The topic of the VT debate was “Does God Probably Exist, or Not?”  I used a cumulative case approach for my arguments.  Below is my opening statement:

This evening we will be defending the proposition “God probably exists.”  We will present three different arguments for theism. To defend our case we will be using the prime principle of confirmation: Whenever we are considering two competing hypotheses, an observation counts as evidence in favor of the hypothesis under which the observation has the highest probability. This principle is sound under all interpretations of probability.  Each argument must be taken on its own grounds and one cannot arrive at “God” at the end of each argument.  The conjunction of arguments is what is needed to make a cumulative case for the existence of God.

The Likelihood Principle of Confirmation theory states as follows.  Let h₁ and h₂ be two be competing hypothesis (in this case the existence of X and ~X, with X being a first cause, fine-tuner, etc.).  According to the Likelihood Principle, an observation e counts as evidence in favor of hypothesis h₁ over h₂ if the observation is more probable under h₁ than h₂.  Thus, e counts in favor of h₁ over h₂ if P(e|h₁) > P(e|h₂), where P(e|h₁) and P(e|h₂) depict a conditional probability of e on h₁ and h₂, respectively.  The degree to which the evidence counts in favor of one hypothesis over another is proportional to the degree to which e is more probable under h₁ than h₂: particularly, it is proportional to P(e|h₁)/P(e|h₂) .  The Likelihood Principle seems to be sound under all interpretations of probability.  This form is concerned with epistemic probability.