Economists are no better than weathermen at predicting anything.
Evolution - just do some research. The only side arguing against it hasn't been exactly reliable in terms of furthering our understanding of our World.
I think it's pretty well established that taxes during a recession is a bad idea...
The important thing is do your own research. If you want to use a fact in your argument, make sure it is accurate and not just propaganda. In my opinion, the way best to support your claim is to consider the counter-argument so you can refute it when it is presented.