[a习作temp] argument47 kb911小组第6次作业 [复制链接]

WHSYING
UID：2310541

寄托新兵

Rank: 2

声望: 0
寄托币: 289
注册时间: 2007-3-8
精华: 0
帖子: 0

电梯直达

楼主

发表于 2007-8-20 08:54:44 |只看该作者 |倒序浏览

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: 374 TIME: 00:30:00 DATE: 2007-8-20 0:54:45

The author claims that the cooling was probably caused by a volcanic eruption. In order to support the claims, the author cites several evidences such as there is no extant historical records of the time mention a flash. However, the argument relies on a series of unsubstantiated assumption, which makes it unconvincing as it stands.
First of all, the author provides no evidence that the loud boom mentioned in the historical records would be consistent with a volcanic eruption. There are many other possible events can lead the loud boom. Perhaps it was just an enormous typhoon; perhaps it was a collision of the earth and some other comet. Without reliable evidence, the author cannot consider the boom is consistent with a volcanic eruption.
In the second place, even if the boom was just the consistent with a volcanic eruption, there is no proof that this volcanic caused the cooling. Perhaps the cooling was caused by a large meteorite collision, the author consider there is no collision because no extant historical records of the time motions such a flash, it is not necessary the case. The no record of flash never means there is no collision, perhaps the flash was happened but not be recorded, and perhaps the collision happened with no flash. Lacking the assurance evidence that the boom was consistent with a volcanic eruption and the collision never took place, the conclusion is not reliable as it stands.
Finally, the author considers that collision and volcanic eruption are the only reasons for the cooling. However, it is possible that other factors might also contribute to the problem. Perhaps an earthquake can lead the cool; perhaps an enormous typhoon also can cause the temperature decrease. Without ruling out these and other possible factors, the author cannot confidently conclude that the cooling was caused by a volcanic eruption.
In conclusion, the recommendation that the cooling in history was probably caused by a volcanic eruption is not well supported. To strengthen the argument, the author should provide more reliable evidences such as the eruption had happened and the collision never took place. In order to better evaluate the conclusion, I would need more information such as whether there are other ways can lead the temperature decrease.

[ 本帖最后由 WHSYING 于 2007-8-20 09:14 编辑 ]