Which source is used first and foremost to derive Islamic Knowledge?

The UK Science Council expanded the previously narrowed perimeters, defining science as denoting not only the natural or experimental branches of knowledge, but also denoting the humanities and social sciences as well. They said: 

“Science is the pursuit and application of knowledge and understanding of the natural and social world following a systematic methodology based on evidence.” [1]

Furthermore, in a 2009 article in the Guardian, A C Grayling commented on the definition saying: “Because ‘science’ denotes such a very wide range of activities a definition of it needs to be general; it certainly needs to cover investigation of the social as well as natural worlds; it needs the words ‘systematic’ and ‘evidence’; and it needs to be simple and short. The definition succeeds in all these respects admirably, and I applaud it therefore.” [2]

1. Science Council. (n.d.). Our definition of science. Retrieved May 6, 2017, from http://sciencecouncil.org/abou...

2.  Grayling, A. C. (2009, March 4). What is this thing we call science? Here's one definition ... The Guardian. Retrieved March 3, 2017, from https://www.theguardian.com/sc...