IN THE PREVIOUS APPENDIX, I made reference to the Tosafists’ discussion of what they call ‘association’. Because of the importance of this text to a key contention of this book, I present here a more detailed and technical analysis.

A talmudic regulation urged Jews to avoid business partnerships with pagans lest a dispute arise in which the non-Jewish partner would take an oath in the name of his god. The Jew would thus violate a biblical injunction that the Talmud understands to forbid causing someone to invoke the name of ‘another god’. What is the standing of this regulation in Christian Europe?

The Tosafists maintain that accepting an oath from Christians is permissible because they swear in the name of the saints, to whom they do not attribute divinity. It is true, Tosafot continues, that they mention ‘the name of Heaven’ (presumably God) along with the saints ‘and their intention is to something else [a better text reads ‘Jesus of Nazareth’], but this [i.e. ‘the name of Heaven’ without explicit mention of Jesus] is still not an idolatrous name. Also, their intention is to the Creator of heaven [and earth].’ This last sentence may mean either that in addition to Jesus they have in mind the Creator or, in a formulation more accurately reflecting Christian doctrine, that while they think of Jesus their ultimate intention is the true Creator. In either case, Tosafot maintains that Christians intend to worship the true God but cross a crucial line by incorporating a human being into their conception of the divine. The Tosafists even considered the possibility that one actually pronounces the name of a foreign deity by simply saying the word ‘God’ with Jesus in mind, and they take for granted that the explicit invocation of his name would run afoul of this prohibition.

This, however, is not quite the end of the text. The enigmatic continuation, which has produced a literature unto itself, says, ‘And even though they associate the name of Heaven with something else, we do not find that it is forbidden to cause someone else to associate, and the commandment not to cause a blind man to stumble [i.e. not to cause someone to sin] does not apply because Noahides [i.e. non-Jews] were not commanded regarding this [i.e. association, as an alternative version of the text says explicitly].’