We all believe in a lot of things which cannot be scientifically tested in a mass spectrometer or particle accelerator.
The Declaration of Independence asserts that all humans are created equal and are endowed with natural rights which supercede any king, secular law, or social convention. The French Universal Declaration of Human Rights makes similar claims.
There is no laboratory or experimental evidence to support that belief.
It is a social construct rooted in the philosophical belief in natural law.
Soren Kierkegaard said that most religious belief is fake and inauthentic. In 19th century Denmark, he felt most people claimed and demostrated belief simply by attending Church once a week and listening to the pastor. Kierkegaard maintained that true belief was far more difficult and complex than that.
"Believe in?"
We all?
I guess about some things; I speculate about some things; I hypothesize about some things. I do not hide the fact that I am guessing, speculating, or hypothesizing...by calling it "belief."
So, respectfully as possible, Cypress...not all of us do.