argument50 [0610G-我们的九月]第31次作业

simplearenUID: 2151889

TOPIC: ARGUMENT50 - From a draft textbook manuscript submitted to a publisher.

"As Earth was being formed out of the collision of space rocks, the heat from those collisions and from the increasing gravitational energy of the planet made the entire planet molten, even the surface. Any water present would have evaporated and gone off into space. As the planet approached its current size, however, its gravitation became strong enough to hold gases and water vapor around it as an atmosphere. Because comets are largely ice made up of frozen water and gases, a comet striking Earth then would have vaporized. The resulting water vapor would have been retained in the atmosphere, eventually falling as rain on the cooled and solidified surface of Earth. Therefore, the water in Earth's oceans must have originated from comets."
WORDS: 479(510)          TIME: 0:30:00          DATE: 2006-8-27

The writer of the draft textbook manuscript is not responsible enough for his or her writing. In this argument, based on some unsubstantiated assumptions and a series of groundless reasoning, the arguer hastily concludes the water in Earth's oceans must have originated from comets. A careful scrutiny reveals the argument unconvincing as it stands.

To begin with, the arguer unfairly assumes that lots of comets have struck earth. No evidence is provided that there are lots of comets that have struck earth. In this way, if indeed no comets have come to earth before the oceans' formation, the arguer's assumptions are entirely wrong. Or the comets are really very few, it is impossible for the water from them to compose the large oceans on the earth. Without evidence about strikes from comets, the arguer could not strongly support the argument.

What is more, even assuming lots of comets have struck earth, it still lends insufficient evidence to the assumption that water from these comets was retained by earth. As to the background the arguer provides in the argument, in the initial period of the formation of the earth, gravitation is not powerful enough to keep the water in earth. If this is true, then the comets striking earth in this era must not contribute to the water in Earth's oceans, since the water vaporized from frozen water and gases made comets can not be attracted by the gravitation of earth. Or on the other hand, if the comets in this period was responsible to the water composition on earth, the arguer is likely to commit a self-contradiction, because he or she claims that before the size of earth was big enough any water in the earth have evaporated and gone off into space. If this is the case, the water in Earth's oceans would still not be ascribed to comets.

Finally, granted that some water from comets left on earth, it is still too hasty to conclude all water in Earth's oceans must have originated from comets. The arguer fails to take into account other factors might contribute to the water in Earth's oceans. It is entirely possible the chemical changes took place in the inner earth generated water, and finally formed oceans. Besides, other substance for outer space might also bring water to earth, since comets are not the sole object from outside earth. For instance, meteorites should also be considered for their contribution to the water in Earth's oceans. Thus, the water in oceans can be ascribed to many reasons rather than the mere variable the arguer concludes.

To sum up, lack of sufficient evidence and some flaws in the reasoning throughout the argument largely undermine the conclusion the water in Earth’s oceans must have originated from comets. To strengthen it the arguer must provide clear evidence that lots of comets have struck earth and the water they brought with was retained by gravitation of the earth. To better evaluate the argument, the arguer must take into account alternative explanations of the source of water in Earth's oceans.

lanyelovemeUID: 2234077

The writer of the draft textbook manuscript is not responsible enough for his or her writing. In this argument, based on some unsubstantiated assumptions and a series of groundless reasoning, the arguer hastily concludes the water in Earth's oceans must have originated from comets. A careful scrutiny reveals the argument unconvincing as it stands.

To begin with, the arguer unfairly assumes that lots of comets have struck earth. No evidence is provided that there are(were) lots of comets that have struck earth. In this way, if indeed no comets have come to earth before the oceans' formation, the arguer's assumptions are entirely wrong. Or the comets are really very few, it is impossible for the water from them to compose the large oceans on the earth. Without evidence about strikes from comets, the arguer could not strongly support the argument.

What is more, even assuming lots of comets have struck earth, it still lends insufficient evidence to the assumption that water from these comets was retained by earth. As to the background the arguer provides in the argument, in the initial period of the formation of the earth, gravitation is not powerful enough to keep the water in earth. If this is true, then the comets striking earth in this era must not contribute to the water in Earth's oceans, since the water vaporized from frozen water and gases made comets can not be attracted by the gravitation of earth. Or on the other hand, if the comets in this period was responsible to the water composition on earth, the arguer is likely to commit a self-contradiction, because he or she claims that before the size of earth was big enough any water in the earth have evaporated and gone off into space. If this is the case, the water in Earth's oceans would still not be ascribed to comets.(地球上的海洋可能是在地球形成以后再形成的啊)
Finally, granted that some water from comets left on earth, it is still too hasty to conclude all water in Earth's oceans must have originated from comets. The arguer fails to take into account other factors might contribute to the water in Earth's oceans. It is entirely possible the chemical changes took place in the inner earth generated water, and finally formed oceans. Besides, other substance for outer space might also bring water to earth, since comets are not the sole object from outside earth. For instance, meteorites should also be considered for their contribution to the water in Earth's oceans. Thus, the water in oceans can be ascribed to many reasons rather than the mere variable the arguer concludes.

To sum up, lack of sufficient evidence and some flaws in the reasoning throughout the argument largely undermine the conclusion that the water in Earth’s oceans must have originated from comets. To strengthen it the arguer must provide clear evidence that lots of comets have struck earth and the water they brought with was retained by gravitation of the earth. To better evaluate the argument, the arguer must take into account alternative explanations of the source of water in Earth's oceans.

第三段所指的是原文的逻辑错误吗？

simplearenUID: 2151889

YES
没说先形成海洋再形成地球啊