Oct 2001 Section 1 Q18 Forum

[tracy77]

There seems to be no better answer than B, but I'm a bit confused that if both B and the overall conclusion "The current pattern of human consumption of resources... must eventually change" are true, how can we "do without renewable resource"?

Or should "do without renewable resource" be taken as including other alternatives except for consuming nonrenewable resources?

[cgw]

There seems to be no better answer than B, but I'm a bit confused that if both B and the overall conclusion "The current pattern of human consumption of resources... must eventually change" are true, how can we "do without renewable resource"?

Or should "do without renewable resource" be taken as including other alternatives except for consuming nonrenewable resources?

I thought this was pretty straightforward question. The conclusion says we must give up whatever the nonrenewable resource provided or find a renewable replacement. Choice B eliminates the possibility that we could replace a, hypothetically, scarce nonrenewable resource with a, hypothetically, less scarce nonrenewable resource.

I don't see any indication it says "do without renewable resource" anywhere.

[TylerJonesMPLS]

I think you may have read the “or” in the last sentence the wrong way. You seem to be taking it as, “…we must either do without [renewable resouces] or turn to renewable resources…”

I think the LSAC meant it to read like this, “… we must either do without [iron ore] or turn to renewable resources…”

I had already written an analysis of the question when I realized that you had probably just misread the “or”, but since I wrote it, I’ll keep it in, just in case it helps.

Whenever the LSAT asks for an assumption that is REQUIRED by the argument, it means that they are looking for a background assumption, which must be true, because it would invalidate the whole argument if it were false. Logicians call this a “necessary condition”. Just as in the conditional: If you could drive the car, then the motor was running.
The If clause is the sufficient condition, and the Then clause is the necessary condition. I sure you know all of this. But what many people don’t know is that there is usually an indefinately large number of necessary conditions for every sufficient condition. For instance,
If you could drive the car, then the electric circitry was working.
If you could drive the car, then the brakes were working.
If you could drive the car, then the steering wheel was attached.
If you could drive the car, then the tires had not been stolen.

You can see that you could go on all day listing necessary conditions.

That is why it is usually a waste of time to try to guess ahead of time what the correct answer choice to a required assumption will look like. There are just too many of them.

In the case of 35.1 18, as you say, the conclusion is, we must change our pattern of human consumption.

The argument, which takes metal ore as its example, goes like this:
There is a limited amount of metal ore available. Once that amount of metal ore has been consumed, we will have the option of doing without metal ore, or the option of turning to renewable resources to take the place of metal ore.

Now there is a third option that the argument did not mention. And that is that once we have exhausted the limited amount of nonrenewable metal ore that we have, we can replace the metal ore with a limited amount of nonrenewable super-strenthened plastic, and once that is exhausted we can replace it with another nonrenewable resource, and we can continue doing this forever.

And that is where (B) comes in. (B) says that we cannot replace one nonrenewable resource with another nonrenewable resource and so on forever.

You don’t actually need to make this assumption explicit in the argument because it is obvious that the person who wrote the argument thought that this possibility was so silly that it wasn’t even worthwhile to discuss it. But it is a necessary assumption, and that’s why (B) is the correct AC. (A) is obviousy false. (C) appears to be a contender, but it sounds too much like a tautology to count as a necessary assumption, especially since (B) does explicitedly address a consideration missing from the argument. (D) is just an unsupported prediction, and while (E) is true, it is not a necessary assumption of the argument.

[tracy77]

Hi, just from a grammatical point of view, can I interpret the original sentence as meaning "we must either do without [iron ore] or turn to renewable resources"?

[cgw]

Hi, just from a grammatical point of view, can I interpret the original sentence as meaning "we must either do without [iron ore] or turn to renewable resources"?

Yes, since that is what it is saying. Do without nonrenewables, of which iron ore is one of many.