Marc B. Shapiro writes:
Throughout Jewish literature one can find any number of explanations as to how the notion of the Trinity is in direct opposition to Jewish teachings, since Judaism demands a simple, unified God. There is no doubt that for much of our history this was the standard view. However, once the doctrine of the sefirot arises on the scene, matters change. Many of the arguments put forth by kabbalists to explain why the belief in the sefirot does not detract from God’s essential unity could also be used to justify the Trinity, a fact recognized by the opponents of the sefirotic doctrine. Since the doctrine of the sefirot has become part and parcel of Judaism, we must now acknowledge that Judaism does not require a simple Maimonidean-like, divine unity.
In fact, without any reference to the sefirot, R. Judah Aryeh Modena was able to conclude that one could indeed justify the notion of the Trinity so that it did not stand in opposition to basic Jewish beliefs about God’s unity. As Modena points out in his anti-Christian polemic, Magen va-Herev, the real Jewish objection to the Christian godhead is not found in any notion of a Triune God, but in the Christian doctrine of the Incarnation.35 The idea that God assumed human form, i.e., that a human is also God, is regarded by us as way over the line. This is not only because it deifies a human, but also because there is a great difference between a spiritual God divided into different “parts,” and an actual physical division in God. The latter is certainly in violation of God’s unity even according to the most extreme sefirotic formulations. (It would not, however, appear to be in violation of R. Moses Taku’s understanding of God, since he posits that God can assume form in this world at the same time that He is in the heavens. For Taku, Christianity’s heresy would thus be seen only in their worship of a human, which is avodah zarah.)
From the Trinity, let’s turn to Virgin Birth, another phenomenon which everyone knows is not a Jewish concept, or is it? If by Virgin Birth one means conception through the agency of God, then there is no such concept in Judaism. Yet if by Virgin Birth we also include conception without the presence of human sperm, then as we shall soon see, this indeed accepted by some scholars. (I stress human sperm, so that we can exclude the legend of Ben Sira’s conception, which occurred by means of a bathtub, not to mention all of the responsa dealing with artificial insemination.)
Pre-modern man believed in all sorts of strange things, one of which was the concept of the incubus and the succubus, which was found in many cultures. The idea was that male and female demons would have sex with humans while they slept. Among the outstanding Christian figures who believed the notion possible include Augustine and Aquinas.36 This was an especially good way to explain an unwanted pregnancy: just blame it on the demon. While the classic example of the incubus is when a male demon comes upon a sleeping woman, there were times when this happened while both parties were awake, and we will soon see such a case in Jewish history. Lest one think that this is only a pre-modern superstition, what about all those people who claim to have had sexual relations with aliens who abducted them?
