A quote. #2

"We can never understand a composition in its full concrete effectiveness for all possibilities of environment. We are aware only of an abstraction. For this abstraction the change or addition of factors may be indifferent. There is always a nemesis hanging over the equivalence, or consistency, of different things. As we enlarge self-evidence the abstraction shrinks, and our understanding penetrates towards the concrete fact. Thus, sooner or later, growth in knowledge leads to the evidence of antagonism involved in difference."

-Alfred North Whitehead (Modes of Thought p.60)