For the past couple of centuries the Western World has tended to judge reality by what can be proved scientifically. Yet increasingly we have come to see that there are all sorts of realities that are not perceived by deductive reasoning, but are perceived intuitively. For example, you could read a learned treatise on the physical, chemical, psychological and sociological factors involved in falling in love, but never understand what falling in love is. But we all have an intuitive understanding that there is such a thing as falling in love. It’s one of those realities we grasp intuitively, not intellectually.
Faith is like that. Faith taps into that deep well of spiritual reality that lies, often hidden, within us all. Faith is the intuitive understanding that those spiritual realities are true and accessible.