 Swinburne has constructed a couple versions of an argument which purports to show why, if there is at least one divine being or Person, there must be exactly three, with the second and third being caused ultimately by the first. In other words, given that it is possible that there be a divine Person, it is metaphysically impossible that there be only one, and it is metaphysically necessary that there be exactly three. Most trinitarians have assumed that such an argument is neither possible nor desirable, as the Trinity can be known only by divine revelation. Against this, Swinburne says that “even if you regard the New Testament as an infallible source of doctrine, you cannot derive from it a doctrine of the Trinity”, because when it comes to passages about the Spirit,