argument47 -anan

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Argument47  第16篇 让砖头来得更猛烈些吧！
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作者：寄托家园作文版普通用户     共用时间：20分1秒     235 words
从2007年3月11日11时9分到2007年3月11日11时20分
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Scientists studying historical weather patterns have discovered that in the mid-sixth century, Earth suddenly became significantly cooler. Although few historical records survive from that time, some accounts found both in Asia and Europe mention a dimming of the sun and extremely cold temperatures. Either a huge volcanic eruption or a large meteorite colliding with Earth could have created a large dust cloud throughout Earth's atmosphere that would have been capable of blocking enough sunlight to lower global temperatures significantly. A large meteorite collision, however, would probably create a sudden bright flash of light, and no extant historical records of the time mention such a flash. Some surviving Asian historical records of the time, however, mention a loud boom that would be consistent with a volcanic eruption. Therefore, the cooling was probably caused by a volcanic eruption.
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The argument is well-present, but not thoroughly well-reasoned. So I would not agree with the speaker’s assertion that the cooling was probably caused by a volcanic eruption but not a meteorite collision.

The threshold problem in the argument is that the relationship between a dimming of the sun and the extremely cold temperatures mentioned by the accounts found both in Asia and Europe is great vague. First of all, the speaker does not provide evidence to prove that such accounts are credible. If not, there would be meaningless to continue such study. Second, even if such account can be believed, still there is no evidence support that the dimming of the sun is relative to the cold temperatures.  Third, even assuming the dimming of the sun have great relationship to do with the cold temperatures, the speaker also cannot assert that such a dimming equates a large dust cloud throughout Earth's atmosphere blocking sunlight. As we know, when a planet is lineal between the sun and the earth, also can blocking enough sunlight happen. Without ruling out these possibilities, it is difficult to believe the speaker's assertion.

Another point worth considering is that the speaker does not consider other possibility that also can cause the large dust cloud, even if the cold temperatures is because of the cloud. In other words, the speaker cannot illustrate that why only a huge volcanic eruption or a large meteorite colliding with Earth could have created a large dust cloud, but not another cause or reason. Lacking of such evidence, also I would not agree with the speaker's assertion.

The third problem involves the speaker’s account of no extant historical records of the time mention such a flash which may be created by a large meteorite collision. So many doubts are in such account To begin with, no extant record in the survive records does not mean that no extant in the all the records of the time. Perhaps, some records with such things are not surviving or have not been found by people. Besides, even no records is extant to such things, also it is possible that people in that time did not write such things which though happened. Moreover, it is extremely possible that the meteorite collision happened without such a flash. In short, if the speaker cannot exclude such possibilities, he should not make sure that a large meteorite collision had happened in that time.

Before I come to my conclusion, it is necessary to point out that a loud boom that mentioned by some records does necessarily indicate that a volcanic eruption happened. Firstly, what is the word “loud” meaning? Perhaps it is just a sound of a stone running from the hill to the foothill, or something else. Many factors can cause such a “loud boom”, and the speaker cannot prove that such a loud boom is relative to the volcanic eruption. Even the loud boom is created by such a volcanic eruption, is the volcanic eruption huge enough? Can it create a large dust cloud? Perhaps the volcanic eruption is just a small one, and a small dust cloud just appeared. Therefore, such evidence cannot support that the volcanic eruption caused a large dust cloud, far the cooling.

In sum, the speaker cannot justify the voting assertion on basis of the scant evidence. To bolster the assertion, the speaker should provide the evidence that there are only two factors- volcanic eruption and meteorite collision. That can cause the large dust cloud, and only the large dust cloud can cause the cooling. To better evaluate the assertion, I would need to know that whether the meteorite collision happened with such a flash or not, and whether such a flash appeared or not. I also would need to know whether the loud boom is relative to the volcanic eruption or not, and whether the volcanic eruption is large enough to cause a large dust cloud.