"Unsupported by evidence" doesn't quite ring true, at least not in the case of historical Christianity. Throughout the gospels (eg., the raising of Lazarus from the dead in John 11), Jesus performed miracles, specifically in Lazarus case, 'so that they might believe.' Miracles were supposed to be clear evidence that he was who he claimed to be. The Apostles made well-reasoned arguments, & cited a plethora of eyewitness testimony, in order to persuade their listeners to believe. They never said, "Just take our word for it: faith is blind!" I'm not making a case for Christianity; I'm just saying that the definition of faith is too simplistic, or at least is not consistent with what many people 'of faith' think about the nature of faith.