Book Review: Was Jesus God? (2008) by Richard Swinburne.
Former University of Oxford professor Richard Swinburne answers his own question: "probably".
Swinburne isn't hedging his bets or laying odds for Vegas. He's revealing his philosophical methodology. Was Jesus God? represents Swinburne's extensive use of Bayes' Theorem, although he never mentions it by name.
Swinburne starts with his conclusion from his "prequel", Is There a God? (reviewed here on July 10, 2009) that God probably exists (p. 1), which he briefly revisits in Chapter 1. From there, he concludes that it's probable that God is a Trinity (Chapter 2); that God would become a human to identify with humanity's suffering and to atone for their sin (Chapters 3 and 4); that He would give us teaching for living (Chapters 5 and 11); and He would found a church to propagate it (Chapter 10), among other things.
In particular, Swinburne's defense of Trinitarian doctrine (as enunciated in the Nicene Creed) is something to behold. Swinburne writes: "The love of the Father for the Son must include a wish to cooperate with the Son in further total sharing with an equal, and hence the need for a third member of the Trinity...the Holy Spirit, whom they will love and and by whom they will be loved. A universe in which there was only sharing and not cooperation in further sharing would have been a deficient universe; it would have lacked a certain kind of goodness. The Father and the Son would have been less than perfectly good unless they sought to spread their mutual love of cooperating in further sharing with an equal." (p. 29.)
Swinburne draws the line at three. "So the perfect goodness of the Father would be satisfied by his bridging about only two further divine persons. He does not have to bring about a fourth divine person in order to fulfil his divine nature. But then any fourth divine person would not exist necessarily, even in the sense of metaphysical necessity. His existence would not be a necessary consequence of the existence of an ontologically necessary being and hence he would not be divine. So there cannot be a a fourth divine person. There must be and can only be three divine persons." (p. 33.)In so defending the Trinitarian formulation, using Bayes' Theorem, Swinburne somewhat undercuts his prior use of Ockham's razor for God's existence (i.e. the simplest explanation holds). (See my July 10, 2009, post about Swinburne's Is There a God?). No matter how one articulates it, the Trinitarian doctrine is not a model of simplicity. Swinburne seems to concede this apparent inconsistency (calling the Trinity "a very sophisticated" concept [p. 38]), but he labors to reconcile it by claiming that the Trinity is actually a simple construct because it "depends on two very simple moral intuitions: that perfect love requires total sharing with an equal and requires cooperating in spreading that love further, so that anyone you love has someone else to love and be loved by." (p. 38.) Here we see fissures erupting where Swinburne's two primary philosophical methodologies abut each other; they simply don't meld seemlessly in this context.
In any event, this book represents an elegant extrapolation from Swinburne's premise that God "probably exists". He traces probabilities from God's existence through the primary tenets of Christian doctrine, and in so doing produces an innovative approach for Christian philosophy of religion worthy of study and discussion.