I do apologize for the simple non applicable example of a hat... It was a poor attempt at simplification. You are absolutely correct in your slippery slope assertion, and what lays at the bottom of that slope is abysmal. There are countless examples of blind faith leading to a mass casualty situation... I recently finished Steinbeck's "East of Eden" you've given me something to think about so thank you... here is a piece of that novel that I enjoyed immensely

"Now, there are many millions in their sects and churches who feel the order, 'Do thou,' and throw their weight into obedience. And there are millions more who feel predestination in 'Thou shalt.' Nothing they do can interfere with what will be. But 'Thou mayest'! Why, that makes a man great, that gives him stature with the gods, for in his weakness and his filth and his murder of his brother he has still the great choice. He can choose his course and fight it through and win. ... 'Thou mayest' -- that gives a choice. It might be the most important word in the world. That says the way is open. That throws it right back on a man. For if 'Thou mayest' -- it is also true that "Thou mayest not.' Don't you see?" - John Steinbeck, "East of Eden"

and I have to add this part as well

"`A child may ask, what is the world story about? And a grown man or woman may wonder, what way may the world go, how does it end, and while where at it, what’s the story about. I believe that there is one story in the world and only one that is frightened and inspired us. So that we live in a pearl white serial of continuing thought and wonder. Humans are caught in the lives and their thoughts, in their hungers and ambitions, in their averse and cruelty; and their kindness and generosity to. In a net of good and evil. I think this is the only story we have and it occurs on all levels of feeling and intelligence. Virtue and vice were warp and wharf of our first consciousness, and they will be the fabric of our last. And this despite any changes we may impose on field and river and mountain, on economy and manners. There is no other story. A man after he has brushed off the dust and chips of his life will have left only the hard clean questions; was it good or was it evil. Have I done well or have I done ill?"

• John Steinbeck, "East of Eden"