argument47 [0710G ＋U Aug小组]第23次作业

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题目：ARGUMENT47 - 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.
字数：283          用时：00:25:00          日期：2007-8-17 16:05:43

The arguer claims that a volcanic eruption rather than a meteorite collision resulted in a great cooling in history since a big sound maybe accompanied with a volcanic eruption mentioned in Asian records while no material recorded the great light followed a collision. This argument suffers several flaws as following.

Firstly, the arguer makes a hasty mistake to exclude the impossibility of any meteorite collision totally. This exclusion is based on the assumption that a large meteorite collision would probably create a sudden bright flash and the fact that no extant historical records have mentioned such a flash. However, if a large meteorite collision might happened in an unexplored places where no one lived, it is natural people cannot see it and write it down. At the same time, it is very possible that our ancestors have recorded a collision but these records have not been found or been destroyed by the time. Another possibility is many little meteorite collisions happened which would not necessarily create a flash. Without wiping these doubts out, the arguer cannot exclude the collision out of reasons.

   In the second place, the arguer cited some surviving Asian historical records as evidence to prove that a volcanic eruption resulted in the cooling. However, these records only mention a loud boom which was not necessarily caused by a volcanic eruption. Other possible reasons include collisions of other meteorites outside which caused a loud boom people in the Earth can also hear. Without providing other evidence, we cannot ensure it was a volcanic eruption just because of a loud boom.

  Granted such a volcanic eruption happened in the history, the arguer also has some mistakes on his conclusion of attributing the cooling to the eruption.
Firstly, the arguer doesn't provide evidence to prove that the cooling was after the eruption. If the temperature had begun to decrease before the eruption, the two things would have nothing to do with each other.  Secondly, this eruption is only mentioned in the Asian records and cannot be seen in records of other places so that it is highly possible that this eruption happened in Asia. Is the eruption in Asia capable to create an enough large dust cloud to cover the Earth's atmosphere from Asia to Europe? Before the further evidence is provided, the arguer cannot give a certain and satisfactory answer to this question. Before taking these considerations into accounts, the arguer cannot convince us his conclusion.

To make the argument more logically acceptable, the arguer should develop further investigation on Asian records about a great boom, and provide more exact information about the time and the effects of the volcanic eruption. To be more serious, more researches about the possible collisions are also needed.

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