Blind faith isn't believing in something that one cannot see; but believing in something with knowing the alternatives.
Believing, for example, in God, is not completely blind in and of itself. BUT believing in the things one hears about God without considering the alternatives is. Take, for example, the issue of pre-destination. Many people will accept predestination as a fact of God without considering the other options, or even worse, they may have a face value knowledge of the alternatives. When a person believe in something and has only surface knowledge of the alternatives not only do they still have blind faith... but worse, they will think themselves as knowledgeable of the subject at hand. This can cause a person ridden in blind faith to also become stubborn and arrogant when it comes to the alternatives.
Faith isn't always blind though, like most people would like to believe that it is. Faith is hope in something, whether seen or not. Everyone puts their faith, or trust, in something. Such things may include money, self, culture, tradition, religion, happiness, democracy, and even education. Belief in these things alone is not solely bad or good, but believing in them without knowing the alternatives for belief is blind.
People may say that the religious realm is the only place where faith may be blind. This is not so. Take for an example an individual who believe completely in the power of money to bring themselves happiness. This faith is blind if the individual has also not considered or explored other areas that could possibly make them happy - but instead puts their faith solely in monetary value.
Thus, everyone possesses faith. Faith IS NOT a bad thing - nor is it always blind. Faith in something unseen isn't blind, it is merely the nature of faith. Blund faith is believing in something or a concept of something with the full knowledge of alternative ways of thinking about the subject.