A - Satellites can be repaired only in orbit.
B - Astronauts are needed to repair them.
C - Without repairs satellites would eventually malfunction.

Conclusion D - Space flights carrying astronauts MUST continue.

What are the assumptions here?

1. Astronauts are the only ones who can repair satellites in orbit.
2. The satellites cannot be left unrepaired, i.e. they MUST be repaired.

WEAKENER


A. This is a dire consequence of not repairing the satellites, and thus actually seems to strengthen the argument that they must be repaired, and that thus astronauts should be there to repair them.

B. Indispensable in the identification.... keyword is INDISPENSABLE. This actually tells us that these satellites MUST be repaired since nothing can replace them. Strengthens the argument.

C. Cut budget for space flights. So maybe fewer space flights now. Does that mean we shouldn't send astronauts in every one of them?

D. More fuel needed to carry repair equipment. Does this mean space flights shouldn't have astronauts all the time? OR that the satellites should not be repaired? What if like B said they are indispensable? It would be worth the extra fuel then wouldn't it? Does not weaken.

E. Robot satellites obsolete. Repairing them is more costly/less practical than sending new, improved satellites into orbit.

BINGO --> This gives us a good reason to say that these satellites need not be repaired. In this argument the only function of astronauts we are concerned with is that they are the only ones who can repair satellites (apparently) So if we don't need to repair them anymore, since it doesn't make financial sense, why MUST we send astronauts in spaceships. Not necessarily right? This weakens the argument that space flights with astronauts MUST continue. They need not.

Pick E.


Irrelevant information, in fact brand new information, is very often a weakener, because it introduces new variables, or questions claims made in the argument. Here the implicit claim was that satellites must be repaired, and E told us they need not be since we can just send new ones.

Tough one, and a bit strangely worded to be honest. Not the best framed question.

I can understand your trouble with B, but hopefully this will help clarify why its not a good choice.

The key assumption to the argument is that weather satellites that are in space must stay there. This closes the logical gap between the premises in the argument and the conclusion. The easiest way to weaken the argument would be to weaken this assumption.

The easiest way to weaken this assumption would be to refute this assumption. In prephrasing my answer I decided I would need to look for an answer that shows why existing space satellites aren't needed. I thought the correct answer would say that better, land based, technologies would be developed, eliminating the need for the satellites, or newer satellites would be a more viable option. Either way the assumption would be denied and the argument weakened.

The reason I crossed out B was that B implies that while forecasters can use computers to identify patterns, satellites are indispensable. In way this actually strengthens the argument. It implies that we need satellites to accurately identify patterns, while computers are a second best.

E actually is a restatement of one of my prephrases, so I went with it.

Hope this helps some.

Thanks,

Jared

Thank you guys!

Now I understand it. So far, I experienced that in weakening you can bring in new information to weaken the conclusion but to weaken the assumption, you need to refute it. I think the key work IS "indispensable".

Thanks guys!