In Chapter 15 of Guns, Germs, and Steel, Jared Diamond discusses the people of Australia and New Guinea. He uses the history of these people to bolster his claim that environmental factors shape societies. He says that the people of this area were “backward” because of their environment, not because they or their culture were in any way inferior.
Diamond says that the people of New Guinea and Australia had many disadvantages. For example, on p. 303 he tells us that Australia’s soil was the least fertile of any of the continents. As another example, he tells us on p. 304 that farming can only take place in New Guinea in places that are at least 4,000 feet above sea level. Later, we are told that neither Australia nor New Guinea had any domesticable mammals (p. 308) and that Australia had very few domesticable plants (p. 309). He concludes the chapter by saying that large-scale agriculture in this region was only possible when Europeans came, bringing everything they needed to create agriculture, including foreign plants and animals.
Chapter 15, then, supports Diamond’s overall argument in this book because it shows that New Guinea and Australia were “backwards” because of geography, not because there was something wrong with the people of this region. Diamond argues that geographical luck determined which regions became rich and powerful and which did not. By showing in Chapter 15 that New Guinea and Australia had bad geographical luck, he supports his main argument in the book as a whole.