The conflict between faith and doubt
This is the central philosophical conflict in the novel, and is embodied in the characters of Zosima and Alyosha (faith), and Ivan and Fyodor Pavlovich (doubt). The conflict is a consequence of free will, in that it arises from the fact that man is free to believe in God or not.
Dostoevsky shows that faith and doubt give rise to very different types of behavior. Zosima and Alyosha's love of God overflows into love of mankind. They practice active love, whereby their main concern is to love, forgive and refrain from judging their fellow man, and to alleviate his suffering where possible.
Ivan, relying on logic, doubts the existence of God and the immortality of the soul. He thinks that the only reason why people are good is fear of the consequences of doing wrong in the afterlife. Hence, because he rejects God, he also rejects the moral categories of good and evil and preaches the message that "everything is permitted." However, Ivan does not really believe what he preaches: he is a deeply moral person and is disgusted by those people who live out the doctrine that "everything is permitted," notably Fyodor Pavlovich and Smerdyakov. Thus there is division in Ivan's soul. His lack of faith in God spills over into a lack of faith in himself and his fellow human beings. This in turn leads to a cold attitude and an inability to recognize and accept love when it offers itself (for example, from Alyosha and Katerina).
Both Alyosha and Ivan find their viewpoints challenged, and both face a crisis of soul. Alyosha's occurs when Zosima dies and his body corrupts quickly, leading to widespread doubts about his holiness. Alyosha is briefly plunged into despair, but recovers when he meets Grushenka and unexpectedly feels a wave of love and trust pass between them.
Ivan's crisis occurs when he witnesses the logical conclusion of his doctrine of "everything is permitted": Smerdyakov's murder of Fyodor Pavlovich. Ivan realizes that he is partly responsible for the murder. This is his first experience of the truth of Zosima's teaching that each person is responsible for everyone else's sins. In the men of faith, Zosima and Alyosha, this knowledge of connectedness prompts love and forgiveness towards their fellow man. The doubting Ivan, however, lacks any sustaining faith in, or love for, God or man. His sudden realization of his connectedness with the murderer Smerdyakov overwhelms him with guilt and despair. The intellect on which he has relied deserts him and he begins to go insane.
Ivan's collapse (along with the appalling fates of Fyodor Pavlovich and Smerdyakov) is Dostoevsky's indictment of the philosophy of doubt, which, he suggests, ends in chaos and suffering. It is significant that at the novel's close, the chief hope of Ivan's recovery and redemption lies in the love that Katerina is finally able to express for him.
Frequently in The Brothers Karamazov, Dostoevsky emphasizes that in free will, God has given mankind a great responsibility, even a burden. Everyone is free to believe in God or not, and to do good or not. In every moment, man constantly has the ability to choose evil. It is not part of God's plan to provide convenient miracles that force doubters to believe or to respond to life's challenges in certain ways. Free will makes mankind's path more difficult, painful and dangerous, but it is necessary if man is to evolve beyond the state of childhood.
The part of the novel that most explicitly examines free will is Ivan's poem, "The Grand Inquisitor," in Book V. The Grand Inquisitor argues that when Christ rejected Satan's three temptations to perform miracles, he robbed man of the certainties of life (enough food, a rigid power structure, and a God who provides miracles in order to force people to believe) and instead, gave him free will. But free will is as much a curse as a blessing, since most people are not strong enough to refuse earthly securities in return for heavenly glory. The Grand Inquisitor allies himself with Satan out of compassion for the weakness of mankind, to give man back the certainties of an all-powerful church that provides miracles on demand and a rigid social structure that enslaves man but ensures that he has enough food and shelter. In the Inquisitor's world, man's free will has been sacrificed in favor of social order and contentment. Through his character of the Inquisitor, Ivan suggests that man would be better off being enslaved and secure rather than free and making the appalling mistakes that lead to the suffering of innocents.
Though the Inquisitor's argument is convincing on the level of logic, it shows the emptiness and lack of faith in mankind that lies at the center of Ivan's philosophy and that eventually makes him lose his reason. Within the poem, Christ's response to the Inquisitor is simply to kiss him on the lips - a profound gesture of love. Throughout the novel, Dostoevsky shows that to choose a life of love and faith, exemplified by Zosima and Alyosha, is the only constructive answer to the evil and suffering that spring from the exercise of free will. It is by no means the easy option, as is shown by Alyosha's crisis of soul after Zosima's death, but it is the humane one.
Zosima teaches that every person is responsible for everyone else's sins. This is why it is so important for people not to judge others but to practice active love, even regarding criminals, as through love, the criminal may repent and be reformed. Alyosha takes this lesson to heart in that whenever he sees anyone suffering, he intervenes and does his best to help. It would be foreign to his nature to see someone suffering and walk on by.
In Book V, in stark contrast with Zosima's and Alyosha's view, two characters deny responsibility for their fellow man: Smerdyakov tells Alyosha that he is not Dmitri's keeper; and Ivan says the same thing to Alyosha about Dmitri. They mean that if Dmitri chooses to kill his father, they cannot do anything about it. Fyodor Pavlovich also expresses this idea in his utter failure to act as a father to his sons.
Smerdyakov's and Ivan's insistence that they are not their brother's keepers echoes the biblical exchange between Cain and God about Abel, the brother whom Cain murdered: "And the Lord said unto Cain, Where is Abel thy brother? And he said, I know not: Am I my brother's keeper? And he [God] said, What hast thou done? The voice of thy brother's blood crieth unto me from the ground" (Genesis 4: 9-10).
It is no accident that Ivan, Smerdyakov and Fyodor Pavlovich express the opposite of Zosima's teachings with regard to moral responsibility. They all doubt God and the immortality of the soul, and draw the conclusion that the moral categories of good and evil do not exist. In other words, "everything is permitted," every person can do as he wishes, and others should not interfere. This logical stance is backed up by the emotional factor that none of these men is a lover of humanity. Though Ivan loves humanity in the abstract, he is repulsed by, and distant to, individuals. Hence to Dostoevsky, a person who denies responsibility for his fellow man's sins is someone who fails to love.
The moral of the Cain and Abel story, and the moral of The Brothers Karamazov is that each person is indeed his brother's keeper - a realization that comes to Ivan just before Dmitri's trial and drives him insane. By leaving town on the day of the murder, Ivan helped facilitate Smerdyakov's crime; even Alyosha played a part when, taken up with concern about the dying Zosima, he chose to return to the monastery rather than look for Dmitri.
The novel examines the man-made criminal justice system and finds it wanting, most notably in Ivan's "The Grand Inquisitor" poem, Zosima's anecdote of the philanthropist, and in Dmitri's trial. In the first example, the innocent Christ is jailed by the Grand Inquisitor for the 'crime' of setting man free. That story is ironically reversed in the case of the wife-murdering philanthropist who escapes detection. In Dmitri's trial, untrue statements are made by the prosecution and defense, and the jury wrongly proclaims Dmitri's guilt.
Dmitri's trial provides Dostoevsky with an opportunity to satirize the criminal justice system in detail. He emphasizes how any decision can be formed on the flimsy basis of circumstantial evidence, unreliable witnesses and even the hobbies of prosecuting lawyers (such as the interesting, but utterly mistaken, psychological insights of prosecutor Kirillovich).
Man-made justice, then, is shown to be unjust and unable to grasp the truth of any situation. It is also unable to reform the criminal, who is likely to respond to any punishment by further alienating himself from society. This is clear from the example of Kolya's ill-judged punishment of Ilyusha, which succeeds only in turning a well-meaning boy into a menace to society. As Zosima says in Book II, Chapter 5, the only effective punishment is "the acknowledgement of one's own conscience." This alone can frighten the criminal enough to make him repent and reform. Zosima's words are proven by the cases of the philanthropist and Dmitri, who are wrongly judged by the criminal justice system but whose consciences provide effective punishment and sentences.
Redemption through suffering
When Zosima says that "the acknowledgement of one's own conscience" is the only effective punishment for doing wrong, he means that the person has to look within and face up to what he has done. This can entail great suffering. Repentance follows, and then reform. Several characters in The Brothers Karamazov endure periods of suffering in which they develop spiritually. An example is Grushenka, who becomes very ill after Dmitri's trial and conviction (illness is often used in this novel as a symbol of spiritual purification). In the course of the novel, she undergoes a transformation from a frivolous woman who plays with men's emotions to a serious, loving woman who fully intends to accompany Dmitri in exile and till the soil by his side. Her growth is partly due to her acceptance of responsibility for her part in the murder, the framing of Dmitri for the crime, and the verdict of guilt that is passed upon him.
The most obvious example of redemption through suffering is Dmitri. His redemption takes place as a result of his realization that though he did not murder his father, his intemperate passions partly enabled the murder to take place. He is also conscious of his many other sins: lying to almost everyone, stealing from Katerina, beating up his father and Snegiryov, and so on. In addition, after his dream of "the wee one" (the suffering baby), he realizes that he is to some degree responsible for everyone else's sins. As his trial approaches, he has a vision of redeeming himself through the suffering of hard labor in Siberia. It is noteworthy that all these processes take place before the trial, which in comparison thoroughly fails in holding up a picture of truth to the defendant or in passing a just verdict. Thus Dostoevsky makes clear that examination of one's own conscience leads to a period of suffering, which in turn leads to redemption. No part of this process is achieved through the criminal justice system.
Two characters provide significant variations on the theme of redemption through suffering. The first character is Lise, who rejects marriage with a good man who loves her (Alyosha) in favor of envisioning a marriage with someone who will torture her. In a parody of the theme of redemption through suffering, she punishes herself for her own wickedness by shutting her finger in the door. This ridiculous act of self-mutilation shows that not all suffering is necessary or constructive. Lise does not learn or redeem herself through suffering; she simply makes her life, and the lives of those around her, needlessly miserable.
The second character is Katerina, who shares with Lise a talent for creating suffering. She loves Ivan, but for most of the novel cannot bring herself to admit it, as she is too bound up in acting the martyr by devoting herself to Dmitri, who does not love her. Her redemption begins when she cries out for Ivan in court - an act of spontaneous love that marks the end of her previous tortured and strained relations with Dmitri and Ivan. Her act is prompted by the ordeal of witnessing Ivan attempting to take responsibility for the murder in the witness box, thus saving his brother. Unfortunately, her testimony has the effect of further incriminating Dmitri. After the court case (according to Alyosha's belief), she feels overwhelmed by grief for her betrayal of Dmitri. Alyosha thinks that her pride is about to shatter, and he is right. Katerina forgives Dmitri and Grushenka, and sets about nursing Ivan in his illness, thereby fully accepting her love for him. As well as redeeming Katerina, the relationship seems likely to redeem Ivan, too.