Argument047 [0710G-summer小组]

laststrikeUID: 2318203

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: 490          TIME: 00:28:25          DATE: 7/23/2007 2:53:04 PM

In the article, the author concludes that the cooling of the Earth in the mid-six century was probably caused by a volcanic eruption. To support his claim, he reasons that no extant historical records mention a sudden bright flash of light would probably created a large meteorite collision. In addition, he cites the historical records of the time mention a loud boom that would be consistent with a volcanic eruption. At the first glance, this argument seems somehow plausible. However, after a clear reflection, it suffered several logic fallacies.

To being with, the author unjustly concludes two possible candidates for the cooling of the Earth. The only facts that the author given is some Asian and European records mention a dimming of sun and extremely cold temperatures. Based on the evidence, myriads of explanations besides the meteorite collision and volcanic eruption would also be valid. Perhaps the people in Asia and Europe migrated to the polemic region that could amounts to the facts. Or perhaps the climates changes so radically that clouds blocked that sun. Or perhaps the geological movement caused some kind of cooling effect like the Ica Age. Without concern these candidates for the cooling of the Earth, the author can not convince me that his two candidates for the only possible explanation.

In addition, even assuming that the two candidates are the only explanation to the cooling of the Earth, the author falsely rules out the meteorite collision based on the mere fact that no extant records mention a bright flash. The scant of the light could be caused by the position it occurred. For that matter, it is possible that the collision occurred in Africa or Arctic regions that the light could not transmit to Asia and Europe. Thus, the records could not reflect the possible fact. Without consider these possible explanations about the scant mention of the bright light, the author fails to convince me his conclusion based on his this questionable speculation.

Finally, the author unfairly conjectures the volcanic eruption is valid based on the mention of a loud boom. The conclusion based on the assumption that the loud boom should occur before the cooling of the temperatures. However, the author provides no evidence to prove this vital assumption, thus, the credibility of the conclusion is highly questionable. The loud boom could entirely possible occurred long after the cooling of the temperatures. Moreover, the author provides no further evidence to support that this laud boom is virtually a volcanic eruption. It could be possible that this laud boom was created by the meteoric collision. Thus, without enough evidence to support the conclusion, the author again fails to convince me the validity of the argument.

In sum, to better strengthen the argument the author should provide more substantial evidence to support his two candidates and further information to rule out one of them. Accordingly, the author fails to convince me the validity of the argument.

[ 本帖最后由 laststrike 于 2007-7-23 15:08 编辑 ]