A45 球拍

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45The following appeared as an editorial ina wildlife journal.

"Arctic deer live on islands in Canada's arctic region. They searchfor 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 whichthey feed, and cold enough, at least some of the year, for the ice to cover thesea 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 causedthe sea ice to melt, we can conclude that the decline in arctic deerpopulations is the result of deer being unable to follow their age-oldmigration patterns across the frozen sea."




In thisargument, the author concludes that the decline in arcticdeer populations is the result of deer being unable to follow their age-oldmigration patterns across the frozen sea. At first glance , this agrumentseems to be convincing ,but further reflection reveals that these evidencesneither constitue a logical statement in support of its conclusion norproviding compelling support making this argument sound and invulnerable.

The thresholdproblem with this argument is that the author assumes that Global warmingtrends directly lead the sea ice over which the deer travel to melt. Althoughthis is entirely possible , the argument lacks evidence to confirm thisassumption. It is most likely that there are some places on earth have atemperature rise while on the other place ,probably on islands in Canada’sarctic region, the temperature doesn’t change or just change a little bit.

The second flawthat weakens the logic of this argument is that the author assumes that thedeer populations are declining according to reports from local hunters.Nevertheless, there is no guarantee that it is necessarily case and it is quitepossible that the time , range and habits of the hunters have changed so thatthey can’t see many arctic deer. In short ,without better evidence ruling outthese and other alternative explanations, it is reasonable to cast considerabledoubt on this assumption.

The last but notthe least important ,even if the author can substantiate all of the foregoingassumptions, his assumption that the decline in arctic deer populations is theresult of deer being unable to follow their age-old migration patterns acrossthe frozen sea is still unwarranted,because no compelling evidence is providedto affirm this assumption. It is much more possible that the arctic deerpopulations are declining because of a large number of hunting or lack of food.Under any scenario, adopting the author’s proposal might harm rather thanbenefit.

To sum up, the conclusion lacks credibility because theevidence cited in the analysis does not lend strong support to what the arguermaintains. Therefore, if the author had considered the given factors discussedabove, the argument would have been more through and logically acceptable.