Hasdai Crescas: Jewish Philosophy Unintentionally Including Christian Beliefs

One of the most tragic occurrences in Judaism’s long history is the frequent absorption of alien, often heathen and Christian notions.[1] This occurred not only amongst the uneducated masses; rabbis fell prey to this phenomenon as well, simply because they did not know Jewish history or understand the processes involved in the assimilation and rationalization of beliefs to correspond with a person’s perception of proper Jewish thinking. The story of Rabbi Hasdai Crescas and his impassioned battle against Christianity is a good example of this phenomenon.

In 1391, the Christian Spanish population rioted against their fellow Jewish citizens, killing many of them and destroying their long-established and flourishing communities. Many Jews rushed to convert to Christianity in order to save their lives. The hostilities continued for about one hundred years, on and off, until 1492, when the remaining Jews were viciously expelled from Spain or forced to convert.

The Jewish leadership reacted to the mass conversions after 1391 by attempting to convince their lost brethren to return to Judaism, pointing out what they considered to be illogical elements of Christian belief. One of the attempts was a short book written by Hasdai Crescas in 1398, The Refutation of the Christian Principles.[2]

Crescas had been greatly affected by the situation, his own son killed during the brutal riots. His book aimed to prove that Christian beliefs were mistaken, and based the argument on two logical premises: (1) religion must conform to the truth as we know it, be rational and not teach irrational beliefs, and (2) each of its teachings must recognize that God can only do good.


Hasdai Crescas

Rabbi Hasdai Crescas was born around 1340 and died about 1410. He was Chief Rabbi of Saragossa, Spain, and was involved as a diplomat in the royal court of Aragon, with the title Member of the Royal Household. As a young man, he was a merchant and wrote poetry. He was a student of the famous Rabbi Nissim Gerondi and the teacher of the well-known Rabbi Joseph Albo. He is remembered primarily because of his philosophical treatise Light of the Lord in which he attacked Aristotelian rationalism and the views of his great predecessor Maimonides. He respected the brilliance of both philosophers but rejected their writings because Jewish intellectuals used them to justify their desertion of Judaism.


Crescas’s Philosophy

Among other things, Crescas, in contrast to Maimonides, believed that God knows everything about every person, that God watches over everyone and communicates through prophecy and that God revealed the Torah because of love of humankind. Crescas, according to some scholars, may have also believed in the transmigration of souls, the idea that souls are reincarnated in future humans and animals. As we will see, he also accepted many Christian notions such as original sin, thinking that they were original Jewish thoughts.


The Basic Teachings of Christianity According to Crescas

Crescas identified ten basic Christian beliefs:

  1. The original sin of Adam was passed on to his descendants.
  2. This sin was removed with the death of Jesus.
  3. A trinity exists: God the father, the Son, and the Holy Ghost.
  4. The Son took on flesh and became human in Mary’s womb.
  5. Mary remained a virgin before, during and after Jesus’ birth.
  6. When the priest utters certain words, he transforms wafers and wine into the body and blood of Jesus.
  7. He who has not been baptized has no share in the world to come.
  8. The messiah has come.
  9. Christians were given a new testament and do not need to observe all the laws in the Hebrew Bible.
  10. Demons exist. The demons were originally good angels, but they sinned because of jealousy and pride in the very first instant of their existence. They were punished by being deprived of free will, and they became wicked.


Inconsistencies in Crescas’s Writings

Crescas’s Refutation is a polemical book designed, as we said, to refute Christian beliefs, while his Light of the Lord is a philosophical work in which he details his personal beliefs. There are some contradictions between the two works – apparently, but by no means certainly, because the rabbi felt that it was expedient to say what he did not believe in order to accomplish his important purpose of saving Jews from error.[3]

Thus, for example, although Crescas believed that life after death is only achieved by the observance of mitzvot, the biblical commandments, he insists in his Refutation that “he who worships God can achieve [life in the world to come] naturally by means of his speculative life which causes pleasure to his soul.” He probably took this position in the Refutation because it was consistent with his basic statement about the falsity of the Christian beliefs: thinking is important; a religion must teach that which is rational.

Similarly, while he rejects the belief in original sin in his Refutation because it is illogical to suppose that innocent and righteous descendants should be punished for the misdeeds of their ancestors, he accepts this clearly Christian idea in his Light of the Lord.[4] He states that Jews were absolved of the original sin when they were circumcised. This idea about being absolved was also a Christian teaching – that prior to the appearance of Jesus circumcision saved the Jews from the impact and punishment of the original sin.

He states in his Light of the Lord, contrary to logic, that just as good descendants can benefit from the past good deeds of ancestors, the opposite is also true: the evil descendants of the patriarch Isaac are rewarded because of the meritorious act of Isaac when he agreed to be sacrificed in Genesis 22.[5]

Be this as it may, Crescas was consistent in his view regarding demons. Many of the Jewish masses before and after him were convinced that demons plotted and performed pernicious acts in the dark corners all around them, and in both his Refutation and his Light Crescas states that he also believes in them. He even cites what he considers to be biblical proof for the existence of demons.


Demons in the Bible

In order to back up his claim, Crescas draws on sources from the Bible. For example, Deuteronomy 32:17 states “they [the Israelites] sacrificed to demons that were no gods.” Similarly, Leviticus 17:7 mandates that the Israelites stop these sacrifices, “they shall no more slay their sacrifices to satyrs.”

A host of talmudic rabbis rejected the notion that demons exist, but there were also many, like Crescas, who accepted the superstitious notion.[6]


Maimonides’ Interpretations of the Biblical Verses

While Crescas believed that scriptural verses affirmed the existence of demons, Maimonides disagreed. Maimonides[7] understood that the Bible was stating that the Israelites had sunk so low that they worshipped imaginary things that did not exist. It is as if the verses are saying: “they sacrificed to what they considered to be demons, that in truth were not gods or demons” and “they shall no more slay their sacrifices to imaginary demons and satyrs.”


What, Then, Was Crescas Refuting About the Christian View of Demons?

Curiously, Crescas focuses his disputation upon the single detail, “the Christian belief that in the first instant of [their] existence, they [the demons] sinned with jealousy and maliciousness.” He presents several arguments to demonstrate that it is impossible for the angels to be both a good divine creation and “sinners” at the very same “instant of creation.”

He does not mention that not all Christians hold the view that the “sin” occurred in “the first instant of existence,” nor does he state his own view about when the demons came into existence. However, it is clear that he believed that God did not create evil, that demons were good when they were created and subsequently, and that God created demons to test, reward, and punish human beings.



The story of Rabbi Hasdai Crescas and his book refuting what he considered to be Christianity’s basic principles highlights the tragedy that many Jews, including prominent well-educated Jewish leaders, teachers and rabbis, absorbed non-Jewish ideas, a phenomenon that tragically continues today. At the very moment when the religious life of many Jews was being quashed, when many felt they had to convert to Christianity to save their lives and their families, when Jewish leaders felt obliged to issue refutations of Christianity to save them from such a mistake, Jewish leaders, like Crescas, wrote pamphlets and books refuting Christianity that unconsciously labeled basic Christian beliefs as Jewish, including faith in an original sin and the idea that demons control their lives.

The Jews of the fourteenth century, as well as many before and after, as discussed previously, believed in the existence of malicious devils. This was a relic of ancient heathen fears and the basis of many stories in the Christian Gospels where Jesus is portrayed as combating and defeating them. So engrained and absolute had this non-Jewish teaching become in the Jewish mind that Jewish leadership could only differentiate the Jewish thinking from the Christian by focusing on a rather minor arcane point in the view of just some of the Christian thinkers as to when the demons were created, and argue that the time-frame was wrong.

Undoubtedly, Rabbi Hasdai Crescas had good cause for writing his The Refutation of the Christian Principles. Many Jews were murdered by Christian riots, including his only son. Jewish communities were destroyed and a host of Jews converted to Christianity to avoid future persecutions. As a leader of Spanish Jewry, he felt obliged to do what he could to return the converts to their faith.

His Refutation was based on a premise that religion can only teach what is rational and that God can only create what is good. Yet, curiously, his misguided opinion about demons was so firmly embedded in his mind that, like many other Jews, he was unable to see that his thinking about these creatures was not rational, and that, contrary to his attempt to rationalize his conviction, demons do not serve good divine purposes.

Crescas’s positions regarding demons and original sin are just two of many examples demonstrating that many – in fact, nearly all – Jews absorbed pagan and Christian notions that are contrary to rational Judaism, Maimonides being a remarkable exception.


[1] For example, many people do not realize that when they say “gosh almighty” they are referring to the Christian Holy Ghost and when they say “bloody” they are referring to the blood of Jesus.

[2] An English translation with commentary was composed by Daniel J. Lasker of Ben-Gurion University in 1992.

[3] He was not the only rabbi to do so. Some years earlier, Nachmanides was involved in a dispute sponsored by the Spanish king in Barcelona in 1263. Nachmanides had to support the views of Judaism against those presented by Christian clergy and Jewish apostates. During the confrontation, Nachmanides took the position that the tales told in the rabbinical Midrashim were not true in order to protect himself from the position taken by his opponents who believed that some Midrashim supported Christianity. Actually, Nachmanides believed that the midrashic stories were true history.

[4] Some other rabbis in the Babylonian Talmud, Avodah Zarah 22b, Shabbat 145b–146a and Yevamot 103b also accepted this notion.

[5] Isaac’s agreement to be sacrificed was assumed by other thinkers as well even though Genesis itself seems to imply that Isaac had no idea what his father Abraham planned to do to him and even repeatedly asked his father what was happening.

[6] These conflicting approaches to the subject are discussed in E. E. Urbach’s The Sages, 161–165, as well as some of the other chapters in this book.

[7] Guide of the Perplexed 1:7, 3:22 and 46.