At one end, we have Counting Faith, which is "Belief with inductive evidence". This isn't really "faith" in the conventional sense- it is simply the belief that since some event X has always occurred, event X will continue to occur. Such a belief is flawed logic, but our brains are understandably wired to accept it instinctively- we don't need to understand orbital mechanics to believe that the Sun will rise tomorrow. But without understanding that- we don't know that it is really true. Just because "it's always done that" doesn't mean that it will continue to do so. Counting Faith is an invitation to examination and exploration.
Moving up the spectrum, we have Minor Faith, or "Belief with unreliable evidence". That is to say, there is some evidence, but it's certainly not a clincher, or it's incomplete, or misleading. For example, last Sunday, I believed that the Steelers would beat the Raiders (the Raiders are a horrible team, of course the Steelers should win!). I did not have any real solid evidence- both their records were equally bad, but the Steelers did win a Superbowl a year back- which isn't really good evidence at all. As it turns out, I was shown wrong (horribly horribly wrong!).
Next in line, there is Faith in the more conventional sense- "Belief in the absence of evidence". Either there is no concrete evidence, or the evidence is self-supporting ("The Bible is true because the Bible says that it's true!"). This starts getting us into the realm of the unfalsifiable- a dangerous realm to be in (and a short hop to Major Faith which we'll get to in a moment). Once you cross this line, you've moved into an intellectual vacuum- because it is very difficult to sway your faith (most religions indoctrinate their members to view any counter-evidence as the work of some evil force). Since you believe with no positive evidence, someone actually interested in facts must present negative evidence to sway you- they must disprove something- which is difficult (often impossible) to do. And even if someone does present meaningful counter-evidence, most religious believers tend to take the step to the next level of faith.
Major Faith or Serious Faith (or Terminal Faith (as in the death of thought)) is "Belief in the face of reliable counter-evidence". Serious faith is the mental illness that plagues Creationists. If plain Faith is an intellectual vacuum this is an intellectual repellant- the dark energy of rational thought. Evidence may be misinterpreted, dismissed, ignored because it doesn't agree with your pre-conceived notions- with your beliefs. This is the realm of true insanity, and once this level of faith has been achieved, there is no longer any absolute true or false- only things declared by fiat. True relativism.
Counting Faith and Minor Faith are useful shortcuts for day to day life. Most importantly, they are not divorced from the real world and can be shown false. If the Sun did not rise one day, I hardly think anyone would maintain that it had risen, but we are just to faithless to see it. Scientists would scramble to rebuild our understanding of the universe to incorporate this sudden change in the Earth's rotation. Like all good ideas, Counting and Minor Faith can be rejected.
In my coming essay on the subject of Faith, I won't spend any time on those, instead focussing on the true dangers- Faith and Major Faith. The other major task is to demonstrate that religion falls clearly on the side of Faith at best- not Minor Faith (poor evidence). At its worst, religion is in the realm of Major Faith. In any reasonable society, both would be considered problematic, and Major Faith would be grounds for medical professionals to take a hand.