This passage, too, is a reference to Catholicism. Transubstantiation is the conversion of bread and wine into the body and blood of Christ during the Eucharist, and consubstantiation is the Protestant belief that the bread and wine
coexist with the body and blood of Christ. In Catholicism, Holy Communion (the body and blood of Christ) is that unifying substance. The idea is that in consuming the body and blood of Christ, Catholics become one under Christ, which Hobbes argues is ridiculous. A substance cannot change into another substance through incantation, he argues, and multiple bodies cannot be made one through ingesting a shared substance.