Argument150 Sally小组作文贴

colaboyUID: 206650

150The following is a letter to the editor of an environmental magazine.

"The decline in the numbers of amphibians worldwide clearly indicates the global pollution of water and air. Two studies of amphibians in Yosemite National Park in California confirm my conclusion. In 1915 there were seven species of amphibians in the park, and there were abundant numbers of each species. However, in 1992 there were only four species of amphibians observed in the park, and the numbers of each species were drastically reduced. The decline in Yosemite has been blamed on the introduction of trout into the park's waters, which began in 1920 (trout are known to eat amphibian eggs). But the introduction of trout cannot be the real reason for the Yosemite decline because it does not explain the worldwide decline."


In this argument the editor deduce the conclusion based on two reasons, one is the study of the number of amphibians in Yosemite National Park (YNP), the other is the effect of the introduction of the trout into he park's waters. This argument unconvincing because it suffers severs illogical problematic reasoning.

To begin with, the two reasons the editor provided lead little support of the conclusion. He/She just cited the result of the study in YNP, but did not mention what is the case all over the world. The condition in YNP can be very much different with the various ones in the world. He/She did not tell us either the number or the species of the amphibians in all the countries are declining, or there are other factors influence the result of the study. For example, it is entirely possible excess preying the amphibian from other animals even human being can also cause this result, but they are not the reason of the global pollution of water or air.

Additionally, these two reasons only indicate the decline in YNP, but came to no conclusion. The editor did not provide us any evidence that possible water and air pollution exist in YNP, let alone convince us the decline of the amphibians has certain relationship with the global pollution.

Moreover, the editor did not offer any evidence on the decline of the amphibians of the globe or, certain pollution exists of the globe. He/She also did not construct any relationship between the two. Thus, we do not know whether the decline of the amphibians’ number and species are caused by the global pollution, nor it is the result of the introduction of the trout into the park’s waters. Thus we cannot rule out the factor that the decline of the amphibians’ number is caused by the introduction of the trout, not the pollution.

To sum up, the editor fails to substantiate this argument. All the evidences he/she offers are opened to doubt whether they are related to the conclusion or not. Detailed information must be given for further reasoning this argument, rather than based on these factors.