Q18 - Nutritionist: Because humans have evolved

[ohthatpatrick]

This a Describe the Role question.

We should first read and understand the argument core, and then we'll ask ourselves whether the claim in question is a conclusion, premise, subsidiary conclusion, opposing point, or background fact.

After a first read, it's a little tricky to figure out what the Main Conclusion is.

On one hand, the 1st sentence had a "Because of X, it is clear that Y" structure.

With that wording, we know that X was a premise used to support the conclusion Y.

On the other hand, we have a "THUS" to begin the final sentence.

Language such as "thus/therefore/hence/so/it is clear" always indicates a conclusion, but it doesn't necessarily indicate the main conclusion.

So in this argument we have two conclusions, one prefaced by "it is clear", the other prefaced by "thus".

Remember, some arguments have subsidiary/intermediate conclusions: ideas that have a supporting premise but ultimately are there to support an even bigger claim.

So we need to ask ourselves, "which was the main conclusion and which was the subsidiary/intermediate conclusion?"

We can use the Therefore Test to help us decide.

Which one makes more logical sense?

Humans are still adapted to a diet of wild foods
THEREFORE
The more our diet consists of wild foods, the healthier we will be

or

The more our diet consists of wild foods, the healthier we will be
THEREFORE
Humans are still adapted to a diet of wild foods

The 1st one makes more logical sense. BECAUSE we're adapted to wild foods, we'll be healthier eating more of them.

The question stem is asking us about the "it is clear" claim. We just figured out that that claim was our subsidiary/intermediate conclusion.

We can scan the answers looking for applicable wording.

(D) is correct.

The argument breaks down as

MAIN CONC:
the more our diet consists of wild foods, the healthier we'll be
(why?)
PREM 1:
[because] Straying from this diet often leads to health problems
+
PREM 2 / INTERMEDIATE CONC:
[because] humans are still biologically adapted to a wild food diet
(why?)
PREM:
[because] humans have evolved very little since the development of agriculture

====other answers===

(A) The only support offered for this claim is the very first clause of the argument, "because humans have evolved very little ..."

(B) Justification IS provided for this claim, the very first clause of the argument, "because humans have evolved very little ..."

(C) This answer choice says that the main conclusion would explain the phenomenon of this claim. (i.e. that "the more wild foods we eat the better" would explain the phenomenon that "we are still biologically adapted to wild foods") This is the reverse of how the argument actually works.

(E) This gets the first sentence backwards. The claim that humans evolved very little is a premise in support of the claim in question.

[hyewonkim89]

Hi Patrick,

Thank you for such a great explanation.

I also did the Therefore Test between the two conclusions, and actually thought the second one made sense and picked A right away.

The more our diet consists of wild foods, the healthier we will be
THEREFORE
Humans are still adapted to a diet of wild foods

I thought since humans know eating wild foods is healthy, they will still be adapted to a diet of wild foods.

Or maybe I was just trying to make it sound fine.

Will you please explain why this doesn't make sense?

Thank you in advance!

[ohthatpatrick]

I see what you're saying.

If we had, as evidence, a correlation between people who ate mainly wild foods and better health, we might draw the conclusion that "Oh, well, then I guess that means that humans are still biologically adapted to a diet of wild foods."

However, (A) would still be wrong because the 2nd to last sentence is NOT the only support offered.

If we pick "humans are still adapted to wild foods" as our conclusion then these three ideas would support:
- humans have evolved very little since we stopped eating nothing but wild foods
- straying from this diet often results in illnesses and other problems
- the more our diet consists of wild foods, the healthier we are.

So that's why (A) is wrong no matter what.

But notice how I subtly changed that 3rd bullet point of support.
"the more our diet consists of wild foods, the healthier we are."

Is that what the argument actually said?

No, it said "the healthier we will be". That's really how you can tell that the last sentence can't be treated as evidence for something else. It's not a commentary on what currently is or has been the case. It's not a statement of an observed correlation. It's advice for the future.