Neither statement can be faulted on the grounds that it is inaccurate; at the same time, however, neither is sufficient as an explanation of the event being considered. The next question is obvious: Why did you oversleep, or why did relations between one state and the Federal government reach the point where differences had to be settled by War? In other words, we have to go beyond the proximate cause and probe further and further. But as we dig more deeply into the problem, the answer becomes more difficult and complex. In the end, you might argue that the ultimate cause of your being late was the fact that you were born, but obviously this goes too far back to be meaningful. That you were born is of course a necessary factor, but it is not a sufficient factor; it does not really tell enough to explain your behavior today. Similarly you could trace the cause of the Civil War back to the discovery of America, but again, that is a necessary but not a sufficient cause. The point at which causes are both necessary and sufficient is not self-evident. Therefore historians may again disagree about where to begin the analysis. By now students should see that the well-used phrase "let the facts speak for themselves" has no real meaning.