taqwa). The claim that godfearing illuminates the intellect and opens the window of wisdom before man is a matter that does not relate to the theoretical intellect. It is with the means of godfearing that man is able to discern the correct way of living and discover his own ailments and their remedies.
Since the domain of action of the practical intellect is the same as the realm of desires, impulses, and passions, their unbridled violence has a decisive effect on man's practical intellect and thought which have the function of forming clear conceptions of duty and that which is right or wrong. The uncontrolled passions raise a dense mist that obstructs the light of the lamp of the intellect. In the words of Hafiz Shirazi:
The beloved's beauty has neither a veil nor a curtain before it, but,
The dusts of the road must be made to settle before the sight may work.
In Islamic teachings desire and passion have been considered hostile to the intellect because their hold weakens the power of the intellect and neutralises its influence. The Noble Messenger, may God bless him and his Household, said:
Your worst enemy is the one between your two sides; 
Imam al-Sadiq, may peace be upon him, says:
Desire is the intellect's enemy.
The Commander of the Faithful, 'Ali, may peace be upon him, says:
Most of the falls of intellects occur under the lightning bolts of greed. 
When godfearing takes hold of the heart, it puts desires and passions in chains, making them docile and tractable. As a result of it the intellect becomes free and active. This shows the effectiveness of taqwa in enhancing the vision and clarity of the intellect.
The Noble Messenger, may God bless him and his Household, mentions the following characteristics while describing the qualities of men of faith:
Among the salient merits of a person possessing faith is that he does not violate the norms of justice on account of resentment for someone. His attachment for someone does not make him take a sinful course. He is not a transgressor and does not oppress others. He does not accept falsehood though it should come from a friend and does not deny his enemy's legitimate rights. 
Man is completely free to utilise the precious assets of reason and conscience that he has been endowed with and to benefit from them. However, his ultimate freedom lies in overcoming some of his natural desires; that is, when a part of his being- that is his reason and conscience-dominates the other part, consisting of the natural instincts.
Reason and conscience maintain their supremacy so long as there is no conflict between them and turbulent psychic impulses, which are easily kept under the control of these two faculties. These two have a greater power than external police authorities, for their orders are considered by the individual to be issued by himself and hence he cannot rebel against himself by refusing to comply with them.
However, a major difficulty arises when the domination of reason and conscience necessitates indifference to or repression of one of the inner instincts. In such a situation, in many cases, the resisting power of reason and conscience breaks down in front of the violent force of instinct. They are forced to withdraw leaving the field to the marauding forces of instincts. Whatever may be the conditions, man is always threatened by his desires and passions.
But the man with genuine faith in God, whose faith has enduring roots in the profound depths of his heart and who is specially attentive to religious aspects, governs his tumultuous instincts by relying on this faith. In dangerous moments of life and vis-à-vis the call of illegitimate desires he rejects his improper impulses, and, with perfect authority and power, puts up steadfast resistance against rebellious passions.
Sophistry and Rationalisation
Compliance with the edicts of reason and conscience and submission to the demands of justice and equity are not simple tasks. Hence many persons who should comply with the call of conscience, submit to the judgements of sound reason in their encounter with moral, religious and scientific duties and in confronting facts and realities, and overlook some of their egoistic interests, are tormented by acceptance of responsibility and the prospect of loss. This anguish, which results from the absence of real faith and moral courage, makes them suppress their conscience in the adversities of life. Thereafter, in order to escape psychic pressures, they resort to some kind of lame justification and rationalisation. Obviously when someone takes resort in this improper approach several times, the activity of the intellect suffers and is weakened. The person gradually gets habituated to sophistry and moves away from correct logical thinking. Then it takes the form of a negative habit and in the course of time emerges as an enduring personal quality.
Another group of people, in order to escape responsibility and to avoid confessing their mistakes, try to shift the responsibility for various matters and in regard to certain crucial situations of life on to others by finding justifications in their own favour, seeking to close the issue by a one-sided judgement. This kind of improper judgements are not a result of negligence and absence of attention to the subtleties of an issue. Practically all deviant persons, the terrible character of whose acts is beyond any doubt, take resort in various kinds of justification and inadmissible rationalisation in order to explain and justify their inhuman acts.
Dale Carnegie writes:
I have had some interesting correspondence with Warden Lawes of Sing Sing on this subject, and he declares that "few of the criminals in Sing Sing regard themselves as bad men. They are just as human as you and I. So they rationalise, they explain. They can tell you why they had to crack a safe or be quick on the trigger finger. Most of them attempt by a form of reasoning, fallacious or logical, to justify their anti-social acts even to themselves, consequently stoutly maintaining that they should never have been imprisoned at all."
If Al Capone, "Two Gun" Crowley, Dutch Schulz, the desperate men behind prison walls, don't blame themselves for anything-what about the people with whom you and I come in contact? 
At first every person has a feeling of guilt for having shelved the burden of responsibility or for violating moral and social norms. But the repetition of such mistakes and offences, by diminishing the feeling of the negative and vicious character of such acts, makes one accustomed to them. Thereafter, in all the crucial stages that follow, his psychic responses vis-à-vis the offence unconsciously lose their sensitivity and the person comes to have a perpetual feeling of immunity from inner anguish and torment.
The Noble Qur'an describes such wretched creatures who have lost their awake and sensitive intellect and conscience due to crime and the pursuit of selfish gain and have sunk so irretrievably in the slumber of neglect and the mire of decadence that nothing can make them think again properly and discern between good and evil, as being more astray and inferior than beasts:
They have hearts, but understand not with them; they have eyes, but perceive not with them they have ears, but they hear not with them. They are like cattle; nay, rather they are further astray. Those-they are the heedless. (7:179)
 Carrel, Alexis, Reflexions sur la conduite de la vie, Pers. trans., Rah-wa rasm-e zindagi, pp. 99-100.
.Al-Amidi, Ghurar al-hikam, p. 212.
. Al-Kulayni, al-Kafi, vol. 1, p. 16.
. Ibid., "kitab al-'aql wa al-jahl."
. Spinoza, Ethics, in Man and Spirit: The Speculative Philosophers; ed. by Saxe Commins and Robert N. Linscott, p. 175.
. Al-Saduq, Ma'ani al-akhbar, p. 160.
. Baruk, Henri, Psychoses et nervroses, Pers. trans., Bimariha-ye ruh wa sasabi (Tehran, 1343) by 'Abd al-Husayn Mirsipasi, p. 73.
. Rousseau, Jean Jacques, Emile, trans. by Babara Foxley (Everyman's Library, 1969), pp. 251-254.
. Friedman, Otto, Pers. trans., Rawanshi nasi dar khidmat-e siyasat, p. 32.
. Baruk, op. cit., pp. 67-68.
. Smiles, Samuel, Duty (London: John Murray, 1926), pp. 19, 20, 21.
. Friedman, Otto, op. cit., pp. 31-32.
. Nahj al-fasahah, p. 621.
. Al-Kulayni, op. cit., vol. 2, p. 451.
. Al-Majlisi, Bihar al-anwar, vol. 15, "kitab al-ishrah," p. 61.
. The Qur'an, 2:256.
. Nahj al- fasahah, p. 66.
.Al-Amidi, Ghuraral-hikam, p. 195.
. Al-Majlisi, Bihar al-anwar, vol. 15, p. 82.
. Carnegie, Dale, How to Win Friends (New York: Simon and Schustar Inc., 1937), p. 27.