Chapter 11 & Chapter 12

In these two chapters, the author is basically talking about the need for concentrations and some myths about diversity as she titled. Combine these two together; the idea is population is a huge fact for the economic growth and city diversity. As she mentioned in the beginning of the chapter 11, "The district must have sufficiently dense concentration of people, for whatever purpose they may be there." By saying this, the author means a well planed city must have a well planed population of people in different areas. And people make diversity; people make economic function in the right track. In her point, if an insufficiently dense concentration of people happens, it will make a failure city plan. As Jacobs did in every other chapter, she also gave readers numbers of examples of both successful and unsuccessful plan for concentration of people and mixture diversity in different US cities. “The other factors that influence how much diversity is generated, and where, will have nothing much to influence if enough people are not there”(p205) And it is also one of the most important factor in city planning. By giving both the definitions of High densities and overcrowding, the author wants the readers to know that in real life high densities have nothing to do with overcrowding. She also showed us how to differentiate the two situations and how they can be bad and good in certain places and time. And in Chapter 13, the author asks problems about diversity and gives proofs to answer whether the question is right or wrong. Such as in page 229, at the button part, “Is it true that diversity causes traffic congestion? Traffic congestion is caused by vehicles, not by people in themselves.” So, Jacobs keep discussing about all different questions for diversity as the chapter goes.