The author uses the word "immediacy" (line 39) most likely in order to express

Question 3: Why is that the intermingling of ideas is seen as a necessary condition for rapid advance of civilization? I understand that it's because the word "necessary" is in front of it, but that is just the mechanical way of looking at it. I don't really understand the logical validity behind it - it could also be that if there is an intermingling of ideas then there is rapid advanced civilization correct? Or is it that in questions like these we don't look at the actual truth of the statements and just go by assuming the statements given in the passage to be true? In question 4 - I did not understand why the last either/or sentence was not taken to be a sufficient and necessary statement. I saw that there has been a message board on this already, but I still didn't understand it properly. Can a more elaborate explanation with examples of what a valid either/or sufficient-necessary statement would be and what would not, be given? Because he did not consider the either/or statement of this question to be a valid one, I assumed that the either/or statement in question eight isn't a sufficient necessary statement as well, which turned out to be incorrect. Sorry for the long question, but would really appreciate an explanation! Thanks!