Joseph's hard lot may be considered as typical of the decay of the method of teaching which depended on the power of memory. It heaps up the treasures of learning and tradition, guarding every atom of its hoard as painfully as a miser, and warns off all influences exerted by the employment of the intellect, as if they might obscure its mirror-like purity; but in an unlucky moment the store that has been laboriously collected suddenly vanishes; memory is extinguished, and there remain no means of recovering the lost treasures.
The Soranian school, the home of culture, also began to decline, through neglecting to further the development of the Law. After Chasda's death, the post of principal was held for twelve years (309–320) by Huna's son, Rabba or Rab Abba; but the studious youths were more strongly attracted by the rising star of the Pumbedithan Academy. For this reason Rabba's modesty is the only circumstance in connection with which any remembrance of him is retained. After the death of Rabba bar Huna, the Soranian Academy was deserted, and it was not frequented until half a century later, when it began to regain its lost renown.
After Joseph's death, the college was embarrassed as to whom it should appoint as his successor. There were four who seemed worthy to occupy this post, being all equally esteemed; they were Abayi, Raba, Zeïra II, and Rabba bar Matana. The college accordingly determined to vote for the one who should give the most striking answer, to which no objection could be offered, to a question that was raised. Abayi was victorious in this intellectual tournament, and was chosen as principal. Abayi, whose surname was Nachmani (born about 280, died 338), was an orphan; his father Kailil had died before, his mother immediately after, his birth. A governess took the place of his mother, while Rabba, the sagacious Amora of Pumbeditha, filled that of his father. In after-life, Abayi spoke with gratitude and emotion of his foster-mother, and gave her name to several healing medicaments. To his uncle Rabba, Abayi owed his knowledge of the Law and his skill in Talmudical dialectics. Like Raba, his contemporary Amora, he aroused great expectations during his early youth, and it used to be said of them, "The bud shows what the melon will be." Abayi appears to have possessed but a moderate fortune. Like the majority of the Babylonian teachers of the Law, however, he had a small field of his own, which he cultivated by the agency of a freeman. His character was mild and yielding, and he retained these qualities in his intercourse with the various classes of society. His maxim was: that man should be sagacious in the fear of God, gentle and conciliatory in his speech, and at peace with his brethren, with his relations, in fact, with all the world, even with the heathen abroad, so that he might be beloved and esteemed, and possess influence over his fellow-men. At this time opinions, words, and deeds, were still one and the same. Abayi's integrity was even acknowledged by such of the Samaritans as dwelt in Babylonia. Having once lost an ass which was found by some Samaritans, it was brought back by them to its owner, though he was not able to mention any special mark by which it could be recognized. "If thou wert not Nachmani," said they to him, "we should not have restored the ass even if it had borne some particular mark." Under Abayi's direction of the Pumbedithan Academy (333–338) the number of students diminished to about two hundred, and therefore in remembrance of the crowd of scholars who had flocked thither during the time of his predecessors, Rab and Huna, he called himself an "orphan of orphans." It was not that less interest and pleasure than formerly were now felt in study, but that Abayi possessed a rival in Raba, who had founded a school of his own in Machuza on the Tigris, whither he had attracted many students. Both of these teachers brought the Pumbedithan method to its greatest perfection. Rivaling one another in talent and ingenuity, they discovered answers to questions which Rabba and Joseph had been unable to solve.
The traditions which had been handed down no longer afforded material for discussion, every point which they presented having already been thoroughly elucidated; new themes were therefore propounded and solved by the help of recognized formulæ. These subtle Talmudical dialectics received the names of their most proficient adepts, and were known as the "Havayot (reflections) d'Abayi ve Raba."
Before his death, Abayi heard of the cruel persecutions to which his coreligionists in Judæa were subjected under Constantius. The fugitives who conveyed this sad news to Babylonia, also brought with them new Halachas, from the circle of which Jochanan was the head, and thus inspired the learned students of Babylonia with new vigor.
Abayi died in the prime of life (338). After his death, the office of principal was conferred upon Raba bar Joseph bar Chama of Machuza (born 299, died 352), without any discussion, as if this was expected as a matter of course. Raba was wealthy, talented and acute, but possessed his weak points, which caused him to be considered inferior to his fellow Amoraim, although he surpassed them in acuteness of intellect. He was well acquainted with his own character, and described himself in the following words: "I have always cherished three wishes, of which, while two have been fulfilled, the gratification of the third has not been vouchsafed to me. I desired Huna's learning and Chasda's wealth, and obtained both; but Rabba bar Huna's unassuming modesty was not allotted to me." Although he was superior to the majority of his fellow-countrymen, his character was tainted, nevertheless, with certain peculiarities of the Machuzans; he was luxurious, proud and overbearing, and although his fellow-countrymen did not enjoy the best of reputations in Babylonia, he flattered them to excess. He was exceedingly desirous of winning and retaining their favor. "When I became judge," he relates, "I was afraid that I should no longer retain the attachment of the Machuzans, but as they recognize my impartiality in giving judgment, all must either hate or all love me." Abayi seems to have reproved this tendency of Raba to sacrifice moral dignity for the acquisition of popular favor. "When a teacher of the Law," said he, "is too greatly beloved by his fellow-citizens, it is not because of his great merit, but on account of his indulgence, which causes him to refrain from calling attention to their vices, and from earnestly reprimanding them."
It has already been mentioned that the inhabitants of Machuza were descended for the most part from proselytes, for which reason the aristocratic Babylonian Jews forbore to contract marriages with them. As the Machuzans thus seemed to be at a loss how to obtain wives, Zeïra II declared in a public discourse that it was allowable for them to marry persons who had been born out of wedlock. This permission, however, implying as it did a sort of degradation of the Machuzans, was so offensive to their pride, that they almost stoned him to death with the fruits with which the booths were decorated (the incident occurring during the celebration of the feast of Tabernacles), just as King Alexander Jannæus had once been attacked in the outer court of the temple. Raba could hardly find words severe enough with which to blame Zeïra's candor: "Who would give utterance to so inconsiderate a decision in a community containing so many descendants of proselytes!" In order to enlist the favor of the populace still more strongly on his side, he demonstrated, in opposition to Zeïra's theory, that proselytes might marry even the daughters of priests, and he succeeded by this flattery in charming the Machuzans so greatly that they overwhelmed him with presents of silken stuffs. In after-times Raba attempted to restrict the equality which he had accorded somewhat too freely to the proselytes, probably on account of its having caused displeasure in various circles; at the same time he remarked that proselytes might ally themselves with bastard families. This decision having caused dissatisfaction, Raba appeased his fellow-countrymen with the following words: "I only meant well towards you, and leave you free to act either way."
Another of Raba's failings was that, although exceedingly wealthy, he was not entirely free from covetousness, which he allowed to become apparent on several occasions. A proselyte of Machuza, Issor by name, had deposited with Raba a sum of 12,000 sus (denars), in order to bequeath it to his son, who was being brought up as a student of the Law. Issor having fallen ill, Raba resolved to keep possession of this money as property to which there was no heir, a proselyte being unable to leave his fortune to a son born before his adoption of Judaism, as the Talmudical law does not recognize such offspring as a son. At all events, the principal of the schools—familiar as he was with all the intricacies of the Law—was determined to nullify Issor's disposal of his fortune in favor of his son. Meanwhile, another person who was equally well acquainted with the Law, suggested to the anxious father that, although he was prevented from making over the money in question to his son by will, he was, nevertheless, at liberty to do so by declaring before witnesses that the money belonged to the latter. Raba was greatly incensed at the man who offered this counsel, and complained as bitterly of this secret advice as if he had thereby been deprived of a lawfully acquired fortune. Raba's conduct also violated an accepted Halacha which treats of a similar case. According to this law, although a man is not obliged to hand over to such of the sons as may have become proselytes, the property committed to his keeping by a heathen, of which the latter had not otherwise disposed, an offense is, nevertheless, committed against the higher laws of morality by withholding it from them.
Another example of Raba's selfish conduct is afforded by the fact that he exacted a higher rent from the tenants of his fields than was customary in Babylonia. At times his behavior towards persons of slender means was marked by a harshness which was in glaring opposition to the doctrines of charity and pity, inculcated equally by the Halachas and the Scriptures.
The conduct of his brother Saurim was even more heartless; he posed as a moral censor, and whenever any of the poorer members of the community appeared to him not to be religious enough he made slaves of them, and compelled them to carry him about in his gilded litter. Even to this conduct Raba offered no objection, but sanctioned his brother's arbitrary proceedings by referring to a long-forgotten law, which countenanced the treatment of the Jews as slaves, in case they no longer lived in accordance with the Law.