Is It Crazy to Believe in something rather than to Know Something?

I was completing a research project on whether certain religious beliefs are psychological a strong holds on particular groups of people throughout the world. So I thought this would be an excellent question to post and get the POV from others.

Lets go back to the 12 century and look at the etymology of the word believe. Believe, in the old Germanic langue/language was defined as "become limited to mental acceptance of something as true..." Now you can go further back to its Latin/Greek roots and it means "to give away the lie.." but for know let us go the 12th century meaning, "become limited to mental acceptance of something as true..."

- Believe or Belief
(Be-lie-ve / be•lie•f)

To believe is to become or to make manifest a thought into a reality or physical proof. If a person thinks something but that thought is not made into physical evidence or proof, then that thought is a LIE (be•LIE•f) and is not true. It is not true because there is not physical proof to substantiate its existence.

The layman definition of belief is an UNVERIFIABLE THOUGHT. So If a person BELIEVE in a thing that CAN NOT be verified with physical proof or evidence, and base their existence on that thing which cannot be proven, according to the medical society, that person has a Psychological impediment or is mentally sick.

- Psychological impediment

[The affects your of mind caused by your feeling or thoughts; something that makes it more difficult for someone to do something or more difficult for something to happen; psychological problem that affects how well someone can do something] [Understanding Psychology 8th Edition]

So now what do you think? Is It Crazy to Believe in something...?