Synthesized answer
The passages indicate that the public prosecutor, Breve, needs a conviction in every case because he is very ambitious and has firmly made up his mind to get on in his career. [Passage 5] states that he "had been public prosecutor but a short time" and "was very ambitious, and had firmly made up his mind to get on, and therefore thought it necessary to get a conviction whenever he prosecuted." This ambition is tied to his personal advancement, not to any specific legal or social principle.
Additionally, the prosecutor's approach to his speeches reflects a desire for personal recognition. He believes his speeches "should always have a social importance, like the celebrated speeches made by the advocates who have become distinguished" [Passage 2] and [Passage 4]. He is described as "very stupid by nature" but "self-confident and self-satisfied in the highest degree" [Passage 4], which further drives his need to succeed in each case. The passages do not mention any external pressure from superiors or the legal system to secure convictions; the motivation appears entirely self-serving and careerist.
Synthesized from the book passages below. Chat with the book on Feynman for follow-up.
From the book
gracefully swaying his body, “the fate of society is to a certain extent in your power. Your verdict will influence it. Grasp the full meaning of this crime, the danger that awaits society from those whom I may perhaps be permitted to call pathological individuals, such as Maslova. Guard it from infection; guard the innocent and strong elements of society from contagion or even destruction.” And as if himself overcome by the significance of the expected verdict, the public prosecutor sank into his chair, highly delighted with his speech. The sense of the speech, when divested of all…
uld always have a social importance, like the celebrated speeches made by the advocates who have become distinguished. True, the audience consisted of three women--a semptress, a cook, and Simeon’s sister--and a coachman; but this did not matter. The celebrities had begun in the same way. To be always at the height of his position, i.e., to penetrate into the depths of the psychological significance of crime and to discover the wounds of society, was one of the prosecutor’s principles. “You see before you, gentlemen of the jury, a crime characteristic, if I may so express myself, of…
ich case shall we take first, then?” “The poisoning case, I should say,” answered the secretary, with indifference. “All right; the poisoning case let it be,” said the president, thinking that he could get this case over by four o’clock, and then go away. “And Matthew Nikitich; has he come?” “Not yet.” “And Breve?” “He is here,” replied the secretary. “Then if you see him, please tell him that we begin with the poisoning case.” Breve was the public prosecutor, who was to read the indictment in this case. In the corridor the secretary met Breve, who, with up lifted…
dine, and show some mercy on the rest. But the public prosecutor showed mercy neither to himself nor to any one else. He was very stupid by nature, but, besides this, he had had the misfortune of finishing school with a gold medal and of receiving a reward for his essay on “Servitude” when studying Roman Law at the University, and was therefore self-confident and self-satisfied in the highest degree (his success with the ladies also conducing to this) and his stupidity had become extraordinary. When the word was given to him, he got up slowly, showing the whole of his graceful figure…
tand, pens, clean paper, and good, newly-cut pencils of different kinds. The public prosecutor came in with the judges. With his portfolio under one arm, and swinging the other, he hurriedly walked to his seat near the window, and was instantly absorbed in reading and looking through the papers, not wasting a single moment, in hope of being ready when the business commenced. He had been public prosecutor but a short time, and had only prosecuted four times before this. He was very ambitious, and had firmly made up his mind to get on, and therefore thought it necessary to get a…