argument47[aero小组]第八次作业 by liuyingbnu

liuyingbnuUID: 2321970

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: 477（491）          TIME: 00:30:00          DATE: 2008-1-22 14:59:32

In this argument, the author comes to the conclusion that the cooling of the world in mid-sixth century was probably caused by a volcanic eruption. To support his claim, the arguer points out that a volcanic eruption or a large meteorite colliding with earth may be the possible causes of the cooling. In addition, evidences that no record of bright flash of light at that time is available and that there is a loud boom which indicates a volcanic eruption mentioned in historical records are cited. However tempting as such an argument might be at the first sight, careful examination will reveal that it suffer from reveal logic flaws and the evidence cited are doubtful.

To begin with, the mere fact that no extant historical records of the time mention such a bright flash is insufficient for the author to rule out the possibility that the cooling is due to a large meteorite collision. Maybe people living nearly the location of the incident of collision failed to record it because they were not good at keeping records. Or even, perhaps the collision occurred in the place that was not accessible for people at that time. It is also entirely possible that these records are deserted by people and now disappear without any trace. If either of them is the case, the fact records don not exist can seldom indicate the collision never happened.

Secondly, the author unfairly ascribes a volcanic eruption to the cooling with insufficient information. A loud boom may be consistent with a volcanic eruption. Nevertheless, it is equally possible that it is cause by other phenomena, such as other continental movements. If the volcanic eruption did not occur in deed, how could the author to establish the casual relationship between the volcanic eruption and the cooling. Moreover, the premise that the earth is the only heat resource of earth upon which the argument depend is ungrounded. The author presents no justification for this assumption. With more evidence, the author may discover there are other resources for heating of earth other than the sun. If so, the conclusion about the cause of the cooling is ridiculous.

Close scrutiny will reveal more mistakes in this argument. The author falsely equals the cooling in Asia and Europe to that in the whole world. There is a great possibility that it is the case; however with scarce data on that, this kind of generation may amount to nothing in the end. Further, the author presents a dilemma by presenting either-or choice between the two causes. But he fails to testify that other explanations for this phenomenon are impossible.

To sum up, the argument is logically flaws in several respects. In order to bolter it, the author should resort to sufficient information on the really condition on worldwide temperature at that time. Also, a deeper investigation on the heat resource of earth is required as well as the justified records on possible causes.

这篇写得比较差，惭愧！

[ 本帖最后由 liuyingbnu 于 2008-1-24 20:17 编辑 ]

可乐加冰84UID: 2221571

最近家中有事，30号一定改好！
实在对不起！抱歉抱歉！:L