Apologists like Peter Kreeft and William Lane Craig always seem to end up arguing for theism using some kind of cumulative case argument. Basically, they want to admit that many of the arguments for theism taken in isolation are fairly weak (or at least inconclusive), but they think that as a complete package it’s very convincing. The package would include things like C.S. Lewis’s famous (and famously bad) argument from desire, the moral argument, first cause argument, consciousness, free will, logic and mathematics, and so on.
It’s always seemed to me that the most they could ever get with this kind of thing is a cumulative case against materialism. That is, there is just too much stuff that materialism can’t explain and therefore it must be false. But as far as I can see there’s no way that you can get anything like a Christian world view until you look at those scriptures (and at church history etc).
That’s rather funny. An argument on behalf of cumulative evidence works in the case of rigorously collected data, but it does not work in the case of different philosophical arguments.
In the case of scientific data, any given data point is itself extremely weak evidence for a given proposition. It is only in the accumulation of data that propositions are verified or demonstrated false. But that data has to be good data: as the adage goes, the plural of anecdote isn’t data. It’s just more anecdote. The fact that you think you’ve seen a ghost and you’ve heard of fifty people on TV who’ve done the same is not good data in favor of the existence of ghosts.
OTOH a statistically well designed, double-blind, placebo-controlled study of a proposed cancer drug is better if there are 1000 data points rather than 100.
Things are a bit more squirrelly in the case of meta-analyses, which analyze data from several scientific studies. The problem with meta-analyses is that the analyses which are themselves reviewed for the meta-analysis must themselves be well designed, and relevantly similar. Otherwise the meta-analysis is sort of an exercise in garbage-in, garbage-out.
This line doesn’t work at all with philosophical arguments, however. Philosophical arguments aren’t scientific data: they can’t be accumulated towards some goal. A bad or weak argument is just that: bad or weak. The plural of bad or weak arguments isn’t a good argument, it’s a lot of crap. Think of it this way: given time, I’m sure I can come up with an unbounded number of bad or weak arguments in favor of any proposition at all. The fact that I can come up with a hundred doesn’t make that proposition any more credible than the fact that I can come up with ten. So if these folks are making this kind of apologistic argument in favor of God, all they’re doing is special pleading.