LSAT逻辑推理例题分析：循环论证法
Free public education is the best form of education there is. Therefore， we must fight to ensure its continued existence; that is， we must be ready to defend the principle of equality of educational opportunity. Because this principle is we worth defending， it is clear that free public education is better than any other form of education.
Which one of the following illustrates the same weak reasoning as found in the passage？
（A） I love music， and that‘s why I listen to it constantly. I have my stereo or radio on every waking minute. Since I play music all the time， I must really love it.
（B） Books are my most valuable possessions. My books are like my friends—each pleases me in different ways. Just as I would give up everything to save my friends， so too with my books.
（C） I would much rather be poor and respected than be rich and despised. To have the respect of others is far more valuable than to have millions of dollars.
（D） I have never been betrayed by any of my friends. They have been true to me through good times and bad. Therefore I will never betray any of my friends.
（E） Because every plant I have ever seen has green leaves， I have concluded that all plants must have green leaves. This looks like a plant but it does not have green leaves， so it cannot be a plant.
答案：B
循环论证，就是需要用结论来证明论据和论点。换言之，前提和结论互为前提。
