argument 45 求各位大侠猛拍

jtdx629UID: 2808303

TOPIC: ARGUMENT45 - The following appeared as an editorial in a wildlife journal.

"Arctic deer live on islands in Canada's arctic region. They search for food by moving over ice from island to island during the course of a year. Their habitat is limited to areas warm enough to sustain the plants on which they feed, and cold enough, at least some of the year, for the ice to cover the sea separating the islands, allowing the deer to travel over it. Unfortunately, according to reports from local hunters, the deer populations are declining. Since these reports coincide with recent global warming trends that have caused the sea ice to melt, we can conclude that the decline in arctic deer populations is the result of deer being unable to follow their age-old migration patterns across the frozen sea."


Supposing the authenticity of the reports from the local hunters, grounding on the fact that arctic deer travel across the frozen sea, then synthesizing the recent global warming trend, the author concludes that the decline in arctic deer population is traced to the deer being unable to migrate as they used to. However, close scrutiny of this evidence reveals that it lends little support for the argument.

Primarily, the major suspicion stems from the doubt whether the number of deer is indeed declining. To be realistic, the description of the local hunters, experienced and objective as it might be, is not sufficient to buttress the deduction of the arguer. Could the conclusion coming from hunters reflect the real population of deer? Without applying rigid statistic method, the report amounts to an aberration. It is entirely possible the route of deer migration cannot be traced by the local hunters, but the population has not been decreasing; conversely, the number of deer may roar sharply due to hunters being unable to capture enough preys. For that matter, the reports cited are unsubstantiated.

Aside from the unreliability of the reports, the global warming trends showing the sea ice is melting would lend support to the opponent's claim if the Canada arctic region typifies the world. It is quite possible that this arctic region do not follow these general trends. Perhaps the region is so well preserved that the climate there is still suitable for the deer living. For that matter, in Canada the trend might be just opposite. Thus, as it stands, the global trends amount to scant evidence that the sea ice in Canada's arctic region is melting.

In addition, even assuming the reports of the local hunters and the trends cited are authentic, the speaker willy-nilly indicates a correlation between the deer population and the melting ice; then concludes that the latter is the cause of the former. While a high correlation is a strong evidence of a causal relationship, in itself it is not sufficient. The editorial fails to rule out other possible explanations, such as the increasing number of predators or declining forage amount, for the cause of the declining population. Any of these scenarios, or other environmental, political regulation for deer hunting, might similarly lead to the result. Lacking clear evidence on causal relationship, the editorial cannot conclude that the melting ice is the primary cause, or even a contributing cause, of the declining population of deer.

What is more, the arguer unfairly presumes the "age-old migration" is the only way the deer take to travel. In relying on the lack of information about the migration method, the speaker ignores the possibility that the deer has been adaptive to the climate changes and has adopted some unknown method to travel, such as swimming between the islands, or not to travel to go through the cold days. Without taking account of this alternative, the arguer cannot draw such a conclusion.

In sum, the editorial supplies a seemingly beneficent evidence, whereas his deduction is not rational. Were there more detail concerning the reliability of the local hunters' report, the conformability of the global warming trend in the region, and clear causal relation between the ice melting and the population declining, the conclusion of the speaker would be relatively strengthened.