argument47【老兵小组】有拍必回！！！

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TOPIC: 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.
WORDS: 393          TIME: 00:30:00          DATE: 2008-2-20 下午 09:27:55

The author concludes that the cooling was probably caused by a volcanic eruption by citing some surviving records. However, after close scrutiny of the argument, I find there are some logic flaws which may lead to an opposite conclusion of the author's.

First of all, the author regards the correlation between the dimming of the sun and the sudden cooling as the cause-and-effect relationship. However, without any other evidence to substantiate the assumption, we may assume that the sudden fall in temperature is due to other natural forces, such like the cold winds from the sea; especially considering that such cooling description exist just in Asia and Europe accounts which could not represent the whole globle(globe) and the sun dimming would affect the whole, the assumption is more unconvincing.

Even if the dimming of the sun caused the cold temperature, the author assumed that it was just the large dust cloud throught(through) Earth's atmosphere that lead to the dimming while ignoring other causes. Perhaps, at that time, there was a star in the middle location between the sun and Earth and stayed comparatively long, which could also contribute to the dimming and therefore bring about a sudden cooling. What is more, even if the large dust cloud that caused the dimming, the causes of the  large dust cloud may have other alternative explanations in exception of volcanic eruption and meteorite colliding, which lend an incredible support to the final conclusion.

Secondly, even if the cause of the large dust cloud are either volcanic eruption or meteorite colliding, the ruling out of meteorite collision seems unsound.  No extant historical records of the time mention the flash can not indicate that  such flash never occur. We may assume that the records of the flash are lost and therefore could not substantiate the ever collision. Besides, the survival Asian historical records may mistake the sound of collison(collision) to the boom from a volcation(volcanic) eruption. Given the ancients at that time just experienced the volcanic erruption(eruption), but never the meteorite collision and the meteorite collision occasionally happend in a area far from them--like the desert from which the sound changed a lot to sound like the volcanic erruption(eruption) and the flash are too far to observe. Thus, the cooling was caused by the large dust created from the meteorite collision.