<p>Comments:</p>
<p>Hmm... Well, for the introduction... </p>
<p>Well, the first sentence has no relevance at all to your thesis, and when you say that "the history of war is a testimony to that statement," you made it seem like you were going to talk about that. Then you give your thesis, so your introduction seems disjointed. How about, </p>
<p>"Changes are ubiquitous in the society that we live in. Most changes, however, are provoked by two things: necessity and force. Drastic events ignite change through force and necessity. This is clearly and ostensibly displayed in two examples from war: Truman's change from isolationism to involvement, and the changes in emotional state caused by the horrors of war.</p>
<p>You have to ask yourself: What is in this introduction that separates it from your previous one?</p>
<p>Your first body paragraph is good! I'd just like to see more commentary on how the necessity prompted change. You can elaborate by saying that if the U.S. had not been attacked, America would have remained isolationist, because nothing propelled it to change. After America had been attacked, however, it quickly realized that "not changing" (there's a word for it, I can't think of it right now), would have very possibly resulted in disaster. So it was the shock of danger that agitated change.</p>
<p>Your second paragraph doesn't really explain what motivates change, because in your example, people couldn't decide whether to change or not--you gave a mental condition. It would have been better to give an example where something forced people to make a conscious change. Do you see how a mental condition doesn't really fit in with what "motivates" change? The word "motivates" has a connotation of consciousness to it.</p>
<p>Your conclusion is fine for the most part. I'd say that you should change the last sentence, because it seems like you just threw a broad belief up in the air. Don't say something that you haven't proven in your conclusion. Many readers might disagree with your last sentence, and that can turn a good impression on your essay into a negative one. A better sentence is "Necessity and force agitate the change that we see every day." That connects more to your argument, and it even makes a nice connection to the introduction. This example is better because it wasn't just a random statement--it had meaning and it connected to the whole essay.</p>
<p>Other SAT words for motivate or cause are evoke, engender, prompt, provoke, elicit, precipitate, animate, inaugurate, and attribute.</p>