We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.On the one hand this statement reflects the Enlightenment thinking of the authors such as Thomas Jefferson. The notion of certain things being true because they were "self-evident" was celebrated and claimed.
[Aside: A classic case was Euclid's axioms of geometry, which turned out to be actually assumptions that are not universally valid.]
On the other hand, the statement reflects the presuppositions of a Biblical world view and the Doctrine of Creation. The idea that "all men are created equal" goes against most world views that have been dominant throughout history and even today in some cultures and religions. The idea of equality and human rights is not "self-evident" or "discovered" but is actually a profound truth that was revealed to the author of Genesis by the Creator God.
This point was nicely made by Dave Pitt, in a recent talk at church.