In their quest for the why of an event, historians look at both the immediate and the long-term circumstances of that event. Not all causes are equally significant; we need to rank them in importance. Let us begin with a thought exercise. At this moment in your history, you are reading this textbook. Why? Perhaps you would say, “Because the instructor told me to, and it will be on the test.” Certainly that is a valid reason. But if you think a bit more deeply, you might also say, “I want to do well in my education so I can be successful.” And at an even deeper level, “Society tells me that education is necessary to realize my full potential, find fulfillment, and participate in the community.” Think of all the other things that caused you to be here in this moment. There are no wrong answers; just explore the levels of causation behind your reading right now. Now rank them in order of importance. Which causes had the most influence on you, and which were more remote? Your response might look something like a pyramid (Figure 1.10). The primary cause is the most immediate. It is the spark. The secondary cause is once removed. The tertiary cause offers the broader context. Figure 1.10 This causation chart answers the question, “Why are you reading?” on three levels. The primary level is the most immediate. (attribution: Copyright Rice University, OpenStax, under CC BY 4.0 license) To reach a true understanding of why you are reading your text, you needed to know yourself well, understand the connection between education and career, and assess how social factors, such as the value employers place on education, influence your decision-making. The more aspects of causation historians can find, the closer they can get to the true nature of the event. Let’s try another example, this one from history. Why did the United States enter World War II in 1941? In this case, the immediate cause was Japan’s attack on the U.S. naval base at Pearl Harbor in Hawaii, but hostilities had been brewing for some time. The president of the United States, Franklin D. Roosevelt, had been looking for ways to help the British fend off a potential German invasion, and Japan and the United States had long-standing issues over the use of power in the Pacific (Figure 1.11). Figure 1.11 This causation chart identifies and ranks the reasons for the entry of the United States into World War II. (attribution: Copyright Rice University, OpenStax, under CC BY 4.0 license) Here is one more example. In 1453, Mehmed II laid siege to the city of Constantinople. Why? Mehmed II was the leader of the Ottoman Empire, the sultan. He had been badly treated by his father, and when he ascended the throne, he felt he had something to prove. The Ottomans had tried several times to take Constantinople because it lay at the crossroads of many civilizations. Conquest had long been a reliable mechanism for bringing new people and wealth into the Ottoman Empire and for keeping its economy prosperous. All these factors played a role in the siege undertaken by Mehmed II. Can you order them by importance? This is the point where historians usually disagree, even about events for which most of the facts are clear. A historian who believes powerful leaders are the most influential factor driving events would rank Mehmed’s personal goals first (Figure 1.12). Base your ranking on the strongest arguments you can make. Figure 1.12 This causation chart ranks the reasons for Mehmed II’s 1453 Ottoman conquest of Constantinople. (attribution: Copyright Rice University, OpenStax, under CC BY 4.0 license) There can be more than three causes to any event, of course, and because human choice always plays a role, we sometimes cannot separate events on the big stage from the smallest of personal moments in history. The context of the Ottoman Empire’s continuous expansion set the scene in this example, and Mehmed II’s desire to prove his ability was the spark. Before moving on, try one more example on your own. Pick a moment in history with which you are familiar and follow the same process.