In general, the institutions of society become more complex and centralized over time. The government comes to have more power over the society and things like religion become more organized and stronger. These changes tend to happen together (as seen in the Table 14.1). The changes in institutions also tend to make it easier for the agents of conquest to occur.
As society becomes more centralized, it becomes easier and more necessary to have things like writing and technology. Writing is needed for a bureaucratic state and a large population makes technological innovation more likely. Diamond says that this process does not always occur in exactly the same way (some plaes don't get writing, others don't get technology) but they do occur in this general way and they do give their societies advantages over the less centralized ones.
The institutions of society differ over time in reference with the size and complexity of that society. A small, nomadic band of primitive hunter-gatherers would have an egalitarian society where all members are equal and all have an equal say. As this band becomes larger, more people join it, until it becomes a tribe, not everyone can have an equal say. As a society becomes larger, there needs to be a leader that has the people’s best interests at heart. A small society might merely want to survive in seclusion from others, but a large civilization wants to expand their territory. When a society wonders about its existence, a centralized religion to come about is natural. A society then becomes a theocracy, and the leaders can use the religion as a tool to control the population and force other people to comply with them, like the European conquerors. Conquering other nations is an activity that Europeans loved to do. Of course, to do this, sophisticated weaponry was required. Steel weaponry and harquebuses were used to conquer new lands, not defend their home. However, all of these weapons pale in comparison to the destructive power of germs. A civilization needs to be fed, so livestock and meat need to be kept in a convenient place. However, the diseases that these animals harbor are deadly. But after hundreds of years of exposure, Europeans were immune. But these germs were still harmful to any new victims that were never exposed to them before.
Society needs sustenance and leadership. Innate diseases in animals are exposed to the population that eats them, and they grow immunity. The leader of a group wants do defend his own people and conquer new lands, which leads to the creation of weapons. The combination of disease and weapons led to the destruction of any civilizations that came into conflict with the European invaders.