"So a trend predicated upon current behavior is "speculation upon speculation", but a belief (stated without supporting evidence) that current behavior will change the way you think it will is far more scientific and rational?"
Sure, it's possible that the birth rate of immigrants to Europe drops to the levels of the native European but what evidence do we have that this is happening. The article cites one study from the Netherlands which suggests there may be some indicators that this is happening but it's far from overwhelming. Furthermore, I quote the following from the Newsweek piece:
"For the number of Muslims to outnumber non-Muslims by midcentury, it would require either breeding on a scale rarely seen in history or for immigration to continue at a pace that's now politically unacceptable. More likely, new controls will slow Muslim immigration. "
Correct me if I am wrong, but how can something become "politically unacceptable" at the same time that a particular group is increasing its share of the European voice?
What's politically unacceptable is that Euro-bureaucrats will crackdown on immigration from Islamic countries. Fear is debilitating.