This controversial literature, cultivated on a large scale, was designed to defend Judaism against calumny and abuse, rather than to convert a single Christian soul. Its aim was to open the eyes of Jews, so that ignorance or credulity might not lead them into the snares prepared for them. Doubtless it also desired to stir up the new-Christians, and to re-animate their Jewish spirit beneath the disguise they had assumed to save their lives. Hence the majority of the polemical writings of the day were merely vindications of Judaism from the old charges fulminated by Nicholas de Lyra a century before, or more recently by Geronimo de Santa Fé and others, and widely circulated by the Christian clergy. Solomon-Paul of Burgos, who had been appointed bishop of his native town, wrote, in his eighty-second year (1434, a year before his death), a venomous tract against Judaism—"Searching the Scriptures" (Scrutinium Scriptuarum)—in the form of a dialogue between a teacher and his pupil, the unbelieving Saul and the converted Paul. Solomon-Paul does not seem to have retained much of the wit which, according to Jewish and Christian panegyrists, had at one time distinguished him—it had probably become blunted amid the luxurious ease of the episcopal palace—for his tract, devoutly Christian and Catholic in tone, is pointless and dull. Another ex-rabbi who devoted himself to attacking Judaism was Juan de España, also called Juan the Old (at Toledo), a convert who in old age had embraced Christianity under the influence of Vincent Ferrer's proselytizing efforts. He wrote a treatise on his own conversion and a Christian commentary on the seventy-second Psalm, in both of which he asserted the genuineness of his change of creed, and urged the Jews to abjure their errors. How many weak-minded Jews must have been influenced by the zeal, earnest or hypocritical, of such men as these, belonging to their own race, and learned in their literature!
It is impossible to exaggerate the services of the men who, deeply impressed with the gravity of the crisis, threw themselves into the breach, with exhortations to their co-religionists to remain faithful to their creed. In defiance of the dangers which menaced them, they scattered their inspiriting discourses far and wide. Foremost among them were the men who had distinguished themselves at the Tortosa disputation by their unyielding attitude and their courage in withstanding the unjustifiable attacks upon the Talmud—Don Vidal (Ferrer) Ibn-Labi and Joseph Albo. The former drew up in Hebrew a refutation of Geronimo's impeachment of the Talmud (Kodesh ha-Kodashim), and the latter circulated, in Spanish, an account of a religious controversy he had sustained with an eminent church dignitary. Isaac ben Kalonymos, of a learned Provençal family named Nathan, who associated a great deal with learned Christians, and frequently had to defend his religious convictions, wrote two polemical works, one entitled "Correction of the False Teacher," directed against Geronimo's libelous essay, and the other, called "The Fortress," of unknown purpose. He also compiled a laborious work of reference intended to assist others in defending Judaism from attack. Isaac Nathan, in his intercourse with Christians, often had to listen to criticisms of Judaism, or evidences drawn from the Hebrew Bible, in favor of Christian dogmas, which he found were always based on false renderings of Hebrew words. To put an end to these illusory outgrowths of prevailing ignorance of the original text of the Scriptures, or, at least, to lighten the labors of his brethren in refuting them, he resolved to compile a comprehensive digest of the linguistic materials of the Bible, by which the actual meaning of each word should be made clear. According to the plan adopted, any one can ascertain, at a glance, both how often a certain word occurs in the Bible, and its varying meanings according to the contexts. The work thus undertaken by Isaac Nathan was of colossal scope, and occupied a long series of years (September, 1437–1445). It was a Bible concordance, that is, the verses were grouped alphabetically under the reference words according to roots and derivations. The existing Latin concordances served in a measure as models, although their purpose was the less ambitious one of assisting preachers to find texts. Isaac Nathan, who produced various other works, by this concordance rendered inestimable and lasting service to the study of the Bible, although his labor was of a purely mechanical kind. Originating from the temporary needs of the polemical situation, it has been, and will ever remain, a powerful weapon for ensuring the triumph of Judaism in its struggles with other religious systems.
The philosopher, Joseph Ibn-Shem Tob (born 1400, died a martyr 1460), who was a voluminous writer, a popular preacher, and a frequenter of the Castilian court, also entered the lists against Christianity to expose the fallacy and unreasonableness of its dogmas. In his frequent intercourse with Christians of distinction, both clerical and lay, he found it necessary to make himself thoroughly acquainted with Christian theology that he might adduce cogent arguments in reply to those who wished to convert him, or in his presence made the oft-reiterated statement of the falsity of Judaism. Occasionally a regular controversy in defense of his creed was forced upon him. The fruits of his studies and thought he committed to writing in the shape of a small treatise, entitled "Doubts of the Religion of Jesus," in which he criticised with unsparing logic the dogmas of Original Sin, Salvation, and Incarnation. Besides, he wrote, for the instruction of his brethren, a detailed commentary on Profiat Duran's satire on Christianity, and made available for them, by means of a Hebrew translation, Chasdaï Crescas' polemical work against the Christian religion, originally written in Spanish. Strange to say, the Spanish Jews preferred, as a rule, Hebrew books to those in the language of their adopted country.
Among the authors of polemical works against Christianity a contemporary of Joseph Ibn-Shem Tob deserves special mention. History has hitherto forgotten Chayim Ibn-Musa, from Bejar, in the neighborhood of Salamanca (born about 1390, died about 1460), a physician, versifier and writer, who had access to the Spanish court and the grandees through his medical skill, and so, frequent opportunities of discussing questions of doctrine with ecclesiastics and learned laymen. A colloquy preserved by Chayim Ibn-Musa illustrates the spirit which prevailed in Spain before the hateful Inquisition silenced all freedom of speech. A learned ecclesiastic once asked Ibn-Musa why, if Judaism, as he maintained, was the true faith, the Jews could not possess themselves of the Holy Land and Jerusalem? Ibn Musa replied that they had lost their country through the sins of their fathers, and could regain it only by perfect atonement and purgation. He, in turn, propounded a question: Why are the Christians no longer in possession of the Holy Sepulcher? and why does it, together with all the sites associated with the Passion, continue in the hands of Mahometan infidels, notwithstanding that Christians, by means of confession and absolution, and through the medium of the nearest available priest, can free themselves at any moment from sin? Before the ecclesiastic could bethink himself of a suitable reply, a knight, who had formerly been in Palestine, interposed: The Mahometans are the only people who deserve to possess the site of the Temple and the Holy Land, for neither Christians nor Jews hold houses of prayer in so much honor as they. The Christians, during the night before Easter (Vigils), perpetrate shameful abominations in the churches at Jerusalem, abandon themselves to debauchery, harbor thieves and murderers, and carry on bloody feuds within their precincts. They dishonor their character in the same way as the Jews profaned their Temple. Therefore, God, in His wisdom, has deprived the Jews and the Christians of the Holy City, and has intrusted it to the Mahometans, because, in their hands, it is safe from desecration. To his observation the Christian priest and the Jewish physician could oppose only abashed silence.
Chayim Ibn-Musa devoted himself to the task of discrediting the chief sources of the materials of Christian attacks on Judaism, the writings of the Franciscan Nicholas de Lyra. He not only refuted the assertions put forward in those works, but deprived them of the soil upon which they fed. The ever-recurring controversies between Jews and Christians led to no conclusions, and left each party in the belief that it had gained a victory, because they generally turned on secondary questions, the disputants never discussing fundamental premises, but wrangling, each from his undemonstrated basis. Chayim Ibn-Musa wished to introduce method into these controversies, and to lay down clear principles for the defense of Judaism. Accordingly, he drew up rules which, strictly observed, were bound to lead to a definite result. In the first place, he advised Jews invariably to hold fast in a disputation to the simple meaning of the Scriptures, always to take the context into account, and especially to avoid allegorical or symbolical methods of interpretation, which left Christian polemics free to introduce arbitrary theories. Further, Jewish disputants were to announce that they ascribed no authority in matters of belief either to the Chaldaic translation of the Bible (Targum) or to the Greek (Septuagint), these being the sources of the false proofs adduced by Christians. He counseled them to abandon even Agadic exegesis, and not to hesitate to declare that it had no weight in determining the doctrines of Judaism. These and similar rules Chayim Ibn-Musa applied to the writings of Nicholas de Lyra, successfully refuting them from beginning to end in a comprehensive work, justly entitled "Shield and Sword."
The anti-Christian polemical literature of this period was further enriched by two writers, father and son, living in Algiers, far removed from the scenes of the Christian propaganda. But Simon ben Zemach Duran and his son, Solomon Duran, were Spaniards by birth and education. In his philosophic exposition of Judaism, the former devoted a chapter to Christianity, maintaining, in answer to Christian and Mahometan objections, the inviolability of the Torah. This chapter, entitled "Bow and Buckler," and described as being "for defense and attack," proves the contention of older writers, and more recently of Profiat Duran, that Jesus' intention was not to abolish Judaism. The rabbi of Algiers exhibits extraordinarily wide acquaintance with the literature of the New Testament and thorough familiarity with church doctrine, combats each with weapons taken from its own arsenal, and criticises unsparingly.
Solomon Duran I (born about 1400, died 1467), who succeeded his father in the Algerian rabbinate, combined with profound Talmudic knowledge a decided leaning towards a rationalistic apprehension of Judaism. Unlike his father and his ancestor, Nachmani, he was a sworn enemy of the Kabbala. During his father's lifetime and at his request, he wrote a refutation of the shameless, lying accusations brought against the Talmud by Geronimo de Santa Fé. In an exhaustive treatise ("Letter on the Conflict of Duties") he deals sharply with Geronimo's sallies. He repels the accusation that the Talmud teaches lewdness, and proves that it really inculcates extreme continence. Jews who regulate their lives according to Talmudical prescriptions scrupulously abstain from carnal sins, holding them in great abhorrence, and pointing with scorn at persons guilty of them. How, asks Solomon Duran, can Christians reproach Jews with unchastity—they, whose holiest men daily commit sins which dare not be mentioned to modest ears, and which have become proverbial as "Monk's sin" (peccato dei frati).
Religious philosophy, which had been raised to the perfection of a science only by Jewish-Spanish thinkers, had its last cultivators in Spain during this period. The same men who protected Judaism against the onslaughts of Christianity defended it against benighted Jews who wished to banish light, and, like the Dominicans, desired to establish blind faith in the place of reason and judgment. Zealots like Shem Tob Ibn-Shem Tob and others, biased by their narrow Talmudical education, and misled by the Kabbala, saw in scientific inquiry a byroad to heresy. Perceiving that for the most part cultivated Jews succumbed to the proselytizing efforts of Vincent Ferrer and Pope Benedict, men of the stamp of Shem Tob were confirmed in their belief that philosophic culture, nay, reflection on a religious topic, irretrievably lead to apostasy. The logical result of religious impeachment of science was the condemnation of Maimuni and all the Jewish thinkers who had allowed reason to have weight in religious questions. Against this form of bigotry Joseph Albo entered the lists with a complete religio-philosophical work (Ikkarim, "fundamental teachings"), in which he attempted to separate the essential doctrines of Judaism from the non-essential, and to fix the boundary line between belief and heresy.
Joseph Albo (born about 1380, died about 1444), of Monreal, one of the principal representatives of Judaism at the Tortosa disputation, who, probably through the intolerance of Pope Benedict, had emigrated to Soria, was a physician and a pupil of Chasdaï Crescas, hence well acquainted with the physical sciences and the philosophic thought of his time. Although a strict adherent of Talmudical Judaism, he was, like his teacher, not averse to philosophic ideas. Indeed, he tried to reconcile them, without, of course, permitting Judaism to yield a jot to philosophy. Albo had not, however, the profundity of his teacher; as a thinker he was superficial, commonplace, and incapable of writing with logical sequence. On the advice of his friends, he undertook to investigate in how far freedom of inquiry in religious matters was possible within the limits of Judaism. At the same time he wished to fix the number of articles of faith and to decide the question whether the number thirteen adopted by Maimuni was correct, or whether it could be increased or lessened without justly bringing a charge of heresy on him who made the change. Thus originated his religio-philosophical system, the last on Spanish soil. Albo's style differs widely from that of his predecessors. He was a preacher—one of the cleverest and most graceful—and this circumstance exercised marked influence on his method of exposition. It is easy, comprehensible, popular and captivating. Albo has the knack of explaining every philosophic idea by a striking illustration, and of developing it by skillful employment of Bible verses and Agadic aphorisms. What his style thus gained, on the one hand, in intelligibility and popularity, it lost, on the other, through a certain redundancy and shallowness.
It is a remarkable fact that Albo, who thought that he was developing his religio-philosophical system exclusively in the native spirit of Judaism, placed at its head a principle of indubitably Christian origin; so powerfully do surroundings affect even those who exert themselves to throw off such influence. The religious philosopher of Soria propounded as his fundamental idea that salvation was the whole aim of man in this life, and that Judaism strongly emphasized this aspect of religion. His teacher, Chasdaï Crescas, and others, had considered man's aim the bliss of the future life, to be found in proximity to the Deity and in the union of the soul with the all-pervading spirit of God. According to Albo highest happiness consists not so much in the exaltation of the soul as in its salvation. That is the nucleus of Albo's religio-philosophical system. Man attains only after death the perfection for which he is destined by God; for this higher life his mundane existence is but a preparation. How can he best utilize his term of preparation? There are three kinds of institutions for the reclamation of man from barbarism and his advancement to civilization. The first is Natural Law, a sort of social compact to abstain from theft, rapine and homicide; the second is State Legislation, which cares for order and morals; and the third is Philosophical Law, which aims at promoting the enduring happiness of man, or, at least, at removing obstacles in the way of its realization. All these institutions, even when highly developed, are powerless to assist the real welfare of man, the redemption of his soul, his beatitude; for they concern themselves only with actions, with proper conduct, but do nothing to inculcate the views or supply the principles which are to be the mainsprings of action. If the highest aim of man be eternal life or beatitude after death, then there must be a Divine Legislation, without which man in this world must always be groping in darkness and missing his highest destiny. This Divine Legislation must supply all the perfections lacking in its mundane counterpart. It must have for its postulate a perfect God, who both wishes and is able to promote the redemption of man; it must further bear witness to the certainty that this God has revealed an unalterable Law calculated to secure the happiness of man; and finally it must appoint a suitable requital for actions and intentions. Hence this Divine Legislation has three fundamental principles: the Existence of God, the Revelation of His Will, and just Retribution after Death. These are the three pillars on which it rests, and it requires none other.