Logical Reasoning

PT108 · S2 · Q5 Smith's new grazing land consists

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Smith's new grazing land consists entirely of fescue grass.

Conclusion (will most likely = opinion)

Smith's cows will most likely learn to graze exclusively on the grass that does not contain the fungus that makes cows ill when they eat it.

Evidence (since)

Cows will avoid eating a patch of grass if they sense a substance in it that has made them ill.

Smith's new grazing land consists entirely of fescue. Half of the grass contains the fungus.

Evaluate

Are we convinced that Smith's cows will learn to graze on the half of the land that doesn't have the fungus?

If not, why not?

Given that cows will avoid eating a patch of grass if they sense a substance in it that has made them ill, how could we still argue that these cows are not going to learn to graze exclusively on the non-fungus half of the grass?

We could say a few things: - the cows can't sense the substance - the cows can sense it, but won't realize that the fungus is what made them ill - there isn't enough grass for all the cows to only graze on the non-fungus half of the land

Goal

Let's look for an answer Defending against one of those objections: - the cows can sense the substance / can grasp that it was the fungus that made them ill / can all fit into half the land.

5.

Which one of the following is an assumption required by the argument?

  1. At least one other species

    Out of Scope: other fungus

    Why would the author need to believe that there is at least one fungus species in the "other half" of the land? If the other half of the land is fungus free, would that weaken the argument? No, that would strengthen the conclusion that cows will learn to graze exclusively on that half of the land.

    6% picked this

  2. Correct

    At least some cows that

    Why this is right

    The author is thinking that cows will graze on this fungus, get ill from it, and then sense where this fungus is / isn't. That's how she thinks the cows will ultimately graze exclusively on the grass that doesn't have the fungus. The final claim is a conditional premise: If cows sense a substance then they will that has made them ill ? avoid that patch of grass The author's conclusion is claiming that the cows will avoid that patch of grass with the fungus, so she is apparently assuming that this trigger idea is true (that cows will be able to sense the fungus). We call this sort of Assumption an Untriggered Conditional. What does this argument assume: Dan is going to get drunk tonight, because dan always gets drunk if he goes to a party. It's assuming that Dan is going to a party tonight. Again, there was a conditional ("if goes to party ? gets drunk"). The conclusion related to the outcome (Dan will get drunk tonight). And the assumption is just saying, "Yo, you never established that the trigger idea is happening". When we negate this answer, it says, "none of the cows that have been made ill by the fungus are capable of sensing the fungus". Would that weaken? Absolutely! If they can't sense it, then they don't know how to avoid it, which suggests that the author is wrong to think that the cows will ultimately graze exclusively on the non-fungus part of the land.

    Skill tested: Necessary Assumption · how this choice captures the argument's function is the move to repeat next time.

    86% picked this

  3. The fungus that makes cows

    Too Strong

    Too Strong: found in no other Only Thing Mentioned ? Only Thing The author doesn't need to assume that only fescue has this fungus. This is arguable the most common trap answer pattern in Necessary Assumption. They want students to erroneously think, "If the author only mentioned fescue, then I guess this thing only applies to fescue". That's crazy. If we say, "The people who serve in the Army are patriots", are we assuming that "People that serve in other branches of the military aren't patriots"? Of course not.

    4% picked this

  4. The cows are the only

    Too Strong

    Too Strong: only Only Thing Mentioned ? Only Thing This has the same problem as (C). The author doesn't need to assume that only cows get sick from the fungus. If a chicken or a crow also gets sick from the fungus, that doesn't weaken the argument at all. Again, this is playing off the trap thought pattern of, "If the author only mentioned cows getting sick from the fungus, then I guess only cows get sick from the fungus."

    2% picked this

  5. The fungus that is contained

    Too Strong

    Too Strong: cannot without destroying Out of Scope: eradicated This argument has nothing to do with eradicating the fungus or what the collateral damage would be were a farmer to attempt such a thing. If we negate this answer, it says, "It's possible to eradicate the fungus without destroying the grass itself". That does not weaken. Even if the farmer chooses to eradicate the fungus, the conclusion would still potentially make sense (the cows would be grazing exclusively on grass that doesn't contain the fungus).

    3% picked this

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