Why trust a theory? Some further remarks (part 1)
  I expand on some ideas from my recent review "String theory to the rescue," I discuss my use of Bayesian reasoning. I argue that it can be useful but that it is very far from the central point of the discussion. I then review my own personal history with the multiverse. Finally I respond to some of the criticisms of Ellis and Silk, which initiated this interesting discussion. 
Joseph Polchinski
hep-th gr-qc physics.hist-ph