Logical Reasoning

PT118 · S3 · Q11 Biologist: Humans have five fingers

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Biologist: Humans have five fingers because we descended from a fish with five phalanges in its fins.

Conclusion

If we humans had descended from six-phalanged fish and thus has six fingers, we'd be just as content with a six-fingered hand as we are with a five-fingered one.

Evidence

We have five-fingers through an accident of evolution (our ancestor had five phalanges).

Our five-fingered configuration is no more or less useful than several other configurations, such as six-fingers per hand.

Evaluate

Since the author is making a comparison between our Actual World and the 6-Fingered World, we should look at what comparison is happening in the Evidence and think about comparison we're measuring in the Conclusion.

The evidence establishes that in the 6-fingered world, our configuration of fingers would be just as useful as our current 5-fingered configuration is.

The conclusion is saying that we would be just as content.

Goal

It looks like this argument is relying on the assumption that, , but maybe there's more to our contentment than just usefulness?

Maybe we would aesthetically prefer the look of the 5-fingered hand to that of the 6-fingered hand, for example.

Since objections to this argument spring from this source, even though 6-fingers would be just as useful, we wouldn't necessarily be just as content, because .... we can strengthen this argument by making "usefulness" seem like the main / only game in town.

Look for an answer saying "all we care about is usefulness" or ruling out the idea that we care about something else.

11.

Which one of the following, if true, most strengthens the biologist's argument?

Everyone is equally content with
No Impact
We don't care whether we're currently equally content or currently content to wavering degrees. The conclusion we're judging is about whether our current contentment (however it's distributed) would be matched in a 6-fingered world.
7% picked this
Humans are never equally content
Inverted Logic
They flipped the illegal lightswitch on this one. We wanted: if it's equally useful ? we're equally content (prem) (conc) And this is giving us if two things are ? we're not equally content not equally useful
3% picked this
Correct
Humans are always equally content
Why this is right
To match the move from Premise to Conclusion, we wanted: if it's equally useful ? we're equally content (prem) (conc) And this is giving us exactly that. If anyone was nervous that it was "too strong", that's the opposite of what we worry about. On Strengthen, Weaken, Paradox, Principle-Justify, and Sufficient Assumption, there's no such thing as too strong. We would only ever worry if something were too weak. Those question stems ask us to pretend this answer is true ... hypothetically, if it were true, which would have the most impact? if valid Which of the following, if true , most .... if assumed
Skill tested: Strengthen · how this choice captures the argument's function is the move to repeat next time.
66% picked this
The perceived usefulness of our
Inference, Not A New Idea
This sounds like an Inference we can pull out of the premises, so it doesn't seem to provide us with anything we didn't already have. We've already accepted that 6-fingered and 5-fingered would be equally useful, because we concede the truth of the premises (99.5% of the time). This answer doesn't address the argument's gaping vulnerability -- what if our contentment is based on more than just usefulness?
24% picked this
At least one species of
Trap
No Impact Deal with Trigger, Not Outcome Whenever you have a conditional conclusion, like If Barack Obama started acting in movies, he would be one of Hollywood's top actors you get no Strengthening or Weakening value out of addressing the trigger. This author isn't suggesting that Obama is even 1% likely to start acting in movies. She's just making a hypothetical conclusion, which you're totally allowed to do. We accept the "if" part of any conditional conclusion, as though it's a Premise already baked in. The only way to argue with this claim is to put yourself in a world where Obama now acts in movies, and try to argue that he wouldn't be one of Hollywood's top actors. Since this answer choice is trying to add some credence to the hypothetical idea of "if we had come from 6-phalanged fish", it has no value whatsoever.
1% picked this

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