Most people think astrology is bunk science, but they can make predictions and do experiments.
Throughout history physics has had experiments whose results were incompatible with current models, which eventually lead to new theories (relativity, etc) but how do you know when contradicting information disproves your theory or will expand it.
Definition 2 is a flawed definition, perhaps some parts of astrology are wrong, but some parts of physics are wrong, we just need more time to work out the bugs in astrology -- more experiments need to be made.
I think when your model consistently gives results indiscernable from random noise in its strongest application (cf. blog.okcupid.com), you can safely conclude that it's of no more value than a model selected at random from all possible models of similar complexity.
