Faith is always "believing in the unseen," that's basically what it is --whether it be something induced (like cause and effect) or something guessed at. Faith is always without proof, but never without evidence, with only two exceptions, the two things for which there cannot be evidence: "God", and "an objective reality".
"Faith is always "believing in the unseen," that's basically what it is "
In my opinion, I think you are too liberal with your use of "always". "Faith" comes in many shapes and sizes. Kierkegaard called faith "passion for inwardness".
"(like cause and effect)"
Cause and effect is demonstrable, you can see it in action. Ever play a game of marbles?
"Faith is always without proof, but never without evidence"
As I have pointed out before, to someone else, evidence is proof.
"the two things for which there cannot be evidence: "God", and "an objective reality"
There is plenty of evidence that there is an objective reality. Besides "objectivity" is simply a classification of the intersubjective reality that manifest itself before us. No matter what the true nature of reality is an "objectivity reality" will always be evident to us.
-----
I, myself, don't consider a belief that is based on a prudent rationalization from empirical evidence a matter of faith, that is a matter of reason. Also, empirical evidence does not always mean that it can be seen, but only that there is real hard evidence that it exist.