Debbie: We argue a lot, yet what do we need to do to be convinced by it? What makes some arguments good, and others bad? How should we assess an argument, and whether or not to believe it?
Adam: Take a recent example. William Lane Craig offers something called a Kalam Cosmological argument, which runs like this:
- Everything that begins to exist has a cause.
- The universe began to exist
- The universe had a cause.
The argument is valid – that is, the conclusions follow from the premises. The question is whether the premises are true. Craig’s standard conception of what makes a good argument is whether or not the premises are more plausible than their negations.
Is that sufficient? Suppose that you do find each premise more plausible than it’s negation, but not by much: so you assign something like P=0.6 for each premise. Yet, given this the probability of the conclusion is only around 0.36, so you shouldn’t accept it. Continue reading “What makes a good argument?”