Like others here I don't think you want Bayesian logic, it sounds like what you are trying to do is similar to predicting the weather based on today's readings.

I would suggest that what you want is probably fuzzy logic. As it happens June's Perl Journal has an article on that topic (and its only $12 for a year, subscribe now :-) ). It mentions AI::FuzzyInference as a good CPAN module to use.

I would also suggest looking at Peceptrons and neural nets.

There have been all sorts of books on complexity and predicting dynamic systems. For example I found the book "The Recursive Universe: Cosmic Complexity and the Limits of Scientific Knowledge" by William Poundstone really good