skbjunior wrote:
One of Hoyle's arguments can be summarized as follows: On earth, all the natural occurrences of methane that we know of are associated with 'methanogens' (methane producing bacteria). In addition, there is evidence that methane is also present in some inter-planetary material in comets. Therefore, it is likely that methanogens are present in these materials as well.
Which of the following is true of this argument?
A. It would be strengthened by the discovery of other compounds which occur both on earth and in comets, and whose terrestrial occurrence is strongly correlated with bacterial action.
B. Since this argument does not appeal to analogies between terrestrial and extra-terrestrial phenomena, it does not need any explanation of how methanogens synthesize methane.
C. This argument has no evidence force with respect to the extra-terrestrial existence of bacteria unless it can be supplemented with an explanation of the process by which terrestrial bacteria synthesize methane.
D. The plausibility of Hoyle's conclusion would be seriously weakened if the existence of methanognic bacteria were revealed to exist on other planets in our solar system through on-site explorations.
E. It would be strengthened if it were discovered that methane is generated in Antarctica without bacterial action at low temperatures, which approximate those of comets far out in the solar system.
Please provide explanation for your answer choice. I will upload OA soon. Thank you!
Here is a discussion of all the options. The questions uses intricate language to confuse the reader but is other wise quite straight forward.
Hoyle's Argument:
On Earth, all natural Methane is made by bacteria.
Natural Methane exists on comets.
Conclusion: Probably comets have bacteria.
A. It would be strengthened by the discovery of other compounds which occur both on earth and in comets, and whose terrestrial occurrence is strongly correlated with bacterial action.
If we find other compounds generated by bacteria on comets then the argument will be strengthened. The argument is strengthened by strengthening the conclusion. The conclusion is that comets have bacteria. If other bacteria produced compounds are found on comets, it WILL strengthen the possibility of bacteria on comets. Hence this options is true.
B. Since this argument does not appeal to analogies between terrestrial and extra-terrestrial phenomena, it does not need any explanation of how methanogens synthesize methane.
This option says that the argument does not compare Earth and comet phenomena so there is no need to explain how bacteria make methane. But this is not true. We do need to know how bacteria make methane because it could help in evaluating the conclusion. Say, if bacteria need presence of oxygen to make methane and oxygen is not present on comets, it could affect our conclusion. So this option is not true.
C. This argument has no evidence force with respect to the extra-terrestrial existence of bacteria unless it can be supplemented with an explanation of the process by which terrestrial bacteria synthesize methane.
This option says that unless the argument gives an explanation of how bacteria make methane, it is a worthless argument. The conclusion has no merit. This is not correct. 'How' is important to know (as discussed in option (B) above) but the argument still has relevance since the presence of methane points toward definite presence of bacteria on Earth so there is a possibility that presence of methane on comets points toward presence of methane on comets too.
D. The plausibility of Hoyle's conclusion would be seriously weakened if the existence of methanognic bacteria were revealed to exist on other planets in our solar system through on-site explorations.
If we found bacteria on other planets, possibility of bacteria on comets strengthens so our argument actually strengthens. This statement says that Hoyle's argument will weaken which is false.
E. It would be strengthened if it were discovered that methane is generated in Antarctica without bacterial action at low temperatures, which approximate those of comets far out in the solar system.
If natural methane was found without bacteria on Earth, it will weaken the possibility of bacteria on comets because then we would have a case where natural methane could exist without bacteria. This statement says that our conclusion will be strengthen which is incorrect.
Answer (A)
close
Updated on: 07 May 2011, 11:03
50%
(02:29)
wrong 
