Sefer HaIkkarim
Sefer HaIkkarim (Hebrew: ספר העיקרים "Book of Principles") is a fifteenth-century work by rabbi Joseph Albo, a student of Hasdai Crescas. It is an eclectic, popular work, whose central task is the exposition of the principles of Judaism. The work contains a number of internal contradictions. While most scholars see this as indicating Sefer HaIkkarim is an eclectic work, lacking originality and vision, recent scholars instead see this as one of Albo's methods for conveying esoteric messages. Principles of faith
His work is best known for its discussion of the Jewish principles of faith, in which he argues with other thinkers such as Maimonides. Albo stated that any religion (dat elohit), including Judaism, must have the following three fundamental principles, which he calls ikkarim (fundamentals) or ikarim kollelim (general fundamentals):
 belief in the existence of God
 belief in the revelation of God,
 belief in divine justice, as related to the idea of immortality. From these three principles, Albo posited that a religion must have eight derivative principles (shorashim [roots] or ikkarim peratiim [specific fundamentals]) which follow logically from the three fundamentals:
From the existence of God:
God's unity
God's incorporeality
God's timelessness
God's perfection: in God there can be neither weakness nor other defect. From the revelation of God:
God's prophecy
God's prophet authentication
From the reward and punishment of God:
God's omniscience
Reward and punishment, whether in this world or the World to Come

According to Albo, an individual who rejects one of either the 3 fundamental or the 8 derivative principles is called a "heretic" in Jewish sources. Similarly, a religion which rejects one of these 11 principles is a false religion. Albo argues that the theologies of both Christianity and Islam misunderstand one of the "fundamentals" and thus reject one of the "derivative principles", making them false religions. Whereas, according to him, Judaism contains a correct understanding of these principles. Albo also derives 6 "secondary principles" which a Jew should believe, but are not part of the fundamental or derivative principles. He calls these anafim (branches), as the "tree" of Judaism can stand without them (unlike the trunk or roots). These principles are:
Creation ex nihilo
The unique greatness of Moses' prophecy
The eternity of the Torah (i.e. that it will not be replaced by a different law)
That performing even one mitzvah entitles one to enter the World to Come (because otherwise, entering the World to Come would be harder after the Torah was given than beforehand via the basic Seven Laws of Noah, which would contradict the idea that the Torah is a beneficial gift to Jews). Resurrection
The messiah

Denying these principles, too, makes a Jew a heretic and disqualifies him from the World to Come, even though these principles are not necessary for the existence of religion. However, elsewhere in the work Albo says that denying the messiah did not make the Talmudic Rabbi Hillel into a heretic. Albo's work contains a number of internal contradictions, and this may be one of them. Distinctive features
Albo's three principles agree with Simeon ben Joseph of Lunel (i.e. Duran), but disagree with Maimonides' thirteen and Crescas' six. In the formulation of other articles of faith, the controversies to which the compilers had been exposed influenced both the selection of the specific principles to be accentuated, and the way that they were presented. Similarly in the case of Joseph Albo, his selection was made with a view to correct the scheme of Maimonides in those points where it seemed to support the contentions of the Christian dogmatists and controversialists. Maimonides himself had been influenced by a desire to obviate certain Christian and Muslim claims. His emphasis upon the absolute incorporeality of God finds its true light only when the Christian doctrine of the incarnation is borne in mind. His Messianic expectation, with the stress upon the constancy with which its future fulfillment is to be looked for, had also an anti-Christian bearing. But this very point, the Messianic dogma, had in turn soon become a source of anxiety to the Jews, forced to meet in public disputations the champions of the Church. Among the spokesmen of the Church were some converts from Judaism. These were not slow to urge this Messianic dogma of Maimonides as far as they might, to embarrass the defenders of Judaism. Before the time of Maimonides the question of the corporeality of the Messiah appears not to have been among the problems discussed in the polemics between the Church and the Jewish community. But half a century after him, when his Messianic doctrine had been accepted as one of the essential articles of the faith, it was this point that was pushed into the foreground of the discussions. Having participated in one of these public disputations, Albo must have become conscious of the embarrassment which the Maimonidean position could not but occasion to the defenders of Judaism. In his scheme, therefore, the Messiah is eliminated as an integral part of Jewish faith. In its stead he lays stress upon the doctrine of divine justice. The title of his book indicates his method at the outset. Basic to his investigation is the recognition that "human happiness is conditioned by knowledge and conduct." But "human intellect can not attain unto perfect knowledge and ethical conduct, since its power is limited and soon exhausted in the contemplation of the things the truth of which it would find; therefore, of necessity, there must be something above human intellect through which knowledge and conduct can attain to a degree of excellence that admits of no doubt." The insufficiency of human intellect postulates the necessity of divine guidance; and thus it is the duty of every person to know the God-given law. But to know it is possible only if one has established the true principles, without which there can be no divine law. Seeing that on this vital theme there are so much divergence, confusion, and shallowness, Albo resolves to erect a structure for the true religion. Religious flexibility
Albo finds opportunity to criticize the opinions of his predecessors, yet he takes pains to avoid heresy hunting. Accordingly, he endeavors to establish the boundary-lines between which Jewish skepticism may be exercised without risk of forfeiture of orthodoxy. His canon for distinguishing heterodoxy from orthodoxy is the recognition of the truth of the Torah. A remarkable latitude of interpretation is allowed. Albo rejects the assumption that creation ex nihilo is an essential implication of the belief in God. Albo freely criticizes Maimonides' thirteen principles of belief and Crescas' six principles. Albo states that neither Maimonides nor Crescas keeps in view his own fundamental criterion; namely, the absolute indispensability of a principle without which the trunk of the tree could not subsist; and on this score he rejects parts of their creeds. Other content
The book contains four sections. The first section explains his approach to the principles of faith. Sections 2, 3, and 4 are each ordered around one of his three fundamental principles. However, in addition to the discussions of principles of faith, the book contains many other subjects and sayings. According to Albo there are three kinds of law: natural law, conventional law, and divine law. Natural law is the same for all persons, times, and places; conventional law is ordered by a wise judge in accord with reason; divine law is given by God through a prophet. Albo's attitude toward meat eating is often quoted:
When the Torah was given to Israel... God prohibited some animals, which cause spiritual coarseness and filth [in those who eat them]. And the animals which were permitted, were permitted only to counteract the evil inclination.. eating meat was only permitted out of necessity... It is like wine; which even though it is good food and allowed to man, the Bible calls the Nazirite who avoid it "sacred". Publication and reception
Albo completed the Ikkarim in 1425 in Soria. The Ikkarim was not composed in its entirety at once. The first part was published as an independent work. It develops the gist of Albo's thought; and it was only when its publication brought down upon him a deluge of criticism that he felt compelled to add to it. In his preface to the second part Albo delivers a sermon on the subject of his critics: "He that would criticize a book should, above all, know the method employed by its author, and should judge all the passages on a certain subject as a whole." He castigates what he saw as the careless procedure of those passed judgment on an author without remembering this fundamental requirement of sound criticism. Albo's opponents did not handle him delicately. He was accused, among other things, of plagiarism. It was maintained that he appropriated the thoughts of his teacher Hasdai Crescas without giving him due credit. Examination of the evidence, however, does not substantiate the indictment. Crescas having been Albo's teacher, the similarities are only such as might be reasonably expected in the writings of both teacher and student. The first edition of the Ikkarim appeared at Soncino, 1485; it was published with a commentary under the title of Ohel Ya'akov, by Jacob ben Samuel Koppelman ben Bunem, of Brzesc (Kuyavia), Freiburg, 1584, and with a larger commentary by Gedeliah ben Solomon Lipschitz, Venice, 1618. The passages containing criticism of Christian belief (3:25-26) were expunged by the censor from later editions, while Gilbert Genebrard wrote a refutation of these passages with valuable notes. This refutation was published with his own remarks by the baptized Jew Claudius Mai, Paris, 1566. The manuscript copies of the book were also subject to intense censorship. Translations

The Ikkarim was translated into German by Dr. W. Schlesinger, rabbi of Sulzbach, and his brother, L. Schlesinger, wrote an introduction to the same, Frankfort-on-the-Main, 1844. There is an English translation of the book by Isaac Husik, published as a bilingual edition by the Jewish Publication Society in five volumes, 1946 (ASIN: B001EB9NWK). A French translation with critical edition of the third chapter and commentaries was published by Philippe Bobichon: Yosef Albo, Sefer ha-‘Iqqarim [« Livre des Principes »], III, 25 : Un chapitre de la controverse judéo-chétienne dans l’Espagne du XVe siècle (texte hébreu traduction, commentaires), Madrid, CSIC, 2015 online

References

External links
 Online edition of the book
 Scanned edition online
 Hebrew text and English translation of Sefer HaIkkarim 

Jewish philosophical and ethical texts
Hebrew-language religious books