If I explain to a student that the electron configuration of the copper atom is such and such, I am making a statement which I hold to be true. I hold be true on faith because I have not performed the chemical analysis that revealed the element's structure nor have I made the observations that lead to the structural explanation. A disposition to assent is not the assent itself. A student is disposed to accept the word of his teacher. A teacher is careful to substantiate his assertions, though in many cases substantiation may elude him.
Substantiation amounts to demonstration.
Demonstrative knowledge we normally call scientific knowledge. Some, but not all of our beliefs, are based on demonstration. When certitude which depends on demonstration is not available, we get opinion. The strength of our opinion will determine action or inaction. The conviction that intervention by the Federal Reserve will create monetary stability may lead a president to take action.